TEKNISK RIKTLINJE Enhet, verksamhetsområde Datum Version NT, Teknik 09-02-06 C TR 1-10E Samråd NF, NI Vattenfall Eldistribution Svenska Kraftnät 09-02-06 TR 1-10E rev C Tekniska Riktlinjer POWER TRANSFORMERS 2 MVA AND ABOVE Introduction These guidelines are mainly based on Standard SS-EN 60076. The guidelines specify alternative in the case of more possibilities and also include additions and elucidations to the standard. The guidelines can be made binding by the Purchaser and will then specify the requirements which together with the applicable standard are valid for the design and testing. This document replace TR 010:1. It has been compiled on order of Svenska Kraftnät (Swedish National Grid) and Vattenfall Eldistribution AB. It has been approved as a suitable support for purchase.
Transcript
TEKNISK RIKTLINJE
Enhet, verksamhetsområde Datum Version
NT, Teknik 09-02-06 C TR 1-10E Samråd
NF, NI
Vattenfall Eldistribution
Svenska Kraftnät 09-02-06 TR 1-10E rev CTekniska Riktlinjer
POWER TRANSFORMERS 2 MVA AND ABOVE
Introduction These guidelines are mainly based on Standard SS-EN 60076. The guidelines specify alternative in the case of more possibilities and also include additions and elucidations to the standard. The guidelines can be made binding by the Purchaser and will then specify the requirements which together with the applicable standard are valid for the design and testing. This document replace TR 010:1. It has been compiled on order of Svenska Kraftnät (Swedish National Grid) and Vattenfall Eldistribution AB. It has been approved as a suitable support for purchase.
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Index
1 SCOPE 9
2 STANDARDS 9
3 OPERATING CONDITIONS 11 3.1 Mode of operation .................................................................................................11 3.2 Ambient temperature.............................................................................................11 3.3 Network data ..........................................................................................................12
4 ELECTRICAL DATA AND OTHER MAIN CHARACTERISTICS 13 4.1 Ratings......................................................................................................................13 4.2 Connection symbol ................................................................................................14 4.3 Tapping range .........................................................................................................14 4.4 Insulation levels, creepage distances and air clearances....................................14
4.4.1 Insulation levels ..........................................................................................14 4.4.2 Air clearances ..............................................................................................14 4.4.3 Creepage distances......................................................................................15 4.4.4 Safety distances for inspection platform .................................................16
4.5 Short circuit impedances (Impedance voltage) ..................................................16 4.6 Short circuit withstand capability .........................................................................16 4.7 Loading capability ..................................................................................................17
4.7.1 General .........................................................................................................17 4.7.2 Loading cases for inter-bus transformers ...............................................17 4.7.3 Loading cases for generator step up transformers ................................18 4.7.4 Additional loading requirements ..............................................................20
4.8 Neutral point loading.............................................................................................21 4.8.1 Inter bus transformers ...............................................................................21 4.8.2 Transformers for HVDC ..........................................................................21 4.8.3 Non effectively earthed transformers......................................................21
4.9 Type of cooling.......................................................................................................21 4.10 Sound levels ..........................................................................................................21 4.11 Core design............................................................................................................22 4.12 Winding design .....................................................................................................22 4.13 Insulation system..................................................................................................23 4.14 Other internal design requirements ...................................................................23 4.15 Alternative designs ...............................................................................................23
4.15.1 Stabilising winding....................................................................................23 4.15.2 Auxiliary winding......................................................................................23 4.15.3 Off-circuit tap changing and change over between system voltages 24
4.16 Other data .............................................................................................................24 4.16.1 Supply voltages for motors, control equipment etc: ...........................24 4.16.2 Contact breaking capacity .......................................................................25 4.16.3 Enclosure class and degree of protection .............................................25 4.16.4 Control equipment insulation levels etc................................................25 4.16.5 Disturbance requirements .......................................................................25
9 SUPERVISORY EQUIPMENT 32 9.1 Gas and oil actuated relay .....................................................................................32 9.2 Oil level indicator ...................................................................................................33 9.3 Temperature gauges (thermometers)...................................................................33 9.4 On-load tap-changer overpressure relay .............................................................34 9.5 Cooling equipment gauges and transmitters ......................................................34 9.6 On-line dissolved gas monitor .............................................................................35
10 COOLING EQUIPMENT 35 10.1 General ..................................................................................................................35 10.2 Cooler control equipment...................................................................................36
11 CONTROL EQUIPMENT DESIGN 39 11.1 General design ......................................................................................................39 11.2 Ventilation, heating and lighting ........................................................................39 11.3 Terminal blocks ....................................................................................................40
11.3.1 General.......................................................................................................40 11.3.2 Disposition of terminal groups in the control cabinet........................40 11.3.3 Disposition of terminal groups in the OLTC motor drive ................41 11.3.4 Disposition of terminal groups in the current transformer cubicle ..42
12 BUSHING CURRENT TRANSFORMERS 43 12.1 General ..................................................................................................................43 12.2 Electrical data........................................................................................................43
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12.2.4 Rated short time currents ........................................................................44 12.2.5 Insulation levels ........................................................................................44 12.2.6 Cores and windings ..................................................................................44
15.10.1 General.....................................................................................................52 15.10.2 Longitudinal movement ........................................................................52 15.10.3 Lateral movement...................................................................................52
16 CORROSION PROTECTION AND SURFACE TREATMENT 54 16.1 Transformer tank, OLTC tank...........................................................................54 16.2 Connection boxes, cubicles and OLTC motor drive......................................54
16.2.1 Alt 1: Painting ...........................................................................................54 16.2.2 Alt 2:Hot dip galvanising.........................................................................54
19.1.1 Rating plate................................................................................................59 19.1.2 Diagram plate ............................................................................................59 19.1.3 Accessory plate (for Um ≥ 170 kV).......................................................59 19.1.4 Oil circuit diagram (for Um ≥ 170 kV) .................................................59 19.1.5 On-load tap-changer and motor drive plate.........................................59 19.1.6 Bushing current transformer plate and marking..................................60 19.1.7 System voltage re-connection plate .......................................................60 19.1.8 Other plates ...............................................................................................60
20 INFORMATION IN THE BID 61 20.1 General ..................................................................................................................61 20.2 Bid content............................................................................................................61
23 FACTORY ACCEPTANCE TESTS. FINAL INSPECTION. 63 23.1 General ..................................................................................................................63 23.2 Standards. Testing specifications. ......................................................................64 23.3 Testing environment............................................................................................64 23.4 Instrumentation....................................................................................................64 23.5 Tolerances .............................................................................................................64 23.6 Test results and test reports................................................................................64
23.6.1 General.......................................................................................................64 23.6.2 Bushing current transformers.................................................................65
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23.7 Routine tests..........................................................................................................65 23.7.1 Measurement of winding resistance (SS-EN 60076-1, Cl 10.2)......... 6523.7.2 Measurement of impedance voltage, short circuit impedance and
load loss (SS-EN 60076-1, Cl 10.4) ........................................................65 23.7.3 Measurement of no-load loss and current (SS-EN 60076-1, Cl
10.5) .............................................................................................................66 23.7.4 Measurement of zero sequence impedance (SS-EN 60076-1, Cl
23.8 Type tests...............................................................................................................68 23.8.1 Zero sequence impedance measurement ..............................................68 23.8.2 Lightning impulse test (SS-EN60076-3, Cl 13)....................................68 23.8.3 Temperature rise test ...............................................................................69 23.8.4 Overload temperature rise test ...............................................................69 23.8.5 Sound level measurement (SS-EN 60076-1, Cl 8.1.3 d) .....................70 23.8.6 Thermal and dynamic short circuit withstand test. .............................70 23.8.7 On load tap changer.................................................................................70 23.8.8 Bushings creepage distance verification for polluted conditions ...... 7023.8.9 Bushing current transformers.................................................................71 23.8.10 Inspection and testing of accessories ..................................................71
24 SITE TESTS 71 24.1 Tests on transformer ready for operation ........................................................71
24.1.1 Transformers 100 MVA and above and all GSU and HVDC units .7124.1.2 All other transformers .............................................................................72
24.2 Tests in service......................................................................................................72 24.2.1 Transformers 100 MVA and above and all GSU and HVDC units .7224.2.2 All other transformers .............................................................................72
24.3 Site test certificates...............................................................................................72
25 TIME SCHEDULES 72
26 DOCUMENTATION 72 26.1 General ..................................................................................................................72 26.2 Tender documents ...............................................................................................73 26.3 Documents for approval .....................................................................................73 26.4 Instruction manual ...............................................................................................73
27 Appendix 1 75 27.1 THE DRY SALT LAYER (DSL) POLLUTION TEST METHOD .........75
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27.1.3 General description of the DSL test method.......................................76 27.1.4 Test procedure ..........................................................................................78 27.1.5 Test Conditions ........................................................................................79 27.1.6 Acceptance criterion ................................................................................80 27.1.7 References..................................................................................................80
28 Appendix 2 81 28.1 DATA COMPILATION FOR POWER TRANSFORMERS....................81
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1 SCOPE These guidelines cover three phase 50 Hz oil immersed power transformers rated 2 MVA and above. Four categories are dealt with: A Distribution system power transformers - rated 2 - 100 MVA and highest voltage for equipment 12 - 170 kV with recommended ratings B Inter-bus transformers - interconnecting voltage systems 82,5 kV and above C Generator step up (GSU) transformers D High Voltage DC (HVDC) transformers 2 STANDARDS If standards referred to have been revised, the ones in force at the ordering date shall be considered as valid. SS-EN documents are the ruling requirements, thereafter CENELEC (EN, HD or TS documents) and thereafter IEC or ISO. SS-EN / EN / IEC 60076 Power transformers SS-EN 60076-1 Part 1: General SS-EN 60076-1/A1 Part 1: Amendment No. A1 SS-EN 60076-1/A12 Part 1: Amendment No. A12 SS-EN 60076-2 Part 2: Temperature rise SS-EN 60076-3 Part 3: Insulation levels and dielectric tests IEC 60076-4 Part 4: Guide to the lightning impulse and switching impulse testing –Power transformers and reactors IEC 60076-5 Part 5: Ability to withstand short circuit IEC 60076-7 Part 7: Loading guide for oil-immersed power transformers IEC 60076-8 Part 8: Application Guide SS-EN 60076-10 Part 10: Determination of sound levels IEC 60076-10-1 Part 10-1: Determination of sound levels .- Application guide SS-EN 60076-11 Part 11: Dry-type transformers IEC 60076-14 Part 14: Design and application of liquid-immersed power transformers using high-temperature insulation materials IEC 61378-2 Converter transformers – Part 2: Transformers for HVDC applications SS-EN 50216 Power transformer and reactor fittings SS-EN 50216-1 Part 1: General SS-EN 50216-2 Part 2: Gas and oil actuated relay for liquid immersed transformers and reactors with conservator SS-EN 50216-2/A1 Part 2: Amendment No. A1
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SS-EN 50216-3 Part3: Protective relay for hermetically sealed-liquid immersed transformers and reactors without gaseous cushion SS-EN 50216-3/A1 Part 3: Amendment No. A1 SS-EN 50216-4 Part 4: Basic accessories SS-EN 50216-5 Part 5: Liquid level, pressure devices and flow meters SS-EN 50216-5/A1 Part 5: Amendment No. A1 SS-EN 50216-5/A2 Part 5: Amendment No. A2 SS-EN 50216-6 Part 6: Cooling equipment – Removable radiators for oil- immersed transformers SS-EN 50216-7 Part 7: Electric pumps for transformer oil SS-EN 50216-8 Butterfly valves for insulating liquids SS-EN 50216-9 Oil-to-water heat exchangers (not published) SS-EN 50216-10 Oil-to air heat exchangers (not published) SS-EN 10088-3 Stainless steel – Part 3: Technical delivery conditions for semi finished products, bars, rods, wire, sections and bright products of corrosion resisting steels for general purpose SS-EN 50180 Bushings above 1 kV up to 36 kV and from 250 A to 3,15 kA for liquid filled transformers SS-EN 50243 Outdoor bushings for 24 kV and 36 kV and for 5 kA and 8 kA for liquid filled transformers SS-EN 50299 Oil-immersed cable connection assemblies for transformers and reactors having highest voltage for equipment Um from 72,5 to 550 kV SS-EN 50386 Bushings up to 1 kV and from 250 A to 5 kA, for liquid filled transformers CLC TS 50458 Capacitance graded outdoor bushings 52 kV up to 420 kV for oil immersed transformers (not published) IEC 60038 IEC standard voltages SS-EN 6044-1 Instrument transformers; Part 1: Current transformers SS-EN 60071 Insulation co-ordination; Part 1, 2 and 5 SS-EN 60137 Insulating bushings for alternating voltages above 1000 V SS-EN 60214-1 On-load tap-changers IEC 60214-2 Application guide for on-load tap-changers SS-EN 60296 Fluids for electrotechnical applications - Unused mineral insulating oils for transformers and switchgear IEC 60416 General principles for the formulation of graphical symbols SS-EN 60417 Graphical symbols for use on equipment SS-EN 60507 Artificial pollution tests on high-voltage insulators to be used on a.c. systems SS-EN 60529 Degrees of protection by enclosures (IP code) IEC TR 60616 Terminal and tapping markings for power transformers SS-EN 60617 Graphical symbols for diagrams SS-EN 60664-1 Insulation co-ordination for equipment within low- voltage systems IEC TR 60815 Guide for the selection of insulators in respect of polluted conditions
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IEC 60905 Loading guide for dry-type power transformers SS-EN 61000 Electromagneitic compatibility; Part 1 - 6 (IEC or EN shall apply if no SS-EN standards are published) SS-EN 61140 Protection against electric shock – Common aspects for installation and equipment IEC TR 61462 Composite insulators – Hollow insulators for use in outdoor and indoor electrical equipment – Definitions, test methods, acceptance criteria and design recommendations IEC 62199 Bushings for d.c. application IEC 62155 Hollow pressurized and unpressurized ceramic and glass insulators for use in electrical equipment with rated voltages greater than 1000 V SS-EN ISO 1461 Hot dip galvanized coatings on fabricated iron and steel articles – Specifications and test methods SS-EN ISO 9001 Quality systems – Requirements SS-EN ISO 10684 Fasteners – Hot dip galvanized coatings SS-EN ISO 12944 Paints and varnishes – Corrosion protection of steel structures by protective paint systems; Part 1 - 8 SS-EN ISO 14001 Environmental systems – Requirements with guidance for use SS-ISO 67087 Pipe work components – Definition and selection of DN (nominal size) SS 14 2324 Stainless steel – SS steel 23 24 SS 421 01 01 Power installations exceeding 1 kV AC Cigré Report 204 Guidelines for conducting design reviews for transformers 100 MVA and 123 kV and above Cigré Report 209 The short circuit performance of power transformers ELSÄK-FS 2004:1 Elsäkerhetsverkets föreskrifter (New Swedish Safety Code) AFS 1993:10 Swedish Work Environment Authority Regulations 3 OPERATING CONDITIONS 3.1 Mode of operation The transformers shall if not otherwise specified be designed for outdoor erection and continuous operation. 3.2 Ambient temperature As a lower limit of ambient air temperature –40°C shall apply. (Deviation from SS-EN 60076-1, Cl 1.2.1) For all equipment due consideration shall be taken to the increased maximum ambient temperature caused by the temperature of the transformer tank which is assumed to reach 105°C on the cover. The lower limit ambient temperature – 40°C shall be accounted for as well.
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For built in bushing current transformers the following shall apply (if not otherwise verified by the supplier): - maximum ambient temperature 115°C - maximum daily average temperature 105°C The supplier shall demand detailed information of how the transformer would be installed at site. If the purchaser in the Compilation of technical data requires a site installation other then “in open air”, the supplier shall, dependent on the kind of site installation, give information about minimum distances around the transformer. A drawing with a proposal of the transformer arrangement shall be enclosed with the tender. The transformer shall be constructed in such a way that the allowed temperature rises shall not exceed the stated requirements in IEC 60076 on site. Protective walls shall allow the cooling equipment to be located inside. Protective walls for the purpose of sabotage protection shall, if built by Svenska Kraftnät, alternatively financed by Svenska Kraftnät funds aimed for emergency management, fulfil the requirements stated in TR09-15. 3.3 Network data If not otherwise stated the system earthing conditions are given in Table 3.1 and the maximum network short circuit power levels are given in Table 3.2. (Note that all conceivable combinations of lower levels may be at hand). The given values apply also for multi winding transformers.
