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CIGRE Study Committes A3CIGRE Study Committes A3 High Voltage EquipmentHigh Voltage Equipment VCB at transmission voltagesVCB at transmission voltages UHV requirementsUHV requirements HVDC switchgearsHVDC switchgears Controlled switchingControlled switching
Hiroki ItoHiroki ItoChairman, CIGRE Study Committee A3Chairman, CIGRE Study Committee A3
AORC-CIGRE meeting, Guangzhou China 3rd-4th September, 2013
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Founded in 1921 as SC 3 studied design and developments on circuit breakers. In 2002 the scope was extended to all substation equipment.The mission of Study Committee A3 is to facilitate and promote the progress of engineering and the international exchange of information and knowledge in the field of high voltage equipment, and to add value to this information and knowledge by means of synthesizing state-of-the-art practices and developing recommendations
What is What is Study Committee A3Study Committee A3
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WG 13.01 Interrupting phenomenaWG 13.01 Interrupting phenomena
Transition from Air Blast Breakers (ABB) to GCB occurred in late 1960s.Higher voltage and larger capacity GCB developments were accelerated in 80’s & 90’s.
Technical breakthrough on HV-VCB is required.Development slowed down in the middle of the 1990’s.
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WG A3.27: Application of vacuum switchgear at WG A3.27: Application of vacuum switchgear at transmission voltagetransmission voltage
72 kV VCB (China)132 kV 16 kA VCB (UK)245 kV load switch (USA)
HV-VCB technical meritsFrequent switching capability, Less maintenance work, SF6 freeHV-VCB challenges at transmission level despite of excellent experience at distributionLimited experience on long term reliabilityScatter of dielectric performance especially for capacitive current switchingLimited current carrying capability, limited unit voltage
145 kV & 72 kV VI (Germany)72 kV 31.5 kA VCB (Japan)72.5 kV 31.5 kA VCB (France)
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T : 200.0 [μs/DIV]U : 50 [kV/DIV]I : 5 [A/DIV]
Current chopping Current chopping behaviourbehaviour of VCBof VCB
CurrentChopping=2.4 A
T :50.0 [μs/DIV]U : 50 [kV/DIV]I : 5 [A/DIV]
Breaking Current Breaking Current IIrmsrms = 200A= 200A
Lg
CsGeT.VCB
V I
T.R Aux.CB
<Test circuit>
Parallel Capacitance
0
1
2
3
4
5
0.0 0.1 1.0Parallel capacitance Cs [μF]
Cho
ppin
g cu
rren
t [A
]
Current chopping of HV-VCB during inductive current switching can be can be reduced to 2reduced to 2--3 A levels with new 3 A levels with new contact materials.contact materials.
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High frequency reiginition of High frequency reiginition of VCBVCB High frequency High frequency reignitionreignition of of GCBGCB
5ms5ms
U : 50 [kV/DIV]I : 500 [A/DIV]
U : 50 [kV/DIV]I : 500 [A/DIV]
HF interruption is not observed.HF interruption => multiple reignition
Model VCB>Test voltage :
72.7kV>Breaking current :
350A>Rated frequency :
50/60Hz
Model GCB>Test voltage :
72.7kV>Breaking current :
350A>Rated frequency :
50/60Hz
00
00
100μs 100μs
U : 50 [kV/DIV]
I : 500 [A/DIV]
U : 50 [kV/DIV]
I : 500 [A/DIV]
OverVoltage(1.2PU)
OverVoltage(1.5PU)
current current
Lord sidevoltage
Lord sidevoltage
current
Lord sidevoltage
High frequency interruption during inductive load switching
1.0PU
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SLF(L90) interruption of SLF(L90) interruption of VCBVCB SLF(L90) interruption of SLF(L90) interruption of GCBGCB
Post arc current after SLF interruption
0
3μs
current
voltageacross CB
I : 5 [A/DIV]U : 5 [kV/DIV]
1.2 A
Post arccurrent
2ms
I : 50 [kA/DIV]U : 5 [kV/DIV] Model GCB
>Rated voltage :420kV
>Breaking current :63kA x 0.9
>Rated frequency :60Hz
0
3μs
current
voltageacross CB
I : 5 [A/DIV]U : 5 [kV/DIV]
6.2A
Post arccurrent
I : 20 [kA/DIV]U : 5 [kV/DIV]
2ms
Model VCB>Rated voltage :
72/84kV>Breaking current :
31.5kA x 0.9>Rated frequency :
50/60Hz
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WG A3.22/28: Requirements for UHV equipmentWG A3.22/28: Requirements for UHV equipment
12.1 14.020.1
25.7
7.6200019901980197019601950 2010 2020
550
800
380kV(1952-,Sweden)
1200kV(1985-91,USSR)
1100kV(2008-,China)
1200kV(2012-,India)
300
Highest voltage of AC power transmission kV
1100kV field tests(1996-,Japan)
year
420kV(1957-,USSR)
787kV(1967-,USSR) 800kV
(USA, South Africa, Brazil, Korea, China)
4.8
735/765kV(1965-,Canada)
World electricity consumption (1000TWh)
11001200
420
A3 provided IEC technical background of UHV specifications for their standardisation worksTB362: Technical requirements for substation equipment exceeding 800 kVTB456: Background of technical specifications for substation equipment exceeding 800 kVWG A3.28 will publish a TB on switching phenomena. WG A3.33 will investigate equipment for series/shunt compensation.
