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Bowthorpe LV/MV Surge Arresters Energy Division
Bowthorpe LV/MV Surge Arresters
Energy Division
2
Bowthorpe pioneered the develop-ment of polymeric housed surge arresters in the early 1980's and since1986 have a proven service experienceacross the globe, operating in theworlds toughest environments.
Bowthorpe “OCP” silicone surge arresters have been designed andtested to meet our customers toughest environmental conditionsand to meet the requirements ofIEC60099-4. Our gapless zinc oxidepolymeric arresters have been in service since 1994 and now the OCP ranges builds on this experienceand know how.
OCP is the latest gapless, zinc oxidearrester family from Bowthorpe. The OCP development was based on 25 years of internal experience in arrester design and manufacture within the Tyco Electronics EnergyDivision. The final “OCP” qualificationwas performed in independent laboratory facilities in Europe. OCP cores are manufactured using superior ZnO varistors, which displayexcellent thermal and current handlingcharacteristics due to the guaranteedhomogeneity of the varistor volume.This superior thermal behavior yieldsproducts with:
• Excellent TOV performance.• Safe, non-shattering failure in the
short circuit test by pre-failing tohigher fault currents.
• High energy handling capability.
TVC DLA1 OCP2
Uc 4.8kV 3-29kV 3-41kV
IN 5kA 10kA 10kA
Long duration energy (2 shots / kJ/kV Uc) N/A 2.9 kJ/kV Uc 6.0 kJ/kV Uc
Long duration waveform 250A / 2ms 250A / 2ms 530A / 2ms
10 second TOV, (UTOV / Uc) 1.5 1.43 1.35
High current short circuit 16kA 25kA 40kA
Core technology TVC OCP OCP
Please contact your local sales representative for higher Uc arresters.
Bowthorpe DLA/OCP benefits:
Tested in accordance withIEC60099-4 at independent accredited laboratories
Superior protection margins
Direct molded housing to preventmoisture ingress
Low residual voltages
High-energy handling
Superior TOV performance
Safe non-shattering short circuitbehavior to higher current levels
Maintenance free
Hydrophobic silicone housing: (Tracking and erosion resistant)
Excellent cantilever and tensile performance
Excellent mechanical, vibration andimpact withstand capability
Quality design and manu facturing,ISO 9001 and 14001 compliant
TRUST Bowthorpe Surge Arresters
Bowthorpe EMP LV/MV surge arresters OCP, Open Cage Polymeric series
3
Excellent hydrophobicity Safe short circuit failure Superior TERT performance
At the core of the Bowthorpe OCPdesign is our improved ZnO varistordisk, which has superior thermal andelectrical characteristics and stability.The resulting new varistor and OCPdesign combination has resulted insuperior energy handling and TOVperformance.
The construction of the OCP designcomprises of:1 ZnO, (Zinc Oxide) varistors2 Bowthorpe proprietary silicone
housing3 Flame retardant FRP structure4 Corrosion resistant aluminium
fittings
The crimped structural constructionensures light weight product withoptimal mechanical strength. The manufacturing process ensuresvoid free construction and optimuminterface sealing. This is achieved bybonding the silicone housing directlyto the ZnO discs and aluminium fittings using a Bowthorpe proprietarybonding solution.
The silicone housing was developedusing the knowledge accumulatedover 35 years of internal materials science expertise and experience,resulting in an optimum shed profileand a material with excellent trackingand erosion resistance.
Features of our new hydrophobic silicone OCP design are:• Alternating sheds for superior
pollution flash over resistance• Superior TERT performance• Constant voltage: 4.5kV, >360min
- Stepped voltage: >300min- All eventual failures by erosion
only, ie no tracking in step voltage test
• Housing tested to IEC 1000hr salt fog test
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2
3
4
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Bowthorpe EMP, TVC Transient Voltage Clampers
Principle of OperationTVCs incorporate a gapless metaloxide varistor, MOV design that understeady state conditions maintains theline-to-ground voltage across theTVCs terminals. When overvoltagesoccur, the TVC conducts current toearth, limiting the overvoltage tobelow the required protection levels.Upon passage of the overvoltage con-dition, the TVC returns to a highlynon-linear steady state condition thatconducts very minimal 10’s of Hzpower current.