Table 3.2: Network short circuit power The type of system earthing for the different networks is listed in Table 3.1, System earthing. If not otherwise stated the given range of the ratio between the zero sequence impedance and the positive sequence impedance shall be valid. 4 ELECTRICAL DATA AND OTHER MAIN CHARACTERISTICS 4.1 Ratings For transformers category A the ratings shall be chosen from Table 4.1.
Rated power (MVA) 4 6,3 10 16 25 40 63 100 Rated voltage (kV) Approximate impedance voltage
Table 4.1: Recommended standard ratings Rated voltage 140 kV is used in the southern half of Sweden and 150 kV in the northern half. In some cases 145 kV is chosen for full flexibility. For other transformers the ratings will be specified in every single case. In some cases the ratings will be specified indirectly by means of a so called normal loading case (“Normal case” in Clause 4.7) from which the ratings and impedance voltage will be calculated. In some cases a "high-load" case will be specified for inter-bus transformers together with maximum allowable winding hotspot temperature for given ambient conditions. From these conditions a "conventional" rated power shall be established.
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4.2 Connection symbol Transformers of category A shall normally have the connection symbol YNyn0. For other transformers the connection symbol is specified in every single case. 4.3 Tapping range The tapping range for transformers of category A shall be selected from Table 4.1. The tapping range for other transformers is specified in every single case. 4.4 Insulation levels, creepage distances and air clearances. 4.4.1 Insulation levels Insulation levels shall fulfil the requirements in Table 4.2.
Table 4.2: Highest voltage for equipment and insulation levels Note 1 For phase to phase insulation the following addition shall apply 145 kV LI550 AC 275 170 kV LI550 AC 275 245 kV SI750 LI850 420 kV SI1050 LI1300 Note 2 For the neutral point of autotransformers the following shall apply: 420/145 kV LI250 AC95 420/170 kV LI250 AC95 420/245 kV LI250 AC95 In some cases LI550 AC230 may be specified 4.4.2 Air clearances The requirements on minimum air clearances are summarised in Table 4.3.
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Table 4.3: Minimum air clearances Notes to Table 4:3:
• Air clearances for 170 kV and below are based upon SS 421 01 01 • Air clearances for 245 and 420 kV are based upon SS EN 60076-3 • The air clearance is assumed to be measured from bushing live parts • In some cases the clearances have to be increased to account for the size of
connectors 4.4.3 Creepage distances The creepage distance requirements for ceramic and polymeric insulators in clean and polluted environment are summarised in Table 4.4.
Minimum creepage distance Ceramic type Polymeric type Highest voltage
• Pollution classes according to IEC 60815 • For an alternative method of ceramic type insulator performance in polluted
environment refer to Clause 23.8.8.
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• For polymeric insulators the creepage distance is not a relevant parameter for the performance in polluted environment. For the performance verification refer to Clause 23.8.8
• For transformers having highest voltage for equipment 245 and 420 kV environment Class II shall apply for all windings.
• The ratio (creepage distance) / (insulator length) must not exceed 3.5 for ceramic type insulators.
• In case of environment Class II or III the insulator shall be designed with alternating short and long sheds, i.e. of the self cleaning type.
• Creepage distances are given as minimum length. 4.4.4 Safety distances for inspection platform For the design of the inspection platform and its ladder minimum safety distances equal to the earth air clearance above increased by 6 % shall apply. When applying this the distance from the neck to the finger tip is assumed to be 900 mm and the distance from the neck to the sole of the foot to be 1600 mm. 4.5 Short circuit impedances (Impedance voltage) For standardised (A) transformers the impedances are chosen from Table 4.1 if not otherwise stated (NOTE: Typical values). For other transformers the impedances are specified in every single case. Limitations on zero sequence impedances could be set depending on size of neutral reactor or for the performance of the network system. 4.6 Short circuit withstand capability The transformers shall withstand external short circuits on any voltage level. For a transformer set comprising a main unit and a regulating unit the short circuit withstand requirement also applies to faults at the connections between the two units. The following shall be accounted for:
• currents at three phase and two phase short circuits and earth faults • the transformer operating at 105% of rated voltage • the from the network incoming short circuit power to each bus is assumed to
vary linearly with the voltage • the system earthing and the most unfavourable ratio between the zero
sequence and positive sequence network impedances • the short circuit impedances being 0.95 times the guaranteed values • for windings with non effectively earthed neutral point it shall be assumed
that no earth fault can occur between the line and neutral on the transformer itself
• generator step-up transformers shall also be capable of withstanding switching in at 180° phase opposition
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A new transformer shall be able to withstand minimum three consecutive three phase short circuits at the dimensioning short circuit condition. The dimensioning short circuit current halved a new transformer must be able to withstand nine consecutive short circuits. 4.7 Loading capability 4.7.1 General If not otherwise stated all transformers, even multi winding transformers, shall be capable of continuous operation with rated current in all windings without exceeding the allowable standardised temperature rises. In addition the transformers shall, if specified, fulfil the loading requirements in Clause 4.7.2 Loading cases for inter-bus transformers and Clause 4.7.3 Loading cases for generator step up transformers. Further requirements are specified in Clause 4.7.4. 4.7.2 Loading cases for inter-bus transformers
Loading cases for verification and/ or optimising of rated voltages Case No. OLTC
Pos - Winding
I Winding II
Winding III
Winding IV
Unit
#0 No-load ±0 U ? U2r U3r kV
U U1 U2 ? kV P ? P2 P3 MW
#1 Normal case
±0 Q ? Q2 Q3 Mvar
U U1 U2 ? kV P ? P2 P3 MW
#2 Control case
? Q Q1 ? Q3 Mvar
U kV P MW
#3 Control case
Q Mvar
U KV P MW
#4 Control case
Q Mvar
U ? U2 ? kV P ? P2 P3 MW
#5 Control case
X Q ? Q2 Q3 Mvar
U U1 ? ? KV P ? P2 P3 MW
#6 Peak load, emergencyoperation Hot-spot temp °CAmbient temp °C
Y Q ? Q2 Q3 Mvar
U ? U2 ? kV #7 Temperature rise test
Z P ? P2 P3 MW
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(conventional)
Q ? Q2 Q3 Mvar
Sign conventions: -Positive power = power into the winding -Negative power = power out of the winding -A reactor is consuming reactive power -A capacitor is producing reactive power
Table 4.5: Loading cases for inter-bus transformers
1,2
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0,00 6 12 1
0,2
0,4
0,6
load
(p.u
.) 0,8
1,0
8 24
time of day
Figure 4.1: Emergency operation for inter-bus transformers
Notes to Table 4.5 and Figure 4.1:
• The "Normal case" is decisive for the determination of the no load ratio and
Peak lo rge e r at emergency op ion acco ing to F re 4.1 E rgency eration.
es marke with " ll be ca d by idde ufa er. The transformer losses shall be considered.
ombined ain d regul (boo rans th ding lid with the two operating together.
imum allowed te per ure rises ccording o SS-EN 2 shall be fulfilled in all the loa g e for "Pe load / E cy
n" where the m ature re men spec Cl .7.4. 4.7.3 Loading cases for generator step up transformers
for verificatio d optimisi ed s
the impedance voltage. • The " ad / Eme ncy operation" is th base for the load p ofile
erat rd igu me op• Valu d " ? sha lculate the b r /man ctur• • In case of c
cases are va m an ating ster) t formers e loa
• Max m at a t 60076din cases exc pt ak mergen
operatio te per quire ts are ified in ause 4
Loading cases n an /or ng of rat voltageCase No. OLTC
Pos - Winding Winding Winding Winding Unit
I II III IV #0 No-load 2r 3r - U ? Ug Ug kV
U 100%UN Ug2r Ug3r kV #1 Normal case
- P ? Pg2r Pg3r MW
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U1=normal UN Pg=Pgr Q1=0
Q 0 ? ? Mvar
U 95%UN ? ? kV P ? Pg2r 3r Pg MW
#2 Control case U1=95%UN Pg=Pgr, Q1=-1/3×Pgr
- Q Q1 ? ? Mvar
U 100%UN ? ? kV P ? Pg2r Pg3r MW
#3 Control case U1=100%UN
Q1=-Pg=Pgr,1/3×Pgr
- Q Q1 ? ? Mvar
U 105%UN ? ? kV P ? Pg2r Pg3r MW
#4 Control case U1=105%UN Pg=Pgr, Q1=-1/4×Pgr
- Q Q1 ? ? Mvar
U ? ? ? kV P ? 0 0 MW
#5 Control case U1=100%UN Pr=0, Q1=1/6×Pgr
- Q Q1 ? Mvar ?
U ? Ug2r Ug3r kV P ? Pg2r Pg3r MW
#6 Control case Hotspot 98°C, ambient
Qg=1/3×P
3r Mvar 20°C - Ug=100%Ugr Pg=Pgr
Q ? 1/3×Pg2r 1/3×Pg
gr U ? Ug2r-5% Ug3r-5% kV
Vattenfall Eldistribution
P ? Pg2r Pg3r MW #7 Temperature rise test (conventional) - Ug=95%Ugr Q ? 1/3×Pg2r 1/3×Pg3r Mvar Pg=Pgr Qg=1/3×Pgr Sign conventions: Legend: - Positive power = power into the winding - N = network - Negative power = power out of the winding
- r = rated
- A reactor is consuming reactive power - g = generator - A capacitor is producing reactive power - 1,2,3 =winding #
Table 4.6: Loading cases for generator step up transformers Notes to Table 4.6: - The "Normal case" is decisive for the determination of the no load ratio and the
impedance voltage. - Values marked with " ? " shall be calculated by the bidder/manufacturer. - The transformer losses shall be considered. - Maximum allowed temperature rises according to SS-EN 60076-2 shall be
fulfilled in all the loading cases except for Case #6 where other requirements are specified.
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4.7.4 Additional loading requirements The transformers shall also fulfil the requirements in IEC 60076-7. With the fans out of operation transformers with cooling type ONAF must be capable of loading with 60 % of the ONAF rated power. Cooling type ONAN transformers shall be prepared for future assembly of fans for additional cooling. This additional cooling must allow a loading with 130 % of rated ONAN current without exceeding the temperature rise limits of SS EN 60076 2. The transformer rated power is not changed and is still referring to ONAN cooling conditions. The loading of three winding transformers (except generator step up units) shall be limited by the winding having the highest rated power. Each of the other two windings shall be capable of carrying its rated power and the other the rest up to the maximum winding rated power. E.g. 63/38/25 MVA or 63/63/0 MVA for a 63/63/25 MVA transformer. Inter-bus transformer may be specified by means of a number loading cases which shall be fulfilled. From these an equivalent rated power in accordance with IEC 60076-1 shall shall be calculated for reference purposes. Inter-bus transformers 400/220 kV and 400/130 kV will during emergency conditions (once during the life time) be subjected to an overload according to Table 4.5, Loading cases for inter-bus transformers for a period of some months. The estimated winding hot spot temperature at such an operating condition must not exceed 130 °C at an ambient temperature of 0 °C if not otherwise specified. For generator step up transformers the loading requirements given in IEC 60076-7 shall not apply but the specified loading cases will be the governing requirements. For generator step up transformers the rated voltage of windings connecting to the generator(s) shall normally be equal to the generator rated voltage(s). Generator step transformers shall in addition be capable of operation at a voltage above 105 % of the rated voltage but not greater than 110 %. At a current K (0 ≤ K ≤ 1) times the transformer rated current the voltage shall be limited in accordance with the following formula:
U(%)=110–5×K2
Bushings, on-load tap-changers and other accessories shall be selected in such way that they can carry currents above the corresponding winding rated current of at least the same amplitude and for the same duration as the transformer itself can withstand. Bushing rated currents must, however, exceed the winding rated current by 20 % (30 % for cooling type ONAN). On-load tap-changer rated currents must, however, exceed the winding rated current by 10% for cooling type ONAN. For built in current transformers refer to Clause 12, Bushing current transformers.
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The transformer neutral and its bushing as well as built in bushing current transformers shall have the same loading capability as the corresponding line terminals (for auto connection the line terminals of the high voltage side). HVDC converter transformer loadings will be derived from the over all plant requirements. 4.8 Neutral point loading 4.8.1 Inter bus transformers If not otherwise stated the neutral points of three limbed auto-connected inter bus transformers (400/220 and 400/130 kV shall be capable of continuously carrying a DC current of 200 A for 10 minutes the transformer operating at its worst loading and at maximum ambient temperature. In case of single phase units or five limbed three phase units the supplier shall state the maximum allowed continuous neutral point DC current 4.8.2 Transformers for HVDC If not otherwise stated the AC side neutral of an HVDC transformer shall be capable of continuously carrying a DC current of 10 A the transformer operating at its worst loading at maximum ambient temperature. 4.8.3 Non effectively earthed transformers If not otherwise stated non effectively earthed neutral points shall be capable of - continuously carrying an AC current amounting to 10% of the rated phase
current and the transformer operating at its worst loading at maximum ambient temperature
- carrying rated phase current for 30 s and no current for 15 min repeated three times every three hours during a 24 h period and the transformer operating at its worst loading at maximum ambient temperature
4.9 Type of cooling Cooling type ONAN is the normal case for transformers rated 25 MVA and below. For higher ratings cooling type ONAN, ONAF or OFAF is to be optimised considering the loss evaluation and the available space. Type OFWF is used only if specified. For type OD.. cooling the same maximum allowable temperature rise as for type OF.. shall apply (Deviation from SS-EN 60076-2, Cl 4.2). Furthermore when disconnecting a fully loaded transformer at max ambient temperature it shall not be required to pump oil through the windings, i.e. no post tripping cooling. 4.10 Sound levels If not otherwise specified the sound power levels in Table 4.7 shall apply:
Max allowable sound level Equivalent two-winding rating
MVA Sound power level – LWA
dB(A) 6,3 65 10 68
Vattenfall Eldistribution Svenska Kraftnät 09-02-06 TR 1-10E rev CTekniska Riktlinjer
Table 4.7: Maximum allowed sound power levels A positive tolerance of +0 dB(A) shall be valid. The sound power level LWA shall be measured in accordance with IEC 60076-10 and shall apply both with and without cooling equipment in operation. For transformers with variable flux voltage regulation sound level measurement shall be performed at the tapping giving the highest core flux density. In case of separately erected cooling equipment maximum allowable sound level will be specified in every single case. The transformer size is equivalent to the high voltage winding rated power. For intermediate sizes linear interpolation shall be used. Factory measured sound power level shall be rounded off to the closest integer value before comparison with the guarantee level. 4.11 Core design As the normal case the transformer core shall be of the three limbed core type. Five limbed core or shell type may be used in special cases if explicitly stated in the inquiry. 4.12 Winding design The manufacturer shall state the depolymerisation number (DP) of the insulation paper used in the windings: - new paper from the paper sub-supplier (actual value) - processed and tested transformer ready for shipping (expected value) Thermally upgraded paper may be used only after written approval from the purchaser. The method of reduction of ageing effects shall be described as well as any negative effects of this upgrading.
Vattenfall Eldistribution Svenska Kraftnät 09-02-06 TR 1-10E rev CTekniska Riktlinjer
23(92)
4.13 Insulation system The tender shall present approximate insulation system dimensions for each winding pair in accordance with the figure below. The insulation is lumped together in a barrier block with radial thickness (X) and spacer block with a tangential width (Y) indicating the relative amount of insulation material in the respective direction in the main duct (duct length = 1 and duct width =1) between two windings. The Barrier thickness X incorporates pressboard cylinders and winding paper distributed across the main duct. The Spacer width Y incorporates the spacers distributed along the main duct.
4.14 Other internal design requirements The transformer shall be designed in such a way that copper sulphide deposition will be prevented. For transformers 500 MVA and above winding wires and bare conductors shall always be equipped with a high temperature varnish layer. 4.15 Alternative designs 4.15.1 Stabilising winding If not otherwise stated or there are special limits on zero sequence impedances no stabilising winding shall be furnished. If requested its insulation level shall be chosen according to its highest voltage for equipment. If a stabilising winding is provided the delta shall be closed and earthed externally to the tank cover. 4.15.2 Auxiliary winding A 400 V auxiliary winding shall be furnished on standardised transformers, for other transformers only if specified.