Russia 1200kV GCB Japan 1100kV testing field China 1100kV projects India 1200kV testing field
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Insulation level: LIWV and LIPLInsulation level: LIWV and LIPL
LIWV for 800 kV=(1.34~1.71) x LIPL and LIWV for UHV=(1.25~1.48) x LIPL,providing LIPL with the residual voltage of MOSA at 20 kA. LIWV requirements for UHV transformers in Italy, Russia, India and China are comparable.LIWV requirements for other UHV equipment are fairly close.Japan studies the insulation levels in UHV systems using the EMTP analysis with a lightning current of 200kA-1s/70s 9
China
1100 kV
0
1
2
3
4
IEC 800 kVHydro Quebec
765 kV
2.763.21
FURNAS
800 kV AEP
800 kV Russia
1200 kV
(With MOSA)Ligh
ting
Impu
lse W
ithst
and
Volta
ge (p
.u.)
x1.34
LIPL:2.41
2.993.21
Tran
sfor
mer
Othe
r equ
ipm
ent
x1.47
LIPL:2.18
3.21 3.21
Tran
sfor
mer
Othe
r equ
ipm
ent
x1.34
LIPL:2.41
3.14 3.14
Tran
sfor
mer
Othe
r equ
ipm
ent
x1.44
LIPL:2.17
LIWV = (1.34-1.71) x LIPL for 800 kV, (1.25-1.48) x LIPL for UHV
Japan
1100 kV
2.172.51
Tran
sfor
mer
Othe
r equ
ipm
ent
x1.39
LIPL:1.80
x1.14 x1.20
India
1200 kV
2.30 2.45
Tran
sfor
mer
Othe
r equ
ipm
ent
x1.41
LIPL:1.74
x1.32
2.51 2.67
Tran
sfor
mer
Othe
r equ
ipm
ent
x1.48
LIPL:1.80
x1.39
2.30 2.45
Tran
sfor
mer
Othe
r equ
ipm
ent
LIPL:1.80
x1.36x1.28
Italy
1050 kV
2.62 2.62
Tran
sfor
mer
Othe
r equ
ipm
ent
x1.25
LIPL:2.10
x1.37
KEPCO
800 kV
3.14 3.44
Tran
sfor
mer
Othe
r equ
ipm
ent
x1.71
LIPL:2.01
Tran
sfor
mer
Othe
r equ
ipm
ent
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Insulation level: SIWV and SIPL
SIWV for 800 kV=(1.18~1.42) x SIPL and SIWV for UHV=(1.08~1.23) x SIPL, providing SIPL with the residual voltage of MOSA at 2 kA. SIWV requirements for 1200 kV in Russia and India have the same values.SIWV requirements for 1100 kV in China and Japan are slightly different.The applications of new technologies such as MOSA with higher performance, CB with opening/closing resistors, DS with switching resistor can effectively suppress the switching surges, which is a predominant factor to reduce the construction cost of UHV transmission. 10
0
1
2
3
4
IEC 800 kVHydro Quebec
765 kV
1.992.18
FURNAS
800 kV AEP
800 kVSwitc
hing
Impu
lse W
ithst
and
Volta
ge (p
.u.)