M 12 Stainless
Steel Termination
Zinc Oxide
Varistor Core
UV Stable
Tracking Resistant
Housing
Current-voltage characterisitc for Zno varistor
Current (Amps/mm2)
20°C
60°C
Continuous operating voltage
Protection against Switching over-voltages
Rated voltage
Protection against Lightning over-voltages
Pre-break-
down
region
Breakdown region High current
region
120°C
Vo
ltag
e (
V/m
m)
Background – ConstructionTransient Voltage Clampers aredesigned under the same principleas LV voltage surge arresters; how-ever applications are more specific.
IntroductionIn the UK where severe lightning isoften accompanied by poor poleearthing resistance, the secondary LV distribution system is subjected tohigh voltage surges due to lightningcurrent seeking alternate groundpaths through the low-voltage circuits.The typical mode of failure of a polemounted transformer is for the lowvoltage winding to flash over to thetransformer tank due to the relativelyhigh voltage developed across thepole earth resistance. The high voltagearrester does not prevent this type offailure. However, to remove this sourceof failure (or back flash over) a TVCmay be placed between the neutralbushing and the tank.
What is a Transient Voltage Clamper,TVC?A TVC is used to protect against theinternal failure of a pole mountedtransformer (PMT) due to “backflashover” between the transformertank and the LV winding bushing. A “back flashover” on a PMT willcause permanent damage to thetransformer internal solid insulation.
Conditions of Use?1) TVC’s are useful when there is veryhigh resistivity pole grounding condi-tions e.g. hot, sandy, rocky ground.Under these soil conditions an earthresistance of 10 ohms or less may bedifficult to achieve; resistance maybevariable throughout the year.2) TVC’s are useful when the LV earth“downstream” from the PMT is lowerthan at the pole earth resistance. 3) Best used in conjunction with HVand LV surge arresters (cannot beused instead).
Application Diagram
Lightning Strike - 5 kA
Surge Arrester on HV side
HV Winding
LV Winding
Neutral Bushing
10 Ohms
Ground at Pole Mounted
Transformer
Tank of Transformer
Ground at Consumer Premises
Single / 3 PhaseDistribution Line
TVC-1
5
Bowthorpe EMP, TVC Transient Voltage Clampers
Example Problem: A moderate light-ning current of 5kA flowing to earthinto a resistance of 10 ohms will raisethe tank of the transformer to 50kVas V = IR. Typically the impulse break-down voltage of the LV winding to thetransformer case is 30kV. The tankvoltage due to 10 ohms earth resist-ance can cause a breakdown betweenthe tank and a low voltage bushing ofthe transformer. Any back flashoverwill drive high current through the lowvoltage windings when striking thephase connections. These high currentsare driven by the power frequency flowcurrent.
Solution: To remove the back flashovera suitable device must be connectedbetween the neutral bushing and thetank of the transformer, hence a TVCshould be installed. In order to becompatible with standard auto recloseroperations in the event of a fault, thedevice must be able to withstand thephase to earth voltage for at least 10 seconds.LV and HV surge arresters cannot beused instead of a TVC. LV Surge arresters: The LV arrestershould be used in lightning proneexposed areas to give additional protection. They should be installedon the low voltage system, on the first pole down stream from the transformer.
HV Surge arresters: The HV arrestershould be fitted to the high voltagebushings (connections under 300mmin length to limit voltage drop). Theinstallation of the HV arrester preventsdamage to the insulation on the HVwinding and the transformer case. Note: The HV arrester will not stopback flashovers across the low voltagebushings, but will limit the power follow-current, hence this is the reasonwhy TVC’s should be used.Tips: To reduce the voltage on the tankof the transformer, it is advisable tohave low values of earthing resistanceconnected to the tank, approximately5 ohms or less. To achieve an optimumovervoltage protection, connectingleads should be as short as possible.
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Bowthorpe EMP Distribution Lightning Arresters
Application:
Protection of MV networks and equipment from lightning and switching surgerelated over-voltages in areas with relatively high iso-keraunic levels. Suitablefor both outdoor and indoor use to protect transformers and cable end terminations.