Vattenfall Eldistribution Svenska Kraftnät 09-02-06 TR 1-10E rev CTekniska Riktlinjer
24(92)
Standardised transformers shall be provided with an auxiliary winding 420/242 V with tappings at -5, 0 and +5%. For transformers having voltage regulation of type VFVV (variable core flux) tappings at -7.5, 0 and +7.5% may be specified. If an auto connected matching transformer is provided this must be designed for a rated supply voltage of maximum 420 V. For standardised transformers the rated power shall be chosen from the following table
Power transformer Auxiliary transformer (MVA) (kVA)
Table 4.8: Auxiliary winding rated power For other transformers the auxiliary power rating is specified in every single case. However, the maximum power will be 400 kVA. 4.15.3 Off-circuit tap changing and change over between system voltages Off-circuit tap changing and change over between system voltages is not the normal case but will be specified if required. 4.16 Other data 4.16.1 Supply voltages for motors, control equipment etc: On-load tap-changer motor operation Normally 110 V dc (in some cases 220 V dc) or 400/230 V ac. On-load tap-changer motor drive control and indication: 110 V ac from an interposing transformer or 110 V dc (in some cases 220 V dc). Cooling equipment motors: 400/230 V ac Cooling equipment control: -operation voltage 230 V ac, single phase -signalling voltage 110 V or 220 V dc Other control equipment: -operation voltage 110 or 220 V dc -signalling voltage 110 or 220 V dc Lighting and heater: 230 V ac, single phase
Vattenfall Eldistribution Svenska Kraftnät 09-02-06 TR 1-10E rev CTekniska Riktlinjer
25(92)
Maximum voltage variation -15% to +10% shall apply at the connection point of apparatuses. 4.16.2 Contact breaking capacity Contacts for external use shall at least have the following breaking capacity if not otherwise specified in the relevant transformer fitting standard (SS-EN 50216):
• 0.15 A at 220 V dc and L/R = 40 ms • 0.30 A at 110 V dc and L/R = 40 ms
4.16.3 Enclosure class and degree of protection Apparatuses and connection boxes shall at least fulfil enclosure class IP45 according to SS-EN 60529 and degree of protection Class I according to SS-EN 61140. 4.16.4 Control equipment insulation levels etc. The following insulation categories in accordance with SS-EN 60664-1 shall apply:
Equipment Over voltage category
Material group
Pollution degree
Terminal blocks IV I 2 Current transformer circuits IV I 2 Motors IV I 2 Other parts IV I 2
Table 4.9: Insulation categories 4.16.5 Disturbance requirements Control equipment, cooling equipment and on-load tap-changer motor drive equipment shall fulfil the requirements set up in SS-EN 61000 5 BUSHINGS 5.1 General For highest voltage for equipment Um ≥ 52 kV condenser type bushings shall be used. Applicable standard is SS-EN 60137. For highest voltage for equipment Um < 52 kV either condenser type or ceramic type bushings may be used. Condenser type bushings may be of either oil impregnated paper (OIP) or resin impregnated paper (RIP) type. However if specified dry type bushings shall be used. The insulator for condenser type bushings may be of either ceramic or polymeric type and will specified in every single case. For voltages ≥ 245 kV polymeric type of bushing (housing) shall be used. Ceramic type bushing shall fulfil SS-EN 50180, SS-EN 50243 or SS-EN 50386. Deviations may be made for the connection details on the oil side but first after written approval from the purchaser.
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26(92)
For each combination of highest voltage for equipment and insulation level only one type of bushing is allowed. Extended bushing turrets may be specified to facilitate future installation of a sound level reduction enclosure. 5.2 Marking Each bushing shall have a rating plate showing the identification, e.g. type and catalogue No. On smaller bushings this can be stamped into the top bolt or the flange or on a separate plate on the transformer. 5.3 Capacitive taps Phase bushings for highest voltage for equipment Um ≥ 82.5 kV shall be equipped with capacitive taps for measuring purposes. The measurement taps shall be connected to a common connection box at service level where they normally shall be short circuited. 5.4 Oil level indicator Bushings for highest voltage for equipment Um ≥ 245 kV shall be provided with oil level indication 5.5 Special requirements for oil-SF6 connection assemblies. The transformer supplier shall provide a detailed description of the oil level and pressure supervision system for the bushings. It is the transformer supplier’s responsibility to make such arrangements that short circuit bridges have no harmful impact on the transformer. The over all responsibility of the interface lies on the transformer supplier. Other requirements such as pressure supervision, expansion chambers, level indication etc are specified in every single case. 5.6 Special requirements for cable connection assemblies. For highest voltage for equipment 82.5 kV and above the requirements given in SS-EN 50299 and SS-EN 50299C1 shall apply. The over all responsibility of the interface lies on the transformer supplier. Other requirements such as cable box with SF6, oil or air etc are specified in every single case. 5.7 Special requirements for encapsulated buses. It is the transformer supplier’s responsibility to make such arrangements that short circuit bridges have no harmful impact on the transformer.
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27(92)
The over all responsibility of the interface lies on the transformer supplier. Other requirements such as interface, short circuit bridges etc are specified in every single case. 5.8 Terminals 5.8.1 General Current carrying connections including screws, nuts and washers necessary for the connection of external conductors are to be provided by the purchaser in case of condenser bushings. The terminals shall primarily be provided with flat terminals (flags) Cylindrical terminals are accepted in those cases were the terminal is a natural termination of the internal conductor arrangement. 5.8.2 Flat terminals The flat terminal shall fulfil the dimension requirements below. To admit the assembly of the current carrying connection there must be a free space of minimum 5 mm between the flat terminal and the apparatus to be connected. The size of the flat terminal shall be selected from the table below:
Size Highest voltage for equipment ≤52 kV >52 kV
2 - 40 400 A - 4 - 75 630 - 1250 A 9 - 125 1600 - 3150 A 12 - 165 4000 A
Table 5.1: Flat terminals 5.8.3 Cylindrical terminals The cylindrical terminal shall fulfil the dimension requirements below. The terminal shall be secured against rotation. The size of the cylindrical terminal shall be selected from the table below:
Size Rated apparatus current Aluminium terminal Copper terminal
30 630 - 1250 A 630 - 1600 A 40 1600 A 2000 - 2500 A 60 2000 - 2500 A 3150 - 4000 A
Table 5.2: Cylindrical terminals 5.8.4 Material Terminals of copper or a copper alloy shall be tin coated to layer thickness of at least 50 µm. Copper alloy sensitive to stress corrosion must not be used.
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28(92)
Terminals of aluminium or an aluminium alloy must not be surface treated. In case of an alloy this shall have the same corrosion resistance as pure aluminium. Aluminium alloy sensitive to stress corrosion, layer corrosion or grain boundary erosion must not be used. Flat terminal of aluminium or an aluminium alloy shall have a hardness of at least HB min 75. 5.8.5 Flat terminal dimensions
75
40
40
Size 2- 40 t≥10, Φ=14
Figure 5.3: Flat terminal size 2-40
75
40
75
40 Size 4- 75 t≥15, Φ=14
Figure 5.4: Flat terminal size 4-75
125
40
40
Size 9-125 t≥35, Φ=14
Figure 5.5: Flat terminal size 9-125
Vattenfall Eldistribution Svenska Kraftnät 09-02-06 TR 1-10E rev CTekniska Riktlinjer
hings may be stated based upon the available spares. If uoted bushings do not comply with the preferred ones spare bushings shall be
OFF-CIRCUIT TAP-CHANGING AND SYSTEM VOLTAGE
s-ction
It shall not be possible to completely loosen connection pieces, screws and nuts.
Figure 5.7: Cylin 5.9 Spare bushings In the inquiry preferred busqincluded in the tender. 6RECONNECTION Change of ratio (+x%, 0, -x%) and reconnection between system voltages (serieparallel, Y-D) shall be made with the transformer not in operation. The reconneshall be made by means of bolted connections accessible through hatches in the cover.
Vattenfall Eldistribution Svenska Kraftnät 09-02-06 TR 1-10E rev CTekniska Riktlinjer
30(92)
7 ON-LOAD TAP-CHANGERS Change of ratio in operation shall be made by high speed on-load tap-changers for
N
e diverter switch shall whenever suitable use vacuum switching technology in
shall be paid to reduce recovery voltage transients on the 0.42 kV
ffect on equipment lier is obliged to take
le mechanically linked indicating for
rating mechanism shall be constructed for local and remote motor operation.
ed.
he drive shall be provided with legible and weather proof labels with arrows for the
mber is connected when making a electrical
tor, readable from the the tap changer. The tap ighest ratio shall
remote and local operation. The tap-changers shall fulfil the requirements in SS E60214-1 and IEC 60214-2. Thorder to minimise the maintenance requirements. Special attention auxiliary system emerging from on-load tap-changer operations. Such transients may
ccur in case of free floating regulating windings when operating the coarse or ochange-over selectors. These transients may have adverse eonnected to the 0.42 kV system and consequently the suppc
measures for their reduction to non harmful levels. If applicable diverter switch oil compartments shall be provided with pressure or oilflow gauges.
he transformer shall be equipped with a legibTdevice showing the position of the diverter and the tap selector. (Not applicable tap-changers with diverter and operating built together in one unit.) 8 ON-LOAD TAP-CHANGER MOTOR DRIVE 8.1 General
he opeT The drive shall be located for an easy operation in service. Contacts for raise and lower shall be electrically and mechanically mutually block One complete operation must not take more than 25 turns at hand operation. The required number of turns shall be indicated on a plate on the drive. The operation time at motor operation must not exceed 8 s. As soon as the drive is in progress this must be indicated and labelled "ÖKAR" (raising) and "MINSKAR" (lowering). Thand operation and also labelled "ÖKA" (raise) and "MINSKA" (lower) at the arrow points. Raising means that a higher tapping nuraise operation or a clockwise operation. The drive shall be provided with a legible position indicaoutside. The indicator shall be mechanically controlled by positions shall be numbered from one and upwards. The h
Vattenfall Eldistribution Svenska Kraftnät 09-02-06 TR 1-10E rev CTekniska Riktlinjer
31(92)
correspond to position No. 1, i.e. in the normal case this will give a higher voltage on
ily movable to any tap osition. In addition each limiting device shall have an electrical and mechanical
it
.2 Functional requirements When
onductors shall be disconnected.
o operate the motor protective switches by hand.
ctive
h is
op. he
hese external contacts are closed the operation cycle
he
eac
length only a single step operation will be carried out, so called step-by-step peration. For another step to be performed the operation pulse must be
Whboth in motor and control circuits for the actual operating direction. The limit
the low voltage side at a higher tap position. The mechanical and electrical limiting devices shall be easpblocking function to prevent harmful operation. For electrically operated single phase tap-changers a zero-voltage in any motor circushall be signalled and operation of the other phases shall be prevented. 8A change of the drive motor polarity must not imply a reversal of the rotation. at stand still all phase c Motor circuit fuses must not be located in the drive unit. The motors shall be protected against overload by motor protective switches. In case of single phase tap-changers the motor protective switches shall be of a design allowing for a common fusing of the three drive motors. It must be possible t The motor protective switches shall be provided with an auxiliary contact which is closed when the switch is open. This contact will be used for signalling at proteswitch tripping. Circuits for motor, control, position indication and heating shall be electrically completely separated.
started cycle of operation shall be completed even if the operation pulse lengtAshorter than the time required for one step. When an over current is passing through the tap-changer the drive motor shall stThis shall be accomplished by means of external breaking contacts in series with tdrive operating circuit. When tshall be completed. W n the operation pulse length is longer than the time required for one step new cycles shall immediately follow until the pulse disappear or a limiting device is
hed, so called multi-step operation. r The drive shall be easily re-connectable so that independent of the operation pulse
odisconnected and a new pulse must be given after completion of the first step.
en the drive reaches either end limit the contacts for electrical stop shall open
Vattenfall Eldistribution Svenska Kraftnät 09-02-06 TR 1-10E rev CTekniska Riktlinjer
32(92)
switches shall have forced mechanical operation and also be independent of any ng force for its operation. spri
he following auxiliary contacts shall be provided:
One making contact which closes as soon as the drive is leaving its rest position
itching is immediately at hand or already under way.
before the actual load switching and which remains closed until the operation cycle is completed. The time during which the
tching time.
The contact is to be used together with over current relay contacts to indicate nd
Contacts for potentiometer transmitter tap position indication.
stand at least 0.3 A continuously.
cts shall be used for tap position indication and for parallel control.
be provided if ecified. If such contacts are not specified future addition of such contacts shall be
SUPERVISORY EQUIPMENT
oval.
y separate ontacts:
T •
and which remains closed until the operation cycle is completed. • This contact will indicate that a sw
• One making contact which closes just
contact is closed shall as close as possible correspond to the critical swi
•
that the diverter switch has been subjected to over current during switching aconsequently calls for an inspection of the diverter switch contacts.
• The potentiometer transmitter shall have as many positions (N) as the number of tappings and N-1 sub resistors. Each resistor shall be of about 10 or 50 Ω with an
dividual spread of maximum 0.5%. in For plus/minus and for coarse/fine tap-changing so called "run through" contacts
ust not indicate separate tap positions. m The potentiometer transmitter shall with The conta Contacts for simultaneous or master follow parallel control shallsppossible.
9The transformers shall normally be provided with the following gauges. These shall
ave a prompt making and breaking function. h In order not to prevent the development of new technologies other configurations
ay be accepted, however, only after written apprm 9.1 Gas and oil actuated relay The gas and oil actuated relay shall be provided with two electricallc
Vattenfall Eldistribution Svenska Kraftnät 09-02-06 TR 1-10E rev CTekniska Riktlinjer
33(92)
• One closing for slow gas formation to be used for tripping. • One closing for heavy gas formation, heavy oil flow and low oil level to be used
service.
ork standing on a ladder or on the platform according to Clause 15.9 lause 4.4.4.
losing at too high and too low oil
il level indicators shall be located at service level (not on the conservator).
aving a high voltage side highest voltage for equipment Um ≥ 82.5 V the oil level indicator shall be provided with remote indication possibility
d at level.
ntly adjustable contacts closing hen the temperature reaches the adjusted value.
ges shall e used for signalling/tripping the others will be used optionally e.g. for control of
he temperature gauges shall be provided with a legible maximum pointer resettable
ter-bus transformers 500 MVA and above and generator step up transformers 75
temauge.
Transformers 75 MVA and above and of cooling type OF, shall if specified, be provided with one bottom oil temperature gauge.
for tripping.
he relay shall be provided with shut off valves as well as a by pass with no shut off Tpossibility in order to facilitate relay exchange when the transformer is in service. Gas sampling and functional testing shall be possible to carry out when the ransformer is in t
The relay shall be located in such a way that a person executing testing or
placement wrecan not reach within the safety distance according to C 9.2 Oil level indicator
he oil level indicator shall have making contacts cTlevel. The contacts will be used for signalling. For transformers having a high voltage side highest voltage for equipment Um ≥ 82.5 V the ok
For transformers hk(potentiometer). A plate showing the oil level as a function of top oil temperature shall be provideservice 9.3 Temperature gauges (thermometers) The temperature gauges shall have four independew The contacts shall be electrically separated. One contact of each of the gaubcooling.
Tfrom the outside.
InMVA and above shall be provided with two temperature gauges for the top oil
perature. Other transformers shall be provided with one top oil temperature g
Vattenfall Eldistribution Svenska Kraftnät 09-02-06 TR 1-10E rev CTekniska Riktlinjer
34(92)
ding temperature gauges (showing winding hot spot temperature) shall be Win
provided as follows (not applicable to stabilizing and auxiliary windings):
e erature gauge in the warmest winding.
ed ure gauge in each winding.
ivalent two winding power
winding average oil.
hall be provided with Pt100 resistors for remote temperature indication
he diverter switch oil compartment shall be provided with an overpressure relay
reaching a pressure (an oil flow) as specified by the manufacturer. In case of more an one oil space individual relays for each space shall be provided.