x1.18
SIPL:1.85
2.37 2.18
Tran
sfor
mer
Othe
r equ
ipm
ent
x1.25
SIPL:1.75
2.37 2.37
Tran
sfor
mer
Othe
r equ
ipm
ent
x1.28
SIPL:1.85
2.60 2.60
Tran
sfor
mer
Othe
r equ
ipm
ent
x1.42
SIPL:1.83
SIWV = (1.18-1.42) x SIPL for 800 kV, (1.08-1.23) x SIPL for UHV
x1.07 x1.36
Russia
1200 kV
(With MOSA)
1.84 1.84
Tran
sfor
mer
Othe
r equ
ipm
entSIPL:1.60
x1.15
Italy
1050 kV
2.10 1.95
Tran
sfor
mer
Othe
r equ
ipm
entSIPL:1.69
x1.16
x1.24
India
1200 kV
1.84 1.84
Tran
sfor
mer
Othe
r equ
ipm
entSIPL:1.53
x1.20 x1.23
China
1100 kV
2.00 2.00
Tran
sfor
mer
Othe
r equ
ipm
entSIPL:1.63
Japan
1100 kV
1.59 1.73
Tran
sfor
mer
Othe
r equ
ipm
ent(SIPL:1.60)
x1.08
KEPCO
800 kV
2.30 2.18
Tran
sfor
mer
Othe
r equ
ipm
ent
x1.18
SIPL:1.84
x1.25
Tran
sfor
mer
Othe
r equ
ipm
ent
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Future multi-terminal HVDC LinksJ.HAFNER(ABB),et.al,” Proactive Hybrid HVDC Breakers - A key innovation for reliable HVDC grids ”,CIGRE Bologna-264 2011
LCC HVDC ±800 kV dc put in service up to 8GW±1000 kV dc being developed in China
VSC HVDC ±320kV dc operated up to 800MWStrong need for connection of offshore wind farms
SC B4 investigationsWG B4.52: HVDC Grid Feasibility Study, TB533 WG B4.56: Guidelines for the preparation of connection agreements for HVDC grids WG B4.57: Guide for the development of models for HVDC converters in a HVDC grid WG B4.58: Methodologies for direct voltage control in a meshed HVDC Grid WG B4/B5.59: Control and Protection of HVDC Grids JWG A3/B4.34 on DC switchgear
Achievements & main strategic directions ofAchievements & main strategic directions of SC B4: HVDC & Power ElectronicsSC B4: HVDC & Power Electronics
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DCCB Mechanical Semiconductor Hybrid type
Interrupting components
GCBVCB
IGBT(Full Bridge VSC)
IGBTHigh speed DS
Loss Negligible Large Small
Fault clearing time 50-100 ms 0.2 ms 5 ms
Development items
FCLHigh speed switching
Cost reductionReliability
Cost reductionHigh speed DS
Cost Economical Expensive Expensive
Configuration
Circuit Breaker
MO Varistor
Capacitor Reactor
Semiconductor switching element
MO Varistor
High speed switch
DCCB different interrupting typestypes
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The method is applied to several 100 V class DC-NFB & air-insulated high speed switch used for railway system.The prolonged arc generated voltage across the circuit breaker contacts limits the DC current.
Current limiting method Forced current commutation Self current commutation
I Va
MOSA
Circuit Breaker
I
Va t
Arc voltage
Application of the method is limited since large capacity capacitor bank is required.
The pre-charged capacitor imposes an oscillating current on the DC current and creates the current zero.
The method is applied to MRTB which interrupt the DC current in the neutral line of 250kV HVDC transmission.The parallel capacitor and reactor across the circuit breaker generates the current oscillation, which eventually leads to the current zero.
Conventional mechanical DCCB
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DC equipment required for HVDCDC equipment required for HVDCDC equipment applied to HVDC grid would be important A3 subjects for the next decade. JWG A3/B4.34 will investigate technical requirements on DC switchgear, keeping good relations with B4.
Future tasks could be Requirements of DC equipment for different purposes DCCB development, field demonstration Disconnecting switch & Making switch, technical requirements Earthing switch, HSGS, technical requirements MOSA, MO Varistor, applications for DC transmission FCL requirements for future DC grid DC-gas insulated switchgear (GIS) Testing requirements for all DC equipment
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WG A3.07:WG A3.07: Controlled switchingControlled switching
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Transient Inrush Current at energization depends on the switching angle and the residual flux of the core. The higher residual flux causes the core saturation resulting in larger inrush current.
Controlled transformer switchingControlled transformer switching
Magn
etizi
ng cu
rrent
Symmetrical Flux
Voltage
Current
Flux
Inru
sh cu
rrent
Asymmetrical Flux
VoltageCurrent
Flux
Residual Flux
Random energizationControlled snergization
Inrush current: 1120AVoltage disturbance: 15 %
Inrush current: <100 AVoltage disturbance: <1 %
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Scope & Investigations in Study Committee A3Scope & Investigations in Study Committee A3
Design and development of substation equipmentNew and improved testing techniques Maintenance, Refurbishment and Lifetime management Reliability assessment and Condition monitoring Requirements presented by changing networks, standardizations
A3 Scope
WG investigationsWG A3.06: Reliability of High Voltage EquipmentWG A3.25: MO Surge Arresters for emerging system conditionsWG A3.26: Influence of shunt capacitor banks on circuit breaker fault interruption dutiesWG A3.27: Impact of the application of vacuum switchgear at transmission voltagesWG A3.28: Switching phenomena and testing requirements for UHV & EHV equipmentWG A3.29: Deterioration and ageing of substation equipmentWG A3.30: Overstressing of substation equipmentWG A3.31: Accuracy, Calibration & Interfacing of Instrument Transformers with Digital OutputsJWG A3.32/CIRED: Non-intrusive methods for condition assessment of T&D switchgearsWG A3.33: Experience with equipment for series / shunt compensationJWG A3/B4.34: DC switchgearWG A3.35: Commissioning practices of controlled switching projects