Generic technical data:
DLA1 series 3-29kV Uc
Rated discharge current (8/20µs): 10kA
Line discharge class 1 according to IEC 60099-4
Long duration current impulse (2000µs): 250A
High current short circuit: (pre-failing method) 25kA(Safe non-shattering failure mode)
Energy 2 Long duration impulses: 2.9kJ/kVUc
Temperature of samples (pre-heated): 60º C according to IEC 60099-4, Ed 2.0 2004. TOV Curve applies to an arrester which has a pre-stress applied prior to TOV verification. This pre-stress is equivalent to one high current impulse as per the operating duty test.
Uw = TOV withstand voltage; Uc = continuous operating voltage
Time (s)
1
1.55
1.50
1.45
1.40
1.35
1.30
1.2510000100010010
Uw
/ U
c
TOV Curve
TOV of DLA1 with single shot high current prior energy
Bowthorpe DLA1 benefits:
Tested in accordance withIEC60099-4 at independent accredited laboratories
Superior protection margins
Direct molded housing to preventmoisture ingress
Low residual voltages
High-energy handling
Superior TOV performance
Safe non-shattering short circuitbehavior to higher current levels
Maintenance free
Hydrophobic silicone housing: (Tracking and erosion resistant)
Excellent cantilever and tensile performance
Excellent mechanical, vibration andimpact withstand capability
Quality design and manu facturing,ISO 9001 and 14001 compliant
TRUST Bowthorpe Surge Arresters
DLA1 series
7
L
97mm
119mm
Notes:
Mechnical strength data:
Cantilever Nm 250
Tensile kN 2
Torque Nm 50
For accessory and ordering informa-tion, please refer to page 11
Tested in accordance with IEC 60099-4, Ed 2.0 2004
DLA1 U continuous U rated U residual in kV when tested to the following impulse waveformskV(r.m.s) kV(r.m.s) Lightning (8/20µs) Steep lightning (1/20µs) Switching (30/60µs)
5kA 10kA 20kA 10kA 125A 500A
3 3 3.7 9.80 10.50 11.89 11.49 7.63 7.97
4 4 5.0 13.07 14.00 15.85 15.32 10.17 10.62
5 5 6.2 16.34 17.50 19.81 19.15 12.71 13.28
6 6 7.5 19.61 21.00 23.77 22.98 15.25 15.94
8 8 10.0 26.14 28.00 31.70 30.64 20.34 21.25
9 9 11.2 29.41 31.50 35.66 34.47 22.88 23.90
10 10 12.5 32.68 35.00 39.62 38.30 25.42 26.56
12 12 15.0 39.22 42.00 47.54 45.96 30.50 31.87
15 15 18.7 49.02 52.50 59.43 57.45 38.13 39.84
18 18 22.5 58.82 63.00 71.32 68.94 45.76 47.81
20 20 25.0 65.36 70.00 79.24 76.60 50.84 53.12
21 21 26.2 68.63 73.50 83.20 80.43 53.38 55.78
22 22 27.5 71.90 77.00 87.16 84.26 55.92 58.43
24 24 30.0 78.43 84.00 95.09 91.92 61.01 63.74
29 29 36.0 94.80 101.50 114.90 111.10 73.70 77.00
DLA1-xxS; Standard housing parameters
DLA1 Impulse Power frequency Flash Creepage Heightvoltage voltage withstand, over L1.2/50µs wet distance (kV) (kV) (mm) (mm) (mm)
3 106 47 176 379 183
4 106 47 176 379 183
5 106 47 176 379 183
6 106 47 176 379 183
8 106 47 176 379 183
9 106 47 176 379 183
10 106 47 176 379 183
12 106 47 176 379 183
15 128 57 214 503 220
18 154 68 254 629 260
20 154 68 254 629 260
21 180 80 293 755 299
22 180 80 293 755 299
24 180 80 293 755 299
29 205 91 334 882 334
DLA1-xxL; Extended housing parameters
DLA1 Impulse Power frequency Flash Creepage Heightvoltage voltage over L1.2/50µs withstand, wet distance (kV) (kV) (mm) (mm) (mm)
3 128 57 214 503 214
4 128 57 214 503 214
5 128 57 214 503 214
6 128 57 214 503 214
8 128 57 214 503 214
9 128 57 214 503 214
10 128 57 214 503 214
12 128 57 214 503 214
15 154 68 254 629 254
18 180 80 293 755 293
20 180 80 293 755 293
21 205 91 334 882 334
22 205 91 334 882 334
24 205 91 334 882 334
Bowthorpe EMP Distribution Lightning Arresters DLA1 series
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Application:
Protection of MV networks, sensitive equipment and substations from lightningand switching surge related over-voltages in areas with relatively high iso-keraunic levels.