I slay
9 5 case of OF.. cooling oil flow gauges having contacts closing at too low oil flow
case of cooling type ..WF the following is required for each cooler:
• w
Water flow gauge and meter with one contact closing for a flow above and below
oil out of the cooler ng at a minimum pressure specified by the manufacturer
• Two winding transformers 16 MVA and above and without OLTC shall b
provided with one temp • Two winding transformers 16 MVA and above and with OLTC shall be provid
with one temperat • Transformers with three windings or more having equ
16 MVA and above shall be provided one temperature gauge in each winding. • Generator step up transformers 75 MVA and above shall be provided one
additional winding temperature gauge based upon bottom oil and
• All temperature gauges s
In addition to thermometer pockets for the above gauges there shall be one extra thermometer pocket. 9.4 On-load tap-changer overpressure relay T(alternatively an oil-flow relay) equipped with an adjustable contact closing when
th t hall be possible to perform a function test of the overpressure relay (oil flow
) without disassembly. re
. Cooling equipment gauges and transmitters Inshall be provided. Contact closing shall occur also in case of wrong oil flow direction.
In
Oil flow gauge and meter with one contact closing for a flow above and belosettings specified by the manufacturer
•settings specified by the manufacturer
• Pressure gauge (manometer) for minimum pressure of the
with one contact closi
Vattenfall Eldistribution Svenska Kraftnät 09-02-06 TR 1-10E rev CTekniska Riktlinjer
35(92)
• ter) for maximum pressure of incoming water with one m pressure specified by the manufacturer
e replaced by differential pressure
The pressure gauge contacts are intended for signalling/tripping
For each cooler Pt100 transmitters shall be provided for
- oil out of each cooler
ers) and transformers for HVDC (category D) shall be equipped with an
isture.
eral p in two
nd rate cables.
ut any leakage the oil having a temperature
f
ater coolers shall be of double wall/tube design with leakage detection.
ll if requested take part in the design of the site as to cooler cation and thereby also guarantee that the necessary cooling air will be supplied
according to clause 3.2.
Pressure gauge (manomecontact closing at a maximu
• The pressure gauges (manometers) may b
gauges (differential manometer) with one contact closing when the pressure difference between oil and water is falling below a value specified by the manufacturer
• •
- oil into each cooler
- water into each cooler - water out of each cooler
9.6 On-line dissolved gas monitor Transformers 63 MVA and above, all generator step up transformers (category C transformon-line dissolved gas monitor indicating at least a weighted sum of some of the combustible gases and moisture in the oil. There shall be at least 4 – 20 mA signals for remote indication of gases and mo The power supply to the monitors shall be 110 V or 220 V dc. 10 COOLING EQUIPMENT 10.1 GenSystem (inter bus) transformers 500 MVA and above and generator step uransformers 75 MVA and above shall have the cooling equipment dividedt
groups. The two groups shall be electrically separate, have its own protection and control a
e supplied through sepab For cooling type OF.. all components having circulating oil must withstand an
ternal overpressure of 0.3 MPa(e) withoinof 90 °C. Water cooler tubes etc (cooling type ..WF) shall withstand an internal overpressure o0.5 MPa(e). W The manufacturer shalo
Vattenfall Eldistribution Svenska Kraftnät 09-02-06 TR 1-10E rev CTekniska Riktlinjer
36(92)
In case of separately mounted coolers the necessary cabling and piping as well as ssembly shall be included in the supply.
l r
ded.
e oil pumps by an auxiliary contact of the ansform
If not ot erwise stated the co quipment p supply shall be taken from the auxiliary inding when applic The ac power supply shall be arranged in accordance AFS 1993:10, Cl 1.6.3 “Frånkoppling av kraftkällor” onnection wer sources”). The control shall normally have three switches with a handle for operation mode selection. Two for the fan g
he switches shall be labelled:
hes FRÅN (off)
a 10.2 Cooler control equipment In the normal case the top oil thermometer will control the coolers. Spare terminablocks for connection of another type of cooling control such as a current relay fourrent control or a breaker auxiliary contact shall be provic
Itrt shall be possible to control th
er breaker.
h oling e ower w able.
(“Disc of po
roups and one for the pumps.
T
Fan switc TILL (on) VAKT t2 (gauge t2) VAKT t3 (gauge t3) Pump switches FRÅN (off) TILL (on) VAKT t1 (gauge t1) HK (breaker auxiliary contact)
temperature setting t1<t2<t3 Table 10.1: Cooling selector
In case of sub division of the cooling equipment the number of switches will be a
ultiple of three. m Each motor shall have its own motor protective switch having both manual and automatic operation. The motor protective switch shall have at least one auxiliary contact which is closed when the switch is open. This contact will be used for signalling at protectivetripping.
switch
ction.
ach motor protection and each contactor (auxiliary relay) shall be provided with its own miniature circuit breaker (MCB).
The motor protective switches must not be provided with under-voltage prote E
Vattenfall Eldistribution Svenska Kraftnät 09-02-06 TR 1-10E rev CTekniska Riktlinjer
37(92)
The complete control circuit shall be protected by a circuit breaker and be proviwith voltage supervision. Provisions for disconnection in case of fire or risk of fire shall be provided. Staggered switching may become necessary if fo
ded
und advantageous from the imensioning point of view.
dimension main and group circuit breakers as well as feeder ables taking into consideration that these can not cause any undesired trippings at a
motors have stopped and the voltage returns and all the mperature gauges have their contacts closed.
or transformers without an auxiliary winding or in case of coolers fed from the
purchasers local pow imum value and uration of the total starting current at simultaneous start of all motors as above.
Taking the selectivity into account information shall also be given on which size and type is applicable for the main circuit breaker through which the complete cooling equipment is fed. The principal cooling equipment circuit is given in the principal cooling circuit diagram below.
d In case of cooling equipment power consumption higher than 20 kW half the number of fans must be delayed in order to limit the total starting current. For transformers with an auxiliary winding feeding the cooling equipment the manufacturer shallcsimultaneous start of all pump and fan motors. This might be the case after an outage when thete
Fer supply the manufacturer shall state the max
d
Vattenfall Eldistribution Svenska Kraftnät 09-02-06 TR 1-10E rev CTekniska Riktlinjer
38(92)
Figure 10.2: Principal cooling circuit diagram
Vattenfall Eldistribution Svenska Kraftnät 09-02-06 TR 1-10E rev CTekniska Riktlinjer
39(92)
11 CONTROL EQUIPMENT DESIGN design
ansformer terminals shall always be located in a separate cubicle.
edance
l equipment supervisory equipment may be connected in
r vibrations.
ormally be
1.2 Ventilation, heating and lighting n for insects
ripping into the boxes or the cubicles a dripping protection or a d roo ll be provided.
p-changer drive and for the cooling equipment ll be provid and an earthed 230 urrent
rcuit breaker event condensation s
ich requires extra heating to secure its tion at – 4 the heatermostat. A provided to give an alarm before the perature d it of safe equipme
all be provided a possibility to feed the heating and lighting in the on load tap ger moto net from the station local power supply.
rmal insulation, if provided, shall be of incombustible material.
Heaters shall be protected against unintentional contact.
11.1 General The control equipment shall be assembled functionally and be subdivided as follows: - Supervisory equipment - On-load tap-changer motor drive Cooling equipment -
- Current transformers
urrent trC t shall be possible to arrange separate cubicles for the connection of an impI
protection to the auxiliary winding (matching transformer cubicle) and for connections to the bushing capacitive taps. n case of small scale controI
the on load tap changer motor drive. The control equipment shall be designed and assembled to withstand occurring ransformet
oxes and cubicles shall be located for easy access. Cables shall nB
connected from below why the underside shall be at least 600 mm above the erectionplane. 1Boxes and cubicles shall have draining and ventilation. As protectioopenings shall be provided with e.g. nets having a mesh size of about 1 mm.
o prevent water dTprotrude f sha Boxes and cubicles for the on-load tasha ed with lighting V socket with a residual cci . A heater to pr hall also be provided. Boxes or cubicles contaiunc
ning equipment whf 0°C ambient temperature
shall be shall be controlled by a
ther n extra thermostate limtem rops below th nt function.
It shchan r drive and control cabi The
Vattenfall Eldistribution Svenska Kraftnät 09-02-06 TR 1-10E rev CTekniska Riktlinjer
40(92)
11.3 Term3.1 General ubicles sh
rminal blocks.
Terminal blocks shall be suitable for the connection of conductors having a cross ction of 1 - 10 mm².
l bloc r internal circuits are to be selec the manufacturer.
cables com outside shall be connected to the one side of the terminal e other one. Maximum two conductors may be
nected to o
e terminal blocks shall be located for easy access. For the connection of incoming ductors m ong the complete terminal row shall be vided.
e terminal b ithin each group.
omponents shall be provided with individual markings for easy identification in circuit diag
3.2 Disposition of terminal groups in the control cabinet main cabi ks should be functio ally grouped like the following ple dispos ion
inal up
otes
inal blocks 11.All c all have the necessary number of 8 mm wide slide link type disconnect te
se Terminal blocks for the motor power supply shall have a size governed by its purpose. Termina ks fo ted by All ing from thegroups and all the internal cables to thcon ne terminal. Thcon inimum 100 mm free space alpro Th lock labelling shall begin on 1 w All cthe ram. 11.The net terminal bloc nsam it
Termgro
Use N
X1 | X10
Power supply and Auxiliary supply
ower supply to have lower numbers than auxiliary power Incoming feeder to have lower
Pumps to have lower numbers than fans. Signalling and indication in group X50
X51 | X53
OLTC gauges
X54 Gas and oil actuated relay X55 X56
Oil level indicator
X57 Remote cooler control E.g. transformer breaker
Vattenfall Eldistribution Svenska Kraftnät 09-02-06 TR 1-10E rev CTekniska Riktlinjer
41(92)
X|X
this shall be connected to this group 61 Temperature transmitter If supply from current transformer 70
X|
91 Gauges for oil-SF6 bushings
X99 Table 11.1: Control cabinet terminal blocks
3.3 Disposition of terminal groups in the OLTC motor drive OLTC ca l blocks should be functionally grouped like the following ple dispos
inal
11.The binet terminasam ition
Termgroup
Use Notes
X1
Power supply
X2 Auxiliary power supply Heating, lighting, excluding tap position indication
X3 perating circuits Including operating voltage OX4 gnalling circuits SiX5 osition indicator, potentiometer X6
P
X7 Position indication X8 | X11
Position switch of type break before Make
X12
5
osition switch of type make before reak
| X1
PB
X16 Follower switch, for parallel control X17 Follower contact X20
21 End limit switches
XX22 Gauges in main control cabinet X26 | X30
Spare
X51 | X53
OLTC gauges
Table 11.2: OLTC motor drive terminal blocks
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11.3.4 Disposition of terminal groups in the current transformer cubicle 11.3.4.1 Disposition The terminal blocks shall be grouped as follows:
Terminal group
Us
e
X11 Core No. 1 for all three phases for the highest voltage X No. 2 for all three phases for the highest voltage 12 Core X13 Core No. 3 ... X14 Core No. 4 ... X15 Core No. 5 ... X21 Core No. 1 for all three phases for the next highest voltage X22 Core No. 2 ... X23 Core No. 3 ... X24 Core No. 4 ... X25 Core No. 5 ... X31 Core No. 1 ... .. . ... ... X for the highest voltage 101 Core No. 1 in the neutralX102 Core No. 2 "- X201 Core No. 1 in the neutral for the next highest voltage X202 Core No. 2 ... X301 Core No. 1 .... .. . .. . ...
T 11.3: CT cubicle terminal bloc 11.3.4.2 Terminal numbering for current transformers around phase bushings
able ks
Vattenfall Eldistribution
1
2
3
4
5
6
7
8
Phase R, 2S1
Phase S, 2S1
Phase T, 2S1
Examp Core No he highest voltage windle: . 2 of t ing
Phase R, 2S3
Phase S, 2S3
Phase T, 2S3
X12
Figure 11.1: Phase CT terminal block numbering
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11.3.4.3 Terminal numbering for current transformers around neutral bushings
Vattenfall Eldistribution
1
2
3
4
Neutral, 1S1
Neutral, 1S2
Example: Core No. 1 for the neutral of the next highest voltage winding
X201
tral CT terminal block numbering
normally only be required around phase and neutral
urrent transform ratur hall ful equirements, however, ratio, acc arking y the tra manufacturer. Of redundancy reason of the relaying cores in each phase shall be connected to the termi
currents he current transformers shall be designed for a rated primary current according to
the following table. The hig rrent sh he value closest above 1.0 times the power transformer rated current.
(A) (A)
Figure 11.2: Neu 12 BUSHING CURRENT TRANSFORMERS 12.1 General Current transformers will bushings for Um ≥ 82.5 kV. C ers for tempe
urac d me indication s is c n b
fil these rns ery an hose form
s onenal box by a separate cable.
12.2 Electrical data 12.2.1 Rated primary T
hest rated cu ould be t
Phase bushing Neutral bushing
150 - 300 300
300 - 600 600
500 - 1000 1000
1000 - 2000 2000
1500 - 3000 3000
2000 - 4000 4000
Table 12.1: Rated bushing CT currents
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12.2.2 Rated secondary currents rrent shall be 1 A. In some cases 2 A will be used in line with the
continuous thermal current sformers the rated continuous thermal current shall be
or other transformers the rcurrent for transformers 10 12.2.4
he transformers shall be capable of withstanding a primary rated short-time current for 1 sec of at least 15 times the rated primary current, however, not higher than 50
ulation levels he current transformers shall fulfil the requirements in SS-EN 60044-1.
signed with three or four or possibly five cores:
y winding which shall be electrically completely e other windings.
Rated secondary cuold company standard. 12.2.3 Rated For generator step up tran1.05 times rated current F ated continuous thermal current shall be 1.8 times rated
0 MVA and below and 1.5 for larger ones.
Rated short time currents T
kArms. 12.2.5 InsT 12.2.6 Cores and windings 12.2.6.1 Phase bushings 12.2.6.1.1 General The current transformers shall be dea Maximum four relaying cores b Maximum two metering cores Each core shall have its own secondarseparated from th 12.2.6.1.2 Accuracy classes
elaying cores shall fulfil the following requirements: R
Rated current (A)
Rated output (VA)
Accuracy class
<500 10 5P20 ≥500 20 5P20
Table 12.2: Relaying accuracy requirements for line terminal CT:s.
he requirements:
Rated output
(VA) Accuracy
class
Metering cores will be specified from case to case, however, minimum one of tfollowing
7,5 0.2Fs10 7,5 0.2SFs10
Table 12.3 Metering accuracy requirements for line terminal CT:s.
Vattenfall Eldistribution Svenska Kraftnät 09-02-06 TR 1-10E rev CTekniska Riktlinjer
45(92)
12.2.6.2 Neutral bushings 12.2.6.2.1 General The current transformers shall be designed with two cores. Each core shall have its
ically completely separated from the ther winding.
e cores sha
Accuracy
own secondary winding which shall be electro 12.2.6.2.2 Accuracy classes Th ll fulfil the following requirements:
uperposed magnetization may not be used, but turns correction without any
2.3 Design
2.3.2 Test terminals ,
shall be made in the common connection
12.2.6.3 Accuracy limit factor and instrument security factoAs a common designation to the accuracy limit factor (ALF) and the instrumensecurity factor (Fs) the concept "overcurrent number (n)" will be used in these guidelines. 12.2.6.4 Test conductor The cores shall be provided with a common 35 mm² test conductor, by meawhich current transformer testing can be carried out without magnetizing and lo 12.2.6.5 Superposed magnetization Ssignificant superposed magnetizing effects can be accepted. 112.3.1 General The current transformers shall fulfil the requirements of the SS-EN 60044-1. 1One end of the test conductor shall be connected to an additional terminal clampmarked M, in the terminal box on the transformer top and the other end to the transformer tank.
2.3.3 Secondary terminals 1Earthing of the secondary terminalscubicle.
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13 AUXILIARY WINDING 13.1 General The auxiliary equipment is subdivided into: a. Auxiliary winding terminals and main fuses
. Load switch bc. Auxiliary transformer (matching transformer) d. Fuses for local power supply e. Fuses for cooling equipment . Fuses for impedance protection (for Um f ≥ 82.5 kV)
ng terminals. Main fuses.
the terminals. The neutral terminal shall be earthed to a flat rminal welded to the transformer tank.
uses and winding terminals shall be provided with a single phase insulating ithstand arcing. The
hall be provided with a legible plate reading "Får
nsidered
5 times the auxiliary winding rated current at cos(ϕ)=0.7(ind.).
får n att underimpedansskydd avställts" (Breaking is not allowed unless the
iliary transformer shall be provided with an enclosure with a hinged and bolted front cover. Oil insulated auxiliary transformer shall be hermetically sealed and be provided with contact protected terminals.
g. Auxiliary power cable box
3.2 Auxiliary windi1The auxiliary winding terminals shall be fused outside the transformer tank in immediate vicinity ofte Fenclosure of incombustible material which also must wequipment shall be enclosed in a cubicle with a hinged and bolted front cover.
he terminal / fuse cubicle sTendast öppnas i spänningslöst tillstånd" (Only to be opened when off circuit).
he main fuses are a short circuit protection for the transformer and are coTas a part of it. 13.3 Load switch At service level there shall be an encapsulated load switch having the breaking
pacity 1.2ca The load switch cubicle shall be provided with a hinged and bolted front cover. The load switch cubicle shall be provided with a legible plate reading "Brytningj ske utae
impedance protection is blocked). 13.4 Auxiliary transformer Dry type aux
Vattenfall Eldistribution Svenska Kraftnät 09-02-06 TR 1-10E rev CTekniska Riktlinjer
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13.5 Fuses for local power supply, impedance protection and ooling equipment
The auxiliary winding voltage shall be tapped from a separate distribution board assembled on the tank in close vicinity to the auxiliary transformer and be provided with one to three groups for local power supply, a possible cooling equipment and a possible impedance protection. All groups shall be fused by knife (blade) type fuses. Those for impedance protection which have rated current 6 A are required only for transformers with the high voltage winding highest voltage for equipment Um ≥ 82.5 kV. All knife type fuses shall be connected to the bus system in a way that will minimize the risk of a short circuit. Cables shall be provided and connected to the impedance protection and cooling equipment cubicles. Terminals for cable protective earthing shall be furnished for each fuse group. 13.6 Local power supply connection box On the fuse box for local power supply a separate connection box for the connection of cables shall be furnished. The underside of the cable box shall be at least 600 mm above the erection plan. There shall be a free space for the purchaser’s cables and cable boxes. 13.7 Neutral conductor The auxiliary equipment shall be provided with a through-running neutral conductor, i.e. in case of a full wound auxiliary transformer its two neutrals shall be connected to each other. 13.8 Protective earth conductor and protective earthing. A through-running and unbroken protective earthing conductor shall be furnished. In the main fuse box this conductor shall be connected to the neutral earthing terminal. Protective earthing o ning protective arthing conductor shall be made. Please note that serial earthing is not allowed.
c
f each enclosure or cubicle to the through rune
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13.9 Auxiliary power circuit connection diagram
Vattenfall Eldistribution
L1
r
L2
s t
L3
n
LOCAL POWERSUPPLY
AUXILIARY WINDING TERMINALS
MAIN FUSES
N
IMPEDANCE PROTECTION (if applicable)
L2
L1
N
L3
PE
COOLING EQUIPMENT (if applicable
MATCHING TRANSFORMER
LOAD SWITCH
INSULATING SINGLE PHASE ENCLOSURE
BOLTED TAP CHANGING
Figure 13.1: Auxiliary power circuit diagram
NTROL CABLES d possibly wire armoured cable.
les must not come into contact with the ch a way that they do not become an
14 POWER AND COPermanently laid cables shall be of screened type an To prevent excessive heating the cabtransformer cover and they shall be laid in suobstacle for water drainage.
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Cables on the cover and other horizontally laid cables shall be provided with a using steel wire armouring.
Clips and cable straps shall be of stainless steel. Cable sheath and possible protective earthing conductor shall be earthed in both ends of the cable.
he cable bending radius o n times its own diameter.
ds for
shall be all welded and all welding work shall be performed by licenced elders.
t Um ≥ ll
t ismantling of the cover
5.5.1 General
ng at half e tank height One for sampling at the tank bottom
treading protection, however, this is not required when
T
f any cable must not be below te
All cables and cable cores shall be provided with individual markings at both enthe identification in the circuit diagram. The cables markings outside boxes and cubicles shall be of stainless steel. 15 TRANSFORMER TANK 15.1 General All weldsw Bell type tanks are generally not permitted. 15.2 Vacuum safety For transformers with the high voltage winding highest voltage for equipmen82,5 kV the tank must withstand a full internal vacuum. A vacuum proof tank shahave a marking indicating this. 15.3 Cover Transformers with highest voltage for equipment Um ≥ 82,5 kV shall have the coverwelded to the tank. 15.4 Hand holes Hand holes shall be provided to facilitate the exchange of any bushing withoud 15.5 Valves 1Butterfly valves and ball valves are preferred 15.5.2 Sampling valves One to three oil sampling valves shall be provided: A One for sampling at cover level B One for sampli thC
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The number of sampling levels are chosen as follows:
Highest voltage for equipment Sampling level (kV)
145 – 420 A, B, C 82.5 A, C ≤52 C
Table 15.1: Oil sampling valves
ll valves shall be located at the tank bottom level. For the valves A and B anA
the arket.
rmers shall be rovided with two extra valves, Connection No. 100 or 200, intended for the
cuit design and the selection of material will be anded over to the manufacturer for approval.
cuit shall be approved by the manufacturer. The ansformer guarantee shall be valid without any limitations due to the external heat
5.6 Pressure relief valve
s must not contain any asbestos.
times without
external pipe connection from the sampling level shall be furnished. The valve dimension shall be Connection No. 20 with an internal thread R 3/4". 15.5.3 Valve for on-line oil analysis One valve for shall be provided for the connection of an on-line dissolved gas analyser. Valve dimension will be specified considering available analysers onm 15.5.4 Valves for extra heat exchanger Transformers 100 MVA and above and all generator step up transfopconnection of heat exchangers for station heating. The heat exchanger system will normally be designed and assembled by the purchaser, but the external oil cirh At site the external oil cirtrexchanger system. 1The transformer tank should not be equipped with any pressure relief valve. 15.7 Gaskets The gasket It shall be possible to disassemble and assemble hatches a couple of exchanging the gaskets and keeping unchanged tightening function (hatches for connections and inspection).
5.8 Erection, Lifting devices, Transport. 1On the transformer tank there shall be a durable marking of the centre of gravity during transport. Transformers 20 MVA and below shall be designed for dragging and will normally be placed on oak beams.
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Transformers larger than 20 MVA and having a total weight up to and including 60
ns will normally be placed on wheels.
n supports or oak planks but for oving on rails wheels may be used and shall if specified be included in the supply.
luded.
y marked attaching plates for jacks e erection plane.
hen placed on supports in addition to the jacking plates there shall be sufficient number of jacking positions on the tank bottom. These shall be so located that the
heels, wheel holders or bogies do not interfere with the handling of jacks.
ransformers having a transport mass 60 tons and above shall be possible to s, hanging on brackets between the beams. If
port wagons is preferred.
Transport brackets shall be provided by the manufacturer. Transformers must not be transported hanging in yokes (loops) between the transport wagon side members. For the transport two independent impact recorders shall be provided. One shall be installed inside the tank. The manufacturer shall before the start of the transport state the maximum allowed
he setting of the detection limit shall be agreed upon between the manufacturer and e purchaser.
n of the impact recorders shall regularly be checked during the ansport.
5.9 Gas and oil actuated relay inspection platform m for
ents of the Swedish Work Environment Authority. It shall be possible to attach the ladder to three of the platform sides. A separate ladder with slip protection may accepted but only after written agreement. The platform shall be constructed with a floor of lattice type and have raised borders (slip protection). Furthermore bars or chains shall be provided at the ladder opening.
to Larger transformers will normally be placed omSupports shall always be inc Wheel holders or bogies shall be designed for longitudinal and lateral movement. As to track gauges refer to Clause 15.10, Track gauges. The transformer tank shall be provided with clearlminimum 300 mm above the rail or th W
w
Ttransport by Green Cargo wagonpossible the choice of two different trans
accelerations in XYZ-direction. Tth The operatiotr 1If requested transformers 63 MVA and above shall be provided with a platfor
spection of the gas and oil actuated relay. The platform and the ladder shall fulfil inthe requirem
Vattenfall Eldistribution Svenska Kraftnät 09-02-06 TR 1-10E rev CTekniska Riktlinjer
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The location of the gas and oil actuated relay is dealt with in Clause 9.1. Permanently assembled ladder shall be provided with protections against falling down in accordance with AFS 2000:42, 61§ 15.10 Track gauges
5.10.1 General The track gauges shall als ion on steel or concrete
eams or oak planks.
1o apply in case of transformer erect
b 15.10.2 Longitudinal movement Track gauge 1435 mm
1435
ck gauge 1435 mm 1)
Figure 14.1: Longitudinal track gauge
15.10.3 Lateral movement Alternative A – tra
1435
Figure 14.2: Lateral track gauge A
lternative B – Track gauge 2940 mm 1), possibly a centrally located support wheels A
Vattenfall Eldistribution Svenska Kraftnät 09-02-06 TR 1-10E rev CTekniska Riktlinjer
53(92)
2940
Figure 14.3: Lateral track gauge B
Alternative C – Track gauge 4000 mm with a centrally located support wheel
4000
Figure 14.4: Lateral track gauge C Alternative D – Track gauge 2×1435 or 2×2500 mm with 4000 or 5000 mm centre distance between track pairs.
1435 / 2500 1435 / 2500
4000 / 5000
Figure 14.5: Lateral track gauge D Note 1: For 70 and 130 kV transformers the track gauge 1435 mm shall be chosen if possible.
Vattenfall Eldistribution Svenska Kraftnät 09-02-06 TR 1-10E rev CTekniska Riktlinjer
54(92)
16 CORROSION PROTECTION AND SURFACE TREATMENT k
Normally the manufacturers painting procedure is accepted, however, only after written approval. 16.2 Connection boxes, cubicles and OLTC motor drive 16.2.1 Alt 1: Painting The external painting system shall comply with the requirements based on SS EN ISO12944 corrosivity category C3. In case of costal influence or industrial areas category C4 will be specified. Category C5 will be specified only in extreme cases in immediate sea vicinity and very heavy polluted industrial areas. Normally the manufacturers painting procedure is accepted, however, only after written approval. 16.2.2 Alt 2:Hot dip galvanising Hot dip galvanising shall be made in accordance with SS-EN ISO 1461. Hot dip galvanised surfaces must not be painted. 16.3 Screws etc All screws, washers and nuts of dimension M8 or less shall be of stainless steel in accordance with SS 14 2324 and SS-EN 10088-3 or of another from the corrosion point of view equivalent material. Screws of dimension M10 and larger shall be of stainless steel or hot dip galvanized. Screws and nuts shall be waxed in order to prevent seizing. 16.4 Coolers For cooling type ..AN and ..AF the coolers shall be hot dip galvanized in accordance with SS-EN ISO 1461.
or cooling type ..WF t contact with the ansformer oil.
be painted.
16.1 Transformer tank, OLTC tan
F the coolers must not have copper in directr Hot dip galvanised surfaces must not
Vattenfall Eldistribution Svenska Kraftnät 09-02-06 TR 1-10E rev CTekniska Riktlinjer
55(92)
17 EARTHING 17.1 Principal earthing diagram
Vattenfall Eldistribution
Control Cubicle CT Cubicle
PE PE Earth CT
N
PE
INSULATED FROM TANK AND CT CUBICLE
e 17.1: Principal earthing diagram.
ings having highest voltage for equipment Um ≥ 170 kV
hall ottom) shall terminate at the same level as
ther tank earthing points. To avoid tank damages due to fault currents the bus shall be insulated from the tank. For the connection of earthing cables by cable lugs the neutral bus lower end shall be provided with two holes Φ 14 mm with a vertical c/c 40 mm distance. As to fault currents the neutral bus shall be dimensioned in the same way as the transformer.
Figur
17.2 Neutral point earthing For direct earthing of windthe transformer shall, if not otherwise stated, be provided with a neutral bus assembled on the tank. The end of the bus connected to the neutral point (top) sbe disconnectable and the other end (bo
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17.3 Protective earthing 17.3.1 Transformer tank For the protective earthing of the transformer tank two earthing terminals diagonalocated close to the tank bottom shall be provided. The earthing cable comprises a
lly
ntre shall be
contact will be obtained
onnection cubicles and cabinets shall have a protective earthing to the transformer
urrent transformers shall be earthed to a common internal earthing terminal
mm².
7.3.4 Auxiliary power equipment
the
pment All metallic pieces not welded to the tank shall be earthed to the tank through visible earthing links or equivalent devices. 17.4 Core earthing The r earthing shall be individually earthed in an external earthing box located at ground level.
few-wire copper conductor, 95 mm² for highest voltage for equipment Um ≥ 82.5 kV and 185 or 240 mm² for higher voltages. The terminals shall be flat with four holes, Φ 14 mm, having a vertical ce
contact surface distance of 40 mm and a horizontal one of 50 mm. The protected against corrosion in a way that a good electricalafter assembly. 17.3.2 Connection cubicles and control cabinet Ctank through a visible earthing connection. Cinsulated from the cubicle. This terminal shall also be accessible on the outside of thecubicle and be designed for the connection of an earthing cable of at least 25 17.3.3 On-load tap-changer The tap-changer cover and/or tank shall have a protective earthing to the transformer tank through a visible earthing connection. 1Refer to the Clause 12 on auxiliary power equipment. 17.3.5 Separately erected cooling equipment Each cooler support shall be provided with one earthing terminal identical with ones for the transformer tank. 17.3.6 Other equi
co e and core clamping
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57(92)
18 OIL AND OIL SYSTEM
d/or severely hydro
tart energising temperature (LCSET) shall be – 40 °C.
e higher than 10% (v/v).
tion ed.
w two oil samples from the transformers for among others PCB check (even
he following documentation shall accompany each delivery: of origin and refining location
ct specification with data according to SS-EN 60296 verification proof of a non corrosive oil with respect to sulphur
information on:
• health hazard
zard
dling
ed oils: • NYNÄS NYTRO 10XN • SHELL DIALA DX
18.1 Oil quality requirements The oil must be of naphthenic base and be solvent refined an
eated. trThe oil must fulfil the requirements for inhibited oil (group I in accordance with SS EN 60296) and contain at least 0.3% (kg/kg) of an oxidation inhibitor of type di-tert butyl-parakreosol (DBPC).
he lowest cold sTThe oil must not be added any pour point depressants. The oil must not be added any gas absorption additives. The limit to verify the PCB content must be 0 ppm. If an oil sample withdrawn at the delivery contains 2 ppm or more the oil delivery will not be accepted.
he total aromatic content must not bT It should be noted that the kinematic viscosity at -30°C must not be higher than 800 mm²/s (Deviation from SS-EN 60296). The manufacturer shall present an oil specification for approval. In the specificathe type of base, country of origin and refining place shall be clearly stat In connection with the factory acceptance tests the manufacturer shall, if specified, withdraif the oil will not be shipped with the transformer). Sample containers will be provided by the purchaser. TA test certificate indicating country B HPLC "finger print" (HPLC = High Performance Liquid Chromatography) C produD E
• fire fighting precautions • decomposition products
• first aid • personal protection • environmental ha• destruction • storage and han• transport classification
Examples of approv
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58(92)
18.2 Oil system The main conserhumidity to and a
vator shall be provided with a rubber bag or membrane to prevent ir access. Other solutions except nitrogen cushion may be accepted
VA but first after written approval.
er diverter switches operating in oil shall have an oil compartment ompletely separated from the transformer oil and provided with a separate
into the transformer must not exceed 0.3% (by olume). This will normally be fulfilled by using a rubber sack having a diffusion rate
² rubber and year at 20°C. The aging properties of the
8.3 Conservator nsformer and at steady state
il shall at steady state not t +40°C ambient temperature and fully loaded transformer.
mounted conservators shall have expansion couplings in its connection ipes.
g for oil filling shall be provided with a case with an internal thread.
all be a shut off valve between the gas operated relay and the conservator.
ather shall be provided with a dehydrating breather with a hydraulic
dehydrating breather shall be of maintenance-free type.
he air dryer shall be located at service level and the drying substance must be visible
l be provided with a label showing the colour change when the rying substance is becoming humid.
lause 15.5.2
for transformers ≤ 40 M On-load tap-changcexpansion space. After oil filling the leakage of airvof less than 50 l air per mrubber material shall be presented. 1At - 40°C ambient temperature, off circuited tracondition the oil level must not drop to such a level that the oil level indicator no longer will show any level reading. Furthermore the ooverflow a Separately p The openin There sh 18.4 Dehydrating breThe transformer guard. If not otherwise stated the Talong the complete length of the dryer. The air dryer shald 18.5 Oil sampling Refer to C 18.6 On-line monitoring Refer to Clause 9.7
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19 MARKING 19.1 Plates 19.1.1 Rating plate
se
IEC/EN/SS-EN-standard uipment for all windings
be provided (may be combined with the oil circuit diagram
bushings
y be combined with the
-1, Clause 9
nd also:
service interval
The rating plate shall contain the information according to SS-EN 60076 1, Clau7.1 - 7.2 and also: - - highest voltage for eq- the purchaser’s reference No. 19.1.2 Diagram plate
A diagram plate is required for transformers having Um ≥170 kV and for all three inding transformers. w
9.1.3 Accessory plate (for Um ≥ 170 kV) 1
If specified a plate shall plate) showing the following accessory information: - location - size or type designation - purpose The following accessories shall be included: - - gauges - valves - venting valves - hatches for reconnection thermometers -
9.1.4 Oil circuit diagram (for Um ≥ 170 kV) 1If specified an oil circuit diagram shall be provided (maccessory plate). a
er and motor drive plate19.1.5 On-load tap-chang
The rating plate shall contain the information according to SS-EN 60214a- insulation level - maximum rated through current (Ium) - contact length of life -
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19.1.6 Bushing current transformer plate and marking e
etc. shall be used).