Generic technical data:
OCP2 series 3-41kV Uc
Rated discharge current (8/20µs): 10kA
Line discharge class 2 according to IEC 60099-4
Long duration current impulse (2000µs): 530A
High current short circuit: (pre-failing method) 40kA(Safe non-shattering failure mode)
Energy 2 Long duration impulses: 6.0kJ/kVUc
Temperature of samples (pre-heated): 60° C according to IEC 60099-4, Ed 2.0 2004. TOV Curve applies to an arrester which has a pre-stress applied prior to TOV verification. This pre-stress is equivalent to two long duration currentimpulses having duration of 2000µs and total energy equal to 6.0 kJ/kV Uc.
Uw = TOV withstand voltage; Uc = continuous operating voltage
Time (s)
1
1.6
1.5
1.4
1.3
1.2
1.1
1.010000100010010
Uw
/ U
c
TOV Curve
TOV for OCP2 with prior energy
Bowthorpe EMP OCP benefits:
Tested in accordance withIEC60099-4 at independent accredited laboratories
Superior protection margins
Direct molded housing to preventmoisture ingress
Low residual voltages
High-energy handling
Superior TOV performance
Safe non-shattering short circuitbehavior to higher current levels
Maintenance free
Hydrophobic silicone housing: (Tracking and erosion resistant)
Excellent cantilever and tensile performance
Excellent mechanical, vibration andimpact withstand capability
Quality design and manu facturing,ISO 9001 and 14001 compliant
TRUST Bowthorpe Surge Arresters
Bowthorpe EMP Open Cage Polymeric arresters OCP2 series
100000
9
OCP2 U continuous U rated U residual in kV when tested to the following impulse waveformskV(r.m.s) kV(r.m.s) Lightning (8/20µs) Steep lightning (1/20µs) Switching (30/60µs)
5kA 10kA 20kA 10kA 125A 500A
3 3 3.7 9.18 9.72 10.84 10.10 7.37 7.76
4 4 5.0 12.24 12.96 14.46 13.47 9.83 10.35
5 5 6.2 15.30 16.20 18.07 16.84 12.29 12.94
6 6 7.5 18.36 19.44 21.68 20.21 14.75 15.53
8 8 10.0 24.48 25.92 28.91 26.94 19.66 20.70
9 9 11.2 27.54 29.16 32.53 30.31 22.12 23.29
10 10 12.5 30.60 32.40 36.14 33.68 24.58 25.88
12 12 15.0 36.72 38.88 43.37 40.42 29.50 31.06
15 15 18.7 45.90 48.60 54.21 50.52 36.87 38.82
18 18 22.5 55.08 58.32 65.05 60.62 44.24 46.58
20 20 25.0 61.20 64.80 72.28 67.36 49.16 51.76
21 21 26.2 64.26 68.04 75.89 70.73 51.62 54.35
22 22 27.5 67.32 71.28 79.51 74.10 54.08 56.94
24 24 30.0 73.44 77.76 86.74 80.83 58.99 62.11
29 29 36.3 88.74 93.96 104.81 97.67 71.28 75.05
Notes:
Mechnical strength data:
Cantilever Nm 350
Tensile kN 2
Torque Nm 50
For accessory and ordering informa-tion, please refer to page 11
L
97mm
119mm
Tested in accordance with IEC 60099-4, Ed 2.0 2004
OCP2-xxS; Standard housing parameters
OCP2 Impulse Power frequency Flash Creepage Heightvoltage voltage withstand, over L1.2/50µs wet distance (kV) (kV) (mm) (mm) (mm)
3 145 47 176 380 183
4 145 47 176 380 183
5 145 47 176 380 183
6 145 47 176 380 183
8 145 47 176 380 183
9 145 47 176 380 183
10 145 47 176 380 183
12 145 47 176 380 183
15 165 57 214 505 220
18 180 70 254 632 260
20 180 70 254 632 260
21 200 80 293 758 299
22 200 80 293 758 299
24 200 80 293 758 299
29 230 95 334 885 340
OCP2-xxL; Extended housing parameters
OCP2 Impulse Power frequency Flash Creepage Heightvoltage voltage withstand, over L1.2/50µs wet distance (kV) (kV) (mm) (mm) (mm)
3 165 57 214 505 220
4 165 57 214 505 220
5 165 57 214 505 220