- P2, where P1 is closest to the transformer. The test conductor terminal arking, M, shall correspond to P2.
plate eside the power transformer rating plate, or as a part of it, or inside the connection
e th SS-EN 60044-1. Note here that the current transformer
rial No. as well as calculated (not rated) values of the winding resistance (R) and n) shall be specified.
plate, or as a part of it, or inside the connection fixed, distinct diagram plate showing the current
nal marking. The separate main data for the
shall be a plate showing pping position and position of connection links etc.
ation.
ach individual accessory shall be provided with a plate showing the purpose as well
tion cubicles shall have plates showing the purpose.
ided with plates such as F1, F2 ..…
plate with a diagram or a table showing the oil level as a function of ambient l be provided. Even
e signalling levels shall be indicated.
The secondary terminals shall be marked according to SS-EN 60044-1 (Thalternative 1S1, 1S2 The secondary terminal marking shall correspond to a fictious primary terminal marking P1 m 19.1.6.1 RatingBcubicle there shall be a permanently fixed, distinct rating plate which shall contain thdata in accordance wisethe over current factor (
he rating plate shall in other respects fulfil the requirements for the transformer. T 9.1.6.2 Diagram plate 1
Beside the power transformer ratingubicle there shall be a permanentlyc
transformer connection and termidifferent cores shall be clear from the plate. The diagram plate shall in other respects fulfil the requirements for the transformer. 19.1.7 System voltage re-connection plate At the location of the system voltage reconnection theretaThe transformer diagram plate shall show the same inform 19.1.8 Other platesEas clear identification. Connec Pumps shall be provided with plates such as P1, P2 .... Fans shall be prov Labels showing the direction of rotation of fans shall also be provided. Atemperature and loading conditions in steady state condition shalth
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61(92)
20 INFORMATION IN THE BID
addition to SS-EN 60076-1, Annex A the manufacturer shall in his bid submit all or elsewhere in this
ocument.
of it the bid will not be taken into onsideration.
atalogues, pamphlets, summaries etc. shall be provided with clear reference to the
sions guaranteed with a tolerance of +200 mm
ations and type of inding. In case of subdivided windings the percentage turns distribution shall be
ical
e and power frequency tests
pare parts list including unit prices
20.1 General Inthe information asked for as specified below, in the inquiry d In case of missing information or partsc Ctendered equipment. 20.2 Bid content Description of the manufacturing plant Reference list and failure statistics from the last five years Description of the testing facilities Outline drawing in 3 copies with - outer dimen- bushing locations and air clearances - outer dimensions and tank dimensions Swedish railway coach transport drawing in 3 copies proofing that the transformer will not exceed the Swedish railway transport sections. Data compilation as per Appendix 2 properly completed Connection diagram If specified a winding diagram showing internal winding locwshown If specified a winding diagram showing the voltage stresses, at impulse tests and at power frequency tests, between physical windings and between windings and core/yoke/earth If specified a winding diagram showing size and direction of maximum dynammechanical stresses for each winding. The corresponding fault case shall be indicated
est connection diagram for impulsT Oil specification S
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List of all deviations from the inquiry, this document and the standards and specifications referred to
embly
pe test certificates from short-circuit tests on similar units
uality Management System
g, on and environmental impact are fulfilling
t documents, standards, specifications and
cuting
anufacturer as a reference for the purchaser or
spection and test plan TP) containing a summary of all the inspections and tests which shall be performed
of and inspection documents.
the
The deviations shall be accompanied with clear references If specified a time schedule for drawings, diagrams, control and inspection plans for the manufacturing, tests and ass Type test certificates on units identical in rating and construction Ty 21 QUALITY ASSURANCE 21.1 Quality and Eco Management Systems The manufacturer shall in his tender describe his Q(QMS) and Eco Management System (EMS) to ensure that the transformers in all respects such as design, supply of materials, choice of material, manufacturintesting, service, maintenance, documentatithe requirements set up in the contracregulations. The quality management shall be based on and in relevant parts fulfil the requirements in SS-EN ISO 9001 and SS-EN ISO 14001. The manufacturer is responsible to all his sub suppliers establishing and exequality management systems on their own. 21.2 Quality manuals Complete quality manuals describing the execution of all the elements of the quality
stems shall be available with the msyhis representative. The manual shall be written in English. 21.3 Quality inspection. Inspection plans The manufacturer shall for each transformer establish a main in(Iduring the manufacturing, factory acceptance testing, final assembly and commissioning. It shall be clear from the inspection plan where inspection activities shall be performed, the parties to be present and inspection plans in force and distributiontesting The main inspection and test plan shall be approved by the purchaser before beginning of the manufacturing.
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The purchaser or his representative shall have the right to take part in any inspeor test and shall also be informed of th
ction e result as specified in the inspection
ocuments.
n
he purchaser or his
2 DESIGN REVIEW MVA
cordance with
uirements and to indicate areas where special
fy any prototype features and to evaluate their reliability and risks
after the completion of the electrical design, the
n.
changes in the design may be required.
3.1 General
eeks before commencement of the
d The purchaser or his representative shall also at any moment have the right to, without any advance notice, make a follow-up of an arbitrary inspection, manufacturing step or test at the manufacturer’s or the sub supplier’s plant and thealso be informed of the result. Inspections and tests performed in the presence of trepresentative will not imply any limitation of the manufacturer’s responsibility. 2For all category B through D transformers and category A transformers 100 nd Um ≥ 145 kV and above design reviews shall be conducted in aca
the guidelines in Cigré Reports No. 204 and 209. If requested design reviews may be conducted even for other transformers.
he objective of the design review is T -to ensure that there is a clear and mutual understanding of the technical equirements r
-to verify the system and project reqattention may be required -to verify that the design complies with the technical requirements -to identi The review is preferably held preliminary outline drawing, the rating plate drawing and before the start of and manufacturing activities. The review shall be held at the manufacturer’s plant and it shall be considered as confidential. Its purpose is not to give possibilities to make changes in the desig
owever, should it be evident that the manufacturer is not fulfilling specified Hrequirements necessary 23 FACTORY ACCEPTANCE TESTS. FINAL INSPECTION. 2The factory acceptance tests shall be witnessed by the purchaser or his representative and a notice shall be submitted at least two wtests. At the acceptance tests the transformer shall be assembled as for service, i.e. complete with conservator, coolers, auxiliary transformer, supervisory equipment etc. This means that even oil-SF6 bushings must not be replaced by corresponding oil-air
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bushings. Deviations from this requirement may be made, however, only after written approval from the purchaser. Type tests on a representative transformer may be referred to if the type test report is
se
ordance with IEC 60076 if not
ts below also be tested in accordance with IEC 61378-2.
n-load tap-changers shall be tested in accordance with SS-EN 60076-1, SS-EN
-EN 60044-1 if not
down to 0°C are accepted from practical
n
ory. The latest calibration
ll apply
and test reports
ing copies of draft test reports shall be handed over the purchaser’s inspector immediately after completion of each test. The inspector
not older than five years and is submitted together with the bid. If this is not the catype tests shall be made. The meaning of “representative” is explained further in the NOTE to SS-EN 60076-1, Cl 3.11. These requirements apply also to on-load tap-changers, bushings and built in current transformers. 23.2 Standards. Testing specifications. Factory acceptance tests shall be performed in accspecified otherwise below. Transformers for HVDC (Category D transformers) shall in addition to the requiremen Bushings shall be tested in accordance with IEC if not specified otherwise below. O60214-1 and IEC 60214-2 if not specified otherwise below. Current transformers shall be tested in accordance with SSspecified otherwise below. 23.3 Testing environment During site tests ambient temperatureseasons. r
23.4 InstrumentatioAll measuring equipment shall be of at least class 0.2. Analogue watt meters giving a full deflection for a power factor of 0.1 may be of class 0.5. The equipment shall be calibrated at least once a year at a measurement laboratcurves shall be available at the test location. The equipment shall in addition be provided with visible markings showing the last calibration date. 23.5 Tolerances
the bid, order and contract it may be stated that the guaranteed losses shaInwithout tolerances. This refers only to the calculation of bonus and penalty. For impedances there may be individually specified tolerances.
3.6 Test results223.6.1 General A preliminary test report includtoshall have the right to receive a draft test result copy as soon as a part test is finished.
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Routine test reports for bushings, on-load tap-changers, auxiliary transformer and pe test
st location.
port shall be available at the purchaser’s office.
ype test certificates referred to shall un-requested be sent to the purchaser without
ype test certificates more than five years old cannot be accepted without special
he routine test certificates shall include, in addition to the routine test results, the
icate Current transformer data
3.7 Routine tests
gs and licable.
e
be made in accordance with IEC 60076-8, Cl 7.7.2.
current transformers shall be presented to the inspector without request. Tyreports for the other equipment shall be available at the te The result from all routine, type and special tests shall be compiled in a document together with the test program as well as a possible non conformance report. Please note that if type tests have been performed on another transformer or its accessories
e corresponding type test reports shall be included. th At the latest three weeks after the factory acceptance tests three copies of the test re 23.6.2 Bushing current transformers Tany delay. Tagreement. Tfollowing information: A The date and reference No. of the type test certifBC The parameters n and Rct (from the type test) for each core for the determination of the over current factor at different burdens.
The purchaser's reference number DE The current transformer serial No. 223.7.1 Measurement of winding resistance (SS-EN 60076-1, Cl 10.2) Resistance measurement shall be made in the principal and the extreme tappinlso in the lower-limit full power tap when appa
If requested further measurements in maximum four taps shall be measured. In case of winding(s) reconnectable between different system voltages resistance measurements shall be performed for all connection possibilities. 23.7.2 Measurement of impedance voltage, short circuit impedance and load loss (SS-EN 60076-1, Cl 10.4) Loss and impedance measurement shall also be made at the lower limit full power tap when applicable. For auto connected transformers the power shall be fed to the higher voltage and thlower shall be short circuited. In case of auto connected transformers with a third winding the loss allocation shall
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In case of winding(s) reconnectable between different system voltages loss
easurements shall be performed for each voltage level.
, Cl 10.5)
d below.
70, 80, 90, 100, 105, 110
d according to the three watt meter method and orrection for voltage wave form shall always be made.
n measurements are performed at room temperature no temperature correction
easurement, i.e. its no-load loss shall be included. As ngle phase no-load current measurements
all e e
10.7)
indings
or all auto connected transformers and if not otherwise stated for non-auto
hen measuring the short circuit zero sequence impedance the neutral current and phase currents shall be registered.
ic ts, the star point of the transformer can be loaded up to rated current.
ge and active power consumption
m 23.7.3 Measurement of no-load loss and current (SS-EN 60076-1Measurement of no-load loss and no-load current shall be made at 100 and 105 % of rated voltage for transformers 10 MVA an For larger transformers the measurements shall be made atand 115 % of rated voltage. The measurements shall be performec Wheshall be made. If an auxiliary transformer is furnished this must be connected during the loss m
reference for future field tests three sib performed feeding each phas with 230 V. sh
23.7.4 Measurement of zero sequence impedance (SS-EN 60076-1, Cl This section applies only to three phase transformers. The test shall be performed as a routine test on all YN and ZN connected won three phase transformers. Ftransformers the zero sequence impedance shall also be measured for a short circuited high or low voltage winding in pairs. Wthe sum of the The zero sequence impedance shall, if apllicable, be measured in the principal and
e extreme tappings. th For transformers without a D connected winding the measurements in no-load shall be performed from a very low (+0 A) neutral current up to as high current as possible (approximately 30% of rated current). In cases where a counter magnetflux exis At all tests, neutral current, phase to phase voltashall be measured. From these measurements impedance, reactance and resistance shall be calculated in both ohms per phase and as a percentage of the base
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impedance. The zero sequence impedance is assumed to be a series connection of a
60076-3, Cl 11)
complete auxiliary power supply system. 3.7 2 test (SS-EN 60076-3, Cl 12)
m=170 360 kV respectively
23.7 3 076-3, Cl 12) For three phase transformers the test shall always be carried out as a three phase test.
iation from SS-EN 60076-3):
Um/√3
to fall below Um/√3.
d, however only after ritten approval from the purchaser.
rmed as a routine test on neutral terminals having sulation level LI170-AC70 and above.
e .
reactance and a resistance. 23.7.5 Dielectric tests 23.7.5.1 Separate source voltage withstand test (SS-EN In case of auxiliary power equipment a separate source test shall be performed on the
2F
.5. Induced AC voltage or transformers with the high voltage side highest voltage for equipment U
and 245 kV a three phase induced voltage test with 275 and between phases shall be performed.
.5. Induced voltage test and partial discharge measurement (SS-EN 60
The following PD guarantee levels shall apply (Dev
• 300 pC when U2 =1.5×Um/√3 • 200 pC when U2 =1.3×
Measured partial discharge levels and the inception voltage, Ui, as well as the extinction voltage, Ue, shall be recorded and presented in the final test report. Neither of Ui or Ue is allowed The normal partial discharge detection method shall be of type broad band measurement, but narrow band measurement may be permittew 23.7.5.4 Lightning impulse test on a neutral terminal (SS-EN 60076-3, Cl 13.3.2) Lightning impulse shall be perfoin 23.7.6 FRA Transformers 100 MVA and above and all GSU and HVDC transformers shall bsubjected to a sweep frequency response analysis (FRA) fingerprint measurement 23.7.7 Pressure testing The transformer tank and the coolers shall be subjected to a 12 h over-pressure test on the liquid surface corresponding to an oil column equal to the internal tank height. 23.7.8 On-load tap-changer operation test In addition to the tests in SS-EN 60076-1 the requirements on multi-step operation and end limits according to Clause 8.2 shall be verified by operation tests.
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23.7.9 Bushing current transformers
he following insulation resistances shall be measured:
ulation resistance measurement
• between all windings connected together and ground (tank + core)
ssories
nd
tested with 2 kV 50 Hz for 1 min.
in
tests surement
and
.8.2 Light
e impulse te a routine test on all other identical ansformers in the same delivery without any extra cost.
type test
A power frequency test shall be carried out on the test conductor at 3 kVrms, the windings and other current transformer parts being earthed. 23.7.10 Core insulation resistance measurement T
• Core to tank • Core to yoke clamps • Yoke clamps to tank
3.7.11 Winding ins2
The following insulation resistance and polarisation index measurements shall be performed:
• between each winding and the other windings connected together and grounded
23.7.12 Tests and inspections on acceInspections shall be carried out to assure that the transformer is equipped with all the accessories and equipment stipulated in contract documents and these guidelines athat they operate as intended. Each complete control equipment shall be voltageMotors for the on-load tap-changer motor drive shall be subjected to a test with at least 1.5 kV 50 Hz for 1 min. The insulation resistance between electrically separated circuits or between conductor and ground must exceed 2 MOhm measured with 500 V DC. 23.7.13 Painting inspection Examination of the corrosive protection and the surface treatment requirementsClause 16 shall be performed.
3.8 Type223.8.1 Zero sequence impedance meaTo be performed as a type test for a high voltage side rated power 16 MVAbelow. The test extent is specified in Clause 23.7.4 23 ning impulse test (SS-EN60076-3, Cl 13) If a failure occurs during this type test or if the test is not approved of other reasons th st shall be carried out astr Reference to a type test where a failure or another non approval has occurred with subsequent repair or other measures will not be accepted as a type test but amust be performed.
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23.8.3 Temperature rise test Temperature rise test shall be performed with full total loss and with maximum rated urrent for each winding (also for multi winding transformers) or in accordance with
the test certificate required total loss and currents as well as the ones measured
hen determining oil temperature rise both method a and b according to SS-EN
ecorded and calculated temperatures and temperature rises shall be presented with
ination shall be presented in e test report. All measuring points shall be included and it shall also be clear which
ce the first
t proceed at least 20 min for cooling pe OF.. and 10 minutes for cooling type ON...
type OF.. cooling pumps and fans shall be running after the test power isconnection.
rature rise test be librated to show winding hot-spot temperature. All necessary parameter settings
to show winding hot-spot based on bottom oil
e test
ed in the factory and at room temperature.
r
st for 8 hours at a load corresponding to 100 % of
ca specified loading case. The assumptions shall be reported in the test certificate. Induring the test shall be stated. W60076-2 may be used. Rone decimal place in the test report. In the final summary integers shall be used. Complete curves for oil and winding temperature determthmeasurements are deemed to be erroneous and consequently deleted. The extrapolation method shall also be stated. When switching off from rated current to determine the warm resistanreliable reading must have been obtained within two minutes from current interruption. The resistance measurement musty In case of d Winding thermometers shall in connection with the tempecashall be presented in the test report.
or generator step up transformers 75 MVA and above the additional winding Fthermometer shall be calibrated temperature. 23.8.4 Overload temperature risTo verify the loadability at emergency operation the following alternative temperature tests shall be perform a. A temperature rise test for 20 hours at a load corresponding to 90 % of the "Peak load / Emergency load " case in Table 4.5, Loading cases fo inter bus transformers b. A temperature rise te the "Peak load / Emergency load" case in Table 4.5, Loading cases for inter bus transformers together with direct winding hot spot measurement by means of fiber optic transmitters.
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During the test thermovision temperature scanning of the tank shall be performed. shall be made.
ur, e first at the beginning of the test.
cturer shall in the test program state the limits for an acceptable gassing
e b the
uration will be halved at a room temperature of 36 °C.
the determination of oil and winding temperatures, the test will be carried out in
d level measurement (SS-EN 60076-1, Cl 8.1.3 d) To be performed as a type test on transformers having the high voltage winding
ighest voltage for equipment Um≥ 82.5 kV.
s
location of microphones the measured sound pressure as well as the equency analysis shall be reported in the test certificate.
ynamic short circuit withstand test. MVA and below.
load tap changer connection with the mechanical endurance test (SS-EN 20214-1, Cl 5.2.5.1) the
tance verification for polluted conditions
le 4.4 the insulation may be verified by hod (section
hich corresponds to the polluted
tor be verified by means of a Dry
conditions on the Swedish west coast orresponds to salt layer of 0.15 mg/cm2. The test method is described in
Appendix1.
Documentation by means of photographs Samples for the analysis of gases dissolved in the oil shall be taken every fourth hoth The manufarate.
the winding hot spot temperature reaches 140 °C during the test alternativIftest shall be interrupted. At room temperatures above 30 °C the duration of the test alternative a may be reduced after written approval from the purchaser. The basic rule is that the test d Inthe same way as for the conventional temperature rise test.
3.8.5 Soun2
h A frequency analysis with a step factor of 1.25 (one third octave band) shall alwaybe made. For each fr 23.8.6 Thermal and dSuch a test may be specified as a type test for transformers 40 23.8.7 OnInfunction at - 40°C shall be verified. 23.8.8 Bushings creepage dis23.8.8.1 Ceramic type insulator As an alternative to creepage distances in Tabmeans of a functional test in accordance with IEC 60507, salt fog metthree). The amount of salt shall be 40 g/l wconditions on the Swedish west coast. 23.8.8.2 Polymeric type insulaFor polluted conditions the creepage distance shouldSalt Layer (DSL) method. The pollution c
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23.8.9 Bushing current transformers
t at rated continuous thermal current.
3.8.9.2 Verification of no-load impedance instrument security factor and accuracy
l be plotted to determine the actual over current ance.
he secondary winding resistance (Rct) shall be measured and corrected to 75°C.
e
12.5.b the actual accuracy limit factor shall be
n=ALF=Iexc/Isn
mperature rise test at 110% of ted voltage.
shall be tested in accordance with SS EN 61000 4 4
ransformer ready for operation st shall be carried out before taking the transformer in
equency response analysis (FRA) nd polarisation index measurement urement
ce measurement (if bushings has been removed during transport)
23.8.9.1 Temperature rise test The temperature rise test shall be carried ou 2limit factor A complete no-load curve shalnumber (n) and for verification of the no-load imped T In addition to IEC 60044-1, Cl 11.6 the actual instrument security factor shall bcalculated as
n=Fs=Iexc/Isn In addition to SS-EN 60044-1, Cl calculated as
23.8.10 Inspection and testing of accessories Contactor and relay coils shall be subjected to a teraThe control equipment terminalsClass 3.
4 SITE TESTS 224.1 Tests on tMinimum the following site teoperation 24.1.1 Transformers 100 MVA and above and all GSU and HVDC units Oil quality test •
• Dissolved gas analysis (DGA) • Frequency dielectric spectroscopy fingerprint (FDS)
Sweep fr• • Winding insulation resistance a• Core insulation resistance meas• Winding resistan• Bushing CT ratio and no-load current characteristic check (if CT:s have been removed during transport) • 230 V single phase no-load current measurement • Operational tests on ALL accessories
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24.1.2 All other transformers
Dissolved gas analysis (DGA) nt
emoved during transport)
and no-load currenransport)
• 230 V single phase no-load current mon ALL accessorie
nd above and all GSU and HVDC units • Extended oil quality test after 12 and
1, 3, 6, 12 and 24 month 24.2.2 All other trans
Extended oil quality test after 24 months in operation
4.3 Site test certificates a
t to be added to the instruction manual.
manufacturer will jointly settle the hold points.
t. The intenance must be
pamphlets may be in English approval from the purchaser.
• Oil quality test • • Core insulation resistance measureme• Winding resistance measurement (if bushings has been r • Bushing CT ratio removed during t
t characteristic check (if CT:s have been
easurement s • Operational tests
24.2 Tests in service 24.2.1 Transformers 100 MVA a
24 months in operation • DGA, after s in operation
formers • • DGA after 12 and 24 months in operation 2The result from the site tests as well as the site test program shall be compiled inocumend
25 TIME SCHEDULES After the transformer has been ordered the manufacturer shall submit a time schedule for the following activities 1 Documentation 2 Manufacturing and testing 3 Transport 4 Erection and commissioning For item 1 the purchaser and the Items 2-4 will be decided by the manufacturer considering the date of commercial operation. 26 DOCUMENTATION 26.1 General All of the documentation shall be in Swedish to the utmost possible extendocumentation required for erection, assembly, operation and main Swedish. However, test reports, catalogues andprovided a written
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26.2 Tender documents Refer to Cl 20.2 26.3 Documents for approval The following documents shall be provided for approval:
1 pies of outline drawings with binding outer dimensions
dule
month after order 3 co
3 copies of the first time sche3 3 copies of binding outline drawings, diagrams
and plates months after order
1tests
and test plan (ITP) with dates
month before factory acceptance 3 copies of inspection
1 copy of complete final documentation A complete
documentation t the delivery 3 copies of the approved
Table 26.1: Documents for approval Documents for approval shall be supplied in PDF format by electronic mail as well s paper copies.
of drawing ceipt.
hen delivering the final documentation (in PDF format) one additional drawing set on CD shall be supplied. For computer produced drawings (CAD) two sets of CD:s with format AUTOCAD shall be submitted. Extensions in accordance with the system WECAD or MECAD are preferred. In this case original drawings shall be submitted as paper copies. Examination and approval of the drawings, diagrams and documentation by the purchaser does not lead to any confinements in the suppliers responsibility. 26.4 Instruction manual The instruction manual shall normally be supplied in three copies one of which shall be available at the purchaser’s office at the latest three weeks before the beginning of the factory acceptance tests. The instruction manual shall in principle be compiled as follows: - Lead sheet with purchaser’s and manufacturer’s reference No. - Data sheet (according to Appendix 2, Compilation of Technical Data) - Dimension / Outline drawing with equipment / accessory list - Circuit diagram with equipment/apparatus list - Control cabinet - Current transformers - Bushings
a The purchaser has four weeks for approval, counting from the date re W
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- On load tap changer w- Cooling equipment
ith motor drive
uipment and other accessories
rmation for all included chemical products
single phase on-load tap-changers.
t shall be legibly marked.
- Oil circuit diagram - Supervisory eq- Transport - Erection / Assembly - Oil specification and information in accordance with Clause 18.1 - Operation and maintenance instructions - Diagnostic maintenance Product and safety info-
- Other information - Test reports - Photographs of the active part and complete transformer In each section there shall be a summary of included drawings (with information on latest revision) and also the main data of included components A summary of all included components (list of apparatuses / equipment list) such as thermometers, on load tap changer, motor drive, pumps, fans etc. shall be provided. Type designations, ratings and a clear identification shall also be provided. For the bushings and current transformers their location shall be stated (serial No. and phase). The same applies to In submitted catalogues and pamphlets the actual componen
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27 Appendix 1 27.1 THE DRY SALT LAYER (DSL) POLLUTION TEST METHOD 27.1.1 Scope This test method is applicable for the determination of the power frequency
ithstand characteristics of line and station class insulators (ceramic, glass,
d
e of a system: Highest value of operating r.m.s. voltage (Us) which
for equipment : Highest phase-to-phase voltage (Um) for which the
erating voltage across the insulation: Um/√3.
pecific creepage distance: The minimum nominal creepage distance divided by the highest r.m.s. voltage for equipment, Um. Salt Deposit Density (SDD): The amount of salt (NaCl) in the deposit on a given surface of the insulator divided by the area of this surface, expressed in mg/cm2. Equivalent Salt Deposit Density (ESDD): The amount of salt (NaCl) that, when dissolved, gives the same conductance as that of the natural deposit removed from a given surface of the insulator divided by the area of this surface, expressed in mg/ cm2. Test severity: The time of exposure to the wind-born salt particles in the DSL test. Site Pollution Severity (SPS): The ESDD value exceeded by not more than 2 % of the measurements of the average value, recorded over an appreciable period of time – i.e. one or more years – on a vertical mounted reference insulator comprising either a string of cap and pin units or a porcelain long rod insulator.
.
wpolymeric) to be used outdoors and exposed to polluted environments close to thesea coast on A.C. and D.C. systems with the highest voltage of the system ranging from 72 kV to 800 kV. 27.1.2 Definitions Test voltage: The r.m.s. voltage with which the test object is continuously energizethroughout the test.
ighest voltagHoccurs under normal operating conditions.
ighest voltageHequipment is designed in respect of its insulation as well as other characteristics which relate to this voltage in relevant equipment Standards. Under normal service conditions specified by the relevant apparatus committee this voltage can be applied continuously to the equipment.
aximum opM S
Site Pollution Severity Class: Classification of the pollution severity at a site, from very light to very heavy, as a function of the SPS, according to Draft of IEC 60815-1
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27.1.3 General description of the DSL test method
t stand phase
humid salt particles from a salt injection system are lown towards the test object using high-speed fans. The test object is exposed to
vel.
osed to steam fog that is ently blown towards the test object. The duration of the wetting phase is fixed to
te
is lly accepted in laboratory pollution tests.
The DSL test method determines the ability of an insulator to withstand a specific environmental severity at the operating voltage level of the insulator. The DSL tescomprises of two parts or phases, the deposit phase and a wetting or withseparated by a period in which the insulator is allowed to dry. During the deposit phase finebthe wind-blown salt for a pre-determined time to give the required pollution leThe duration of the deposit phase can vary between 20 to 60 minutes and the insulator is energised during this time. During the wetting phase the energised test object is expg100 minutes. The energization of the test object is selected as close as possible to the expected service stress. The DSL method is usually run in the form of a withstand test. This means that if noflashover occurs during three consecutive tests, the test object has passed the test. If only one flashover occurs a fourth test shall be performed and the insulator passes the test if no flashover occurs during the last test. The test set-up is illustrated in Figure 27.1
Figure 27.1: Test set-up of DSL in a climate hall
Both A.C. and D.C. tests are possible. The method is equally suitable for composias well as for ceramic insulators. It is suitable for line insulators and apparatus insulators. Several investigations show that the repeatability of the DSL methodbelow 6 % which is genera
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27.1.3.1 Deposit phase During the deposit phase an air-flow, created by a blower array, is used to deposit thpollutants in the form of humid salt particles to the
e test object. The blower array
omprises a series of electrical fans, installed in a cabinet to improve the t
its purpose is to suspend salt particles in the airflow established in the boratory (see Figure 27.1).
l insulator testing station has dicated that a realistic wind speed during the deposit phase is in the order of 5 m/s.
speed there is a remarkable increase in the salt-in-air density called “white
aps” which produce the humid salt particles in the air.
tionality” of the
boratory, the humid salt particles are generated by a zles with a
toward the test bjects as in the salt-fog test. Its purpose is rather to suspend humid salt particles in
e blower array. The relative humidity in the test chamber is maintained at 80±2 % to establish optimal conditions for
insulator. An additional nozzle ramp
E
to the pollution severity specified.
ded service voltage during the whole ms
ely as possible. After the deposit phase the voltage is switched off and the or is allowed to dry.
The DSL uses a wetting method that gives optimal wetting of composite insulators. Wetting by droplets colliding with the insulator surface is more effective than wetting through condensation. This is because the polymeric material of composite insulators tends to adjust quickly to the ambient temperature. This leads to a smaller temperature difference between the ambient and the composite insulator than for a porcelain insulator. The smaller temperature difference inhibits condensation. A fog with small droplet size e.g. steam, is more effective in wetting polymer insulators completely than one with larger drop size e.g. cold fog. The wetting phase lasts for 100 minutes and the acceptance criterion is the same as for the Salt Fog test as described in IEC 60507.
cdirectionality of the air-flow. The salt spray is, however, not directed towards the tesobject as la Measurement of the salt-in-air density at a coastainIt was found that at this because the wind is then strong enough to break up the waves to the soc Pollution measurements at coastal sites normally show a variation in the pollution deposit, with a higher deposit on the side facing the sea. This “direccoastal pollution is imitated by blowing salt particles towards one side of the test object during the test. In the lasalt injection system. This system is built up with standard IEC 60507 nozreduced salt-water flow rate. The salt spray is, however, not directedothe airflow generated by thduring the deposit phasethe attachment of the pollution particles to the producing a clean water fog is used to control the relative humidity in the test hall tothe value 80±2 %.
he test severity of the DSL is quantified by the time of exposure to the wind-born Tsalt particles. Salt Deposit Density (SDD) measurements on reference string or IEEtype porcelain cap and pin insulators according to IEC, or any other type specified by the user are used to calibrate the exposure time The test object is energized to its intendeposition phase to mimic the service conditions of the insulation during salt storas clos
sulatin 27.1.3.2 Wetting phase
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27.1.3.3 Normative references ces in
e text, constitute provisions of this specification. S-EN 60507 Artificial pollution tests on high-voltage insulators to be used on a.c.
C 60815-1 Guide for the choice of insulators under polluted conditions – Part 1:
n line shall be tested.
gth as e test object is used for the calibration of the pollution severity.
et up for the salt deposition with the same test parameter settings as for the test objTh i et SD 2. This corresponds to the SPS level in the Scandinavian coastal regions 0. 272727.1.4.1.1 Determination of duration of deposit time Th alues according to Ta f the pollution is determined fo D 0.15 m ulator. The SDD is taken as the e in le and bottom positions of t d on d bottom side of the disc and on the wind side and lee side as well. 27.Th ing to Table
h test voltage is set to Uas the deposit time.