6 165 57 214 505 220
8 165 57 214 505 220
9 165 57 214 505 220
10 165 57 214 505 220
12 165 57 214 505 220
15 180 70 254 632 260
18 200 80 293 758 299
20 200 80 293 758 299
21 230 95 334 885 340
22 230 95 334 885 340
24 230 95 334 885 340
Bowthorpe EMP Open Cage Polymeric arresters OCP2 series
OCP2 U continuous U rated U residual in kV when tested to the following impulse waveformskV(r.m.s) kV(r.m.s) Lightning (8/20µs) Steep lightning (1/20µs) Switching (30/60µs)
5kA 10kA 20kA 10kA 125A 500A
29 29 36.3 88.74 93.96 104.81 97.67 71.28 75.05
30 30 37.5 91.80 97.20 108.42 101.04 73.74 77.64
31 31 38.8 94.86 100.44 112.03 104.41 76.20 80.23
33 33 41.3 100.98 106.92 119.26 111.14 81.11 85.40
36 36 45.0 110.16 116.64 130.10 121.25 88.49 93.17
39 39 48.8 119.34 126.36 140.95 131.35 95.86 100.93
40 40 50.0 122.40 129.60 144.56 134.72 98.32 103.52
41 41 51.3 125.46 132.84 148.17 138.09 100.78 106.11
10
Notes:
Mechnical strength data:
Cantilever Nm 350
Tensile kN 2
Torque Nm 50
For accessory and ordering informa-tion, please refer to page 11
L
107mm
137mm
Tested in accordance with IEC 60099-4, Ed 2.0 2004
OCP2-xxM; Standard housing parameters
OCP2 Impulse Power frequency Flash Creepage Heightvoltage voltage withstand, over L1.2/50µs wet distance (kV) (kV) (mm) (mm) (mm)
29 204 98 339 970 343
30 204 98 339 970 343
31 228 110 378 1125 383
33 228 110 378 1125 383
36 250 122 418 1279 423
39 250 122 418 1279 423
40 250 122 418 1279 423
41 250 122 418 1279 423
OCP2-xxML; Extended housing parameters
OCP2 Impulse Power frequency Flash Creepage Heightvoltage voltage withstand, over L1.2/50µs wet distance (kV) (kV) (mm) (mm) (mm)
29 228 110 378 1125 383
30 228 110 378 1125 383
33 250 122 418 1279 423
36 250 122 418 1279 423
Bowthorpe EMP Open Cage Polymeric arresters OCP2 series
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Arrester type:
DLA1 = 10kA, class 1 (3-29 kV)
OCP2 = 10kA, class 2 (3-41 kV)
Uc (kV) 3-29 30-41
Standard creepage S M
Extended creepage L* ML**
* available up to Uc = 24 kV
**available up to Uc = 36 kV
Accessory selection
M = Mounting bracket
E = Earth connection
L = Line connection
OCP2 and DLA1 series naming and order query description:
Example: OCP = “Open Cage Polymeric”
OCP2 – 12S – MEL
Bowthorpe EMP OCP2 and DLA1 accessories
Line lead accessories
Arrester Type = Continuous Operating Voltage Uc in kV
All accessories use M12 stainless steel studs
Mounting accessories
Ground lead accessories
03 04 05 06 08 09
10 12 15 18 20 21
22 24 29 30 31 33
36 39 40 410 – 12
A B
D M NF
F M N Q V
55mm
V
55mm 55mm
C T
For installation clearances phase-phase (a)
and phase-ground (b) please refer to IEC 60071-2.
b a a
Additional accessory options available on request. Please contact: [email protected] with your specific requirement.
55mm
N
55mm
DLA1 –OCP2 –
55mm
55mm
Thank you for reading this data sheet.
For pricing or for further information, please contact us at our UK Office, using the details below.
UK OfficeKeison Products,
P.O. Box 2124, Chelmsford, Essex, CM1 3UP, England.Tel: +44 (0)330 088 0560Fax: +44 (0)1245 808399
Email: [email protected]
Please note - Product designs and specifications are subject to change without notice. The user is responsible for determining the suitability of this product.