The following normative documents contain provisions that, through referenth
Ssystems.
IEDefinitions, information and general principles. 27.1.3.4 Test specimen One circuit breaker assembled on the productio 27.1.3.5 Reference tests A reference IEEE cap and pin insulator of approximately the same arcing lenthThe reference insulator is s
ect. e salt deposition time s set to get the targ D of 0.15 g/cm
.1.4 Test procedure .1.4.1 Deposit phase
e reference insulator is set up according to Figure 1 and the v voltage ible 1. The test s set to Um/√3. The duration of the deposit time o
t SDr the targe g/cm2 on the reference ins
mean value from thre sulator discs,per an
at the top, middhe insulator chain an the up
1.4.1.2 Pollution deposit e test object is set up according to Fi
on test object gure 1 and rd the values acco
27.1. T e m/√3. The time determined in section 27.1.4.1.1 is taken
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27.1.4.2 Wetting phase The test set up is rearranged for the wetting phase according to Figure 27.2.
Figure 27.2: Setup of test equipment and the test object during the wetting period of
the DSL test. During the wetting phase, steam-fog is gently blown – at a speed of 0.1-0.5 m/s- towards the test object. The test parameters are set according to Table 27.2. The test object is energized with the test voltage Um/√3 during the whole wetting phase. The duration of the wetting phase is 100 minutes. The voltage is shut off and the test objects is rinsed free from pollution with fresh water with a conductivity less than 100 µS/cm and let dry. Then two consecutive DSL tests are run starting with salt deposit according to section 27.1.4.1.2. 27.1.5 Test Conditions
Parameter Test condition Relative humidity 80±2 % Temperature 20± ºC
Ambient conditions
Air pressure To be noted Wind speed at test object 5.5±1.5 m/s Distance of test objects to the fans 4 m Test voltage Um/√3 Duration of pollution deposit phase 20-60 min.
Water salinity 50 g/l Flow rate 8 nozzles, each at 2.5 l/h Nozzle type Acc. to IEC 60507 clause 8 Nozzle air pressure 700±50 kPa
Salt injection
Time of deposition 60 min Flow rate 10 nozzles at 6 l/h Water injection Nozzle air pressure 700±50 kPa
Target SDD on reference insulator 0.15 mg/cm2 Table 27.1: Test parameters at the deposit phase
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Parameter Test condition Nozzle type Acc. to IEC 60507 clause 8 Number of inlets 4
Steam
Steam intensity 0.035-0.045 kg/m3h Wind speed at test object 0.3±0.2 m/s Test time 100 min
Table 27.2: Test parameters at the wetting phase
criteriot object passes the test if no flashover occurs during a series of three
e insulator then passes the test if no flashover occurs (Acceptance criterion
ces .S. E re l. "T -Sal met abor
ollutio test- for oll ts re ity ar n of ield and la oratory re lts, XIII I ernationa
posium on H gh Voltage Engineerin , Netherla ds 2003.
b J. of insulators with respect to polluted conditions”, IEE Proc.-Gener. Transm. Distrib., Vol. 151, No. 3, Ma
27.1.6 Acceptance n The tesconsecutive tests. If only one flashover occurs, a fourth test shall be performed and thaccording to IEC 60507). 27.1.7 Referen
•C ngelb cht, et.a he Dry t-Layer hod, a l atory p n method marine p ution: I peatabil nd a compaSym
iso f b su nt l i g n
•C.S. Engel re t, R. Hart gs, Lun ist, “Sta dime gch in dqu tistical nsionin
y 2004.
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28 Appendix 2
TA N F W NSF RSE
der s Statio
28.1 DA COMPILATIO OR PO ER TRA ORME 1 GEN RAL
PoInquiry / Or n
Tenderer / Man facturer efere i ) Typ ionu R nce ( Suppl er e designat
2 NETW
ORK DATA
Network kV Short circuit po werfrom resp network MVA
Reference voltage kV Relation X0/X+ - Parallel connected xfo on sides X-marked -
3 RATINGS Three phase design desigSingle phase n no of units Stabiliz ing windingWinding II I III Rated voltage kV Rated power MVA Tapping range % Connection mode - 4 INSULATION LEVELS Winding I I I I IIHighest vquipment
oltage for , Um
kV eRated withst.voltages Lightning impulse kV Switching impulse kV Power frequency kV Air clearances phase-phase mm phase-ground mm 5 LOAD LOSS Windings I/II Ratio kV Reference power MVA
Load loss kW Impedance voltage %
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Windings Ratio kV Reference power MVA
Load loss kW Impedance voltage %
Windings Ratio kV Reference power MVA
Load loss kW Impedance voltage %
Note: The impedance between a stabilising winding and all other windings shall always be stated! 6 NO-LOAD LOSS i
regulated windipp OLTC n principal tapping and At rated ta ing voltage and
ng at OLTC in 1,00×Ur voltage
pos min tagpos
1,05×Ur max vol e
No-load loss kW No -load current % Method of voltage variation
constant voltage flux (CFVV) variable flux (VFVV)
7 CORE DESIGN
core type winding bs on all lim s limbs withou indings t w shell type Flux density at no load and O als ULTC in principal position (with two decim ) at 1,0 × r Limb T, yoke T, shell / side
limb T
8 SOUND L
ax sound POWER level measured in accordance with IEC in any OLTC position tolerance +0 dB(A)
EVELSGuaranteed m ( - transformer with /without coolers in operation / dB(A);
LWA - cooling equipment including pumps ( if d
Lseparate) B(A); WA
9 BUSHINGS Winding / Terminal number Manufacture r Bushing type - OIP = oil impregnated paper - RIP = resin ated
aper impregn
p- C = cerami
c
Insulator typ e
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- C = ceramic - P = polyme ric
Rated current A Rated voltag kV e Pollution class ) (I, II, III Nominal creep age distance mm
Oil level indicator Capacitance ta p
Terminal capacitance box for taps Type designations kV terminal inal kV term inal kV term kV terminal kV terminal inal kV term 10 TAP-CHANGER
On-Load Tap-changer (OLTC) Off-Circuit Tap-Changer (OCTC) Bolted connection under cover Manufacturer Maximum rated through current Ium A Type designation Rated through current Iu A Location Insulation level LI – AC KV
oil type diverter switch va um type diverter switch cu Operating mechanism Manufacturer Quantity pcs Type designation
Parallel o eration. Method : p simultaneous, master-follow Position transmitter potentiometer οhms per step others Supply voltages motor V DC AC
contactors V position indicators, DC AC
heater V AC W 11 CURR Ratio (A)
ENT TRANSFORMERS Core Accuracy cl ed output n / sec. Resistance
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/ kV phase / kV phase / kV n utral e / kV neutral Manufacturer 12 AU TRANSFORMER Manufacturer Type designation
XILIARY
Rated voltag tio / e ra V Rated kVA Connection mode power Air insulated Oil insulated Oil insulated, sealed tank type Integrated with main transformer
13 COOLING EQUIPMENT
oling Type of co ONAN ONAN/ONAF OFAF ODAF OFWF To be by the supplier optimised
Cooler location on the transformer on wall brackets on concrete shelf on separate support supports / brackets included others:
Oil system ps on the oil side each group mp(s) in each group parallel grou cooler(s) in puFan arrangement
horizontally blowing, vertically blowing, vertical suction Co Fan data oler (Radiator) data ma manufacturer nufacturer type designation type designation number of coolers (radiators) number of fans pcs pcs cooling capacity per cooler at K
e rise kW fan speed r/min
average oil temperatur
oil pressure drop per cooler bar air flow per fan m3/s power requiremen kW t per fan Oil pump data Water system manufacturer max water flow pe l/s r coolertype designation min water flow pe bar r cooler oil flow per pump l/s water pressure dro oler bar p per copower requirement per pump kW
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Cooler losses total cooler power consumption kW Po ps Control voltage wer supply for pum and fans
400/230 V f m auxiliary winding ro 230 V AC, others: from station network Signalling vo ge lta
110 V DC 220 V DC others: Oil and water meters and gauges
oil flow gauges included (OF..) w uges included (..WF) water flo ga oil pressure gauges includ (ed ..WF)
absolute pressure differential pressure e e gauges included (..WF)
water pr ssur
absolute pressure differential pressure M M Type designation eter / Gauge anufacturer oil flow meter oil flow gauge water flow meter water pressure gauge
EXTRA HEAT EXCHANGER
14 Oil flow l/s M Type designation anufacturer
Valve size mm 15 TRANSMITTERS
on top oTEMPERATURE GAUGES AND
Winding based il Top oil Location reading
hottest winding at the transformer doubled all windings Pt100 transmitters included Pt100 transmitters included
Winding based on bottom me cases) oi e cases) oil (in so Bottom l (in somLocation reading
hottest winding at the transformer doubled all windings Pt100 transmitters included Pt100 transmitters included
Other gauges and transmitters
oil temperature in and out of the forced oil coolers water temperature in and out s of water cooler
Ga urer ation uge / Transmitter Manufact Type designW g indin thermometer To p oil thermometer Bottom oil thermometer Pt100 – winding Pt100 – top oil Pt100 – bottom oil Pt100 – cooling oil (OFWF) Pt100 – cooling water (OFWF)
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16 EXPANSION EM SYSTGeneral
open air system with brane rubber mem separated OLTC system common OLTC system
Con ation servator loc on the transformer on wall brackets on concrete shelf on separate support brackets / support included
Volumes Oil volume in main tank and coolers (radiators) at –40°C m3
Main conservator oil volume m3 Gas and oil actuated relay
with by-pass tube with ins platform pection Manufacturer Type designation
OLTC protective relay Manu Tfacturer ype designation
M diain oil level in cation
at service level on the main conservator Manufacturer Type designat ion
OLTC oil level indication
at service level on the OLTC conservator Manufacturer Type de nsignatio
Dehydrating breathers
maintenance-free non maintenance-free M ype on, main anufacturer, main T designati M Type designation, OLTC anufacturer, OLTC
17 TANK General
welded cover bolted cover
leakage flux shunts on HV side on LV side Cu Al –screen stainless steel inlay in cover in tank wall
Sudden press itor ure monManufacture gnationr Type desi
Surface treatment E Intexternally rnally Corrosivity category C3 C4 C5 Primer paint
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Cover paint Cover paint colour Total thickness µm µm 18 DIMENSIONS & MASSES Dimensions -total dimensions L× H: × × mmW × Masses -total including oil tons -tank tons -transport with oil ton cces tons s -a sories -transport without oil tons -press tons board -active part (core + windings) tons -paper tons -copper tons -press tons board -oil ton tons s 19 SITE INSTAL IO ANLAT N & TR SPORT Installation
in open air w tective walls ithin pro in rock cavity others: -according to drawing No. Erected on
supports wheels s s kid oak planks others: pcs of support s ls in n ths and pc of whee cluded i e supply Rail gauge and support gauge -longitudinal al ly mm ternative -lateral × mm with etw pairs mm c/c b een rail with centrally located support wheel Transport
designed for railw ort on coach No (Green Cargo coach No.)
ay transp Swedish .
designed for road transport -transport dimensions L × W × H: mm × ×
impact recorder i during t nstalled ransport manufacturer sign type de ation
20 WINDING DESIGN & INSULATION SYSTEM Winding design
Paper DP-number Physical winding
Corresponding terminal
Winding type Winding material
0,2% proof stress (N/mm2) new processed
A B C D E F Insulation system
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total barrier thickness % % % total spacer width HV/MV % HV/LV % MV/LV % 21 LOA SES F ER- ANS RSLoading cases for veri and/ or ng o oltag
DING CA OR INT BUS TR FORME fication optimisi f rated v es
Case No. OLTC Pos
Unit WindingI
WindingII
WindingIII
WindingIV
#0 No-load, prin pal tap
U kV ci
U kV P MW
#1 Normal case Q Mvar
U kV P MW
#2 Control case
Q Mvar
U kV P MW
#3 Control case
Q Mvar
U kV P MW
#4 Control case
Q Mvar
U kV P MW
#5 Control case
Q Mvar
U kV P MW
#6 Peak load, emergency operation
Q Mvar
U kV P MW
#7 Temperature rise test (conventional)
Q Mvar
Sign conventions: -Positive power = power into the winding -Negative power = power out of the winding -A reactor is consuming reactive power -A capacitor is producing reactive power
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22 LOADING CASES FOR GENERATOR STEP UP TRANSFORMERS Loading cases for verification and/ or optimising of rated voltages Case No. OLTC - Winding Winding
II Winding III
Winding Unit Pos I IV
#0 No-load, principal U kV tap
U kV P MW
#1 Normal case U1= normal UN Pg=Pgr Q1=0
Q Mvar
U kV P MW
#2 Control case U1=95%UN Pg=P r,
gr Q Mvar g
Q1=1/3×P
U kV P MW
#3 Control case U1=100%UN Pg=Pgr, Q1=1/3×Pgr
Q Mvar
U kV P MW
#4
%UN
gr
Mvar
Control case U1=105Pg=Pgr,Q1=1/4×P
Q
U kV P MW
#5 Control U1=100Pg=Pgr,
case %UN
Q1=+1/6×Pgr
Q Mvar
U kV P MW
#6 Control case Hotspot 98°C, ambient
%Ugr
gr
20°C Ug=100Pg=Pgr,Qg=1/3×P
Q Mvar
U kV P MW
#7 Temperatest (conven
ture rise
tional) Ug=95%Ugr Pg=Pgr, Qg=1/3×Pgr
Q Mvar
Sign conventions: d: Legen-Positive power = power in n etwork to the wi ding - N = n-Negative power = power o ted ut of the winding - r = ra-A reactor is consuming reactive power - g = generator -A capacitor is producing reactive power - 1 = HV winding
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23 AIR CORE INDUCTANCES Inductances in principal position Winding I II III IV Air core inductance
mH/limb
Note: For auto conn as one winding ection the series and common winding in series are considered 24 CAPAC ES Capacitances in principal position - resulting values between terminals and terminal to ground
ITANC
Winding pair I/II I/III II/III -total capacitance nF/limb Winding I II III IV -total capacitance nF/limb Note: For auto connection the series and common winding in series are considered as one winding 25 FAULT URRENTS Three phase faults state currents in kA)
C(steady
Winding / Termina Fault current Faulty terminal
OLTC pos l
Winding Terminal kV kV kV kV kV kV Single phase earth faults (steady state currents in kA) Winding / Terminal Fault current Faulty
terminal X0 / X+ OLTC
pos Winding Terminal kV kV kV kV kV 26 ZERO SEQUENCE IMPEDANCES Zero sequence no-load impedance at rated line current through the neutral point. winding (principal tapping) zero sequence impedance % reference power MVA Zero series winding impedance at rated current in principal tapping windings Measured/short-circuited zero sequence impedance % reference power MVA
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27 INRUSH CURRENTS Max terminal inrush current winding I II III IV peak inrush current
kApeak
half value time s -at rated voltage, in principal tapping and network conditions in accordance with this data compilation -remanence flux density T 28 REQUESTED ALTERNATIVES Requested alternatives according to these guidelines and / or IEC Guideline
Clause IEC 60076-1 Clause
Requested alternative
5.1 - Extended bushing turret 13.5 Impedance protection power supply 15.9 Gas and oil actuated relay inspection platform 19.1.3 Accessory summary plate 19.1.4 Oil circuit diagram 20.2 Winding location diagram 20.2 Voltage stress diagram 20.2 Short circuit stress diagram 22 Design review 23.7.4/23.8.1 Zero sequence impedance measurement 23.8.5 Sound level measurement 10.1.3.b Capacitance measurement 10.1.3.g Measurement of no-load current harmonics 10.1.3.h Measurement of power taken by fans and oil pumps 10.1.3.i Measurements winding insulation resistance and dissipation factor
29 TENDER ENCLOSURES Tender enclosures (X-marked are compulsory as well as the tender references) -item - tender reference No. Factory description Reference list Failure record Test resources Dimension drawing Transport drawing, railway Circuit diagram Winding location diagram Test circuit, impulse tests Test circuit, power frequency tests Recommended priced spare parts List of technical deviations Time schedule Valid type test reports Quality management system Quality management system certificate
Eco management system Eco management system certificate
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Environmental impact for the complete transformer delivery
Surface protection and painting system description
