Surge Arresters Application and Selection - IEEE

1 Surge ArrestersApplication and SelectionAdria JonesPage 2 May 2012 2009 Siemens Energy, Inc. All rights reserved Mounted in parallel to the transformer/equipment Handle over voltage Surge , clamp it down Absorb energy from the Surge Discharge the Surge current to the ground Protect the transformer / equipment Dissipate the energy and remain thermally stable Provide reliable & predictable service, safe performance Mounted in parallel to the transformer/equipment Handle over voltage Surge , clamp it down Absorb energy from the Surge Discharge the Surge current to the ground Protect the transformer / equipment Dissipate the energy and remain thermally stable Provide reliable & predictable service, safe performanceFunctions of Surge ArrestersPage 3 May 2012 2009 Siemens Energy, Inc.

2 All rights reservedSources of Surges Lightning Switching System generated TOV Lightning Switching System generated TOVPage 4 May 2012 2009 Siemens Energy, Inc. All rights reservedFundamentals of Insulation CoordinationTime duration of (over-)voltagePossible voltages without arrestersVoltages limited by arrestersWithstand voltage of equipmentMagnitude of (over.)voltage / overvoltages(Microseconds)Switching overvoltages(Milliseconds)Temporary overvoltages(Seconds)Highest system voltage (Continuously)Page 5 May 2012 2009 Siemens Energy, Inc. All rights reserved SiC + Porcelain ( thru 1978 ) MOV + Porcelain ( 1978 thru 1986 ) MOV + Polymer ( 1986 thru now ) SiC + Porcelain ( thru 1978 ) MOV + Porcelain ( 1978 thru 1986 ) MOV + Polymer ( 1986 thru now )Design TransformationsPage 6 May 2012 2009 Siemens Energy, Inc.

3 All rights reserved MOV Vs SiC Porc Vs SR SR Vs EPDM MOV Vs SiC Porc Vs SR SR Vs EPDMI nternal Elements and HousingPage 7 May 2012 2009 Siemens Energy, Inc. All rights reservedSilicone Carbide Gapped arrester SiC blocks in Porcelain housing with gap structure Design prior to mid 70s Had serious problems of -Moisture Ingress-Unstable Protective Levels-Violent FailuresPage 8 May 2012 2009 Siemens Energy, Inc. All rights reservedSiCZnO10 kASiC50 AVOLTAGECURRENT100 500 AmpsDischarge Voltage1 10 kA< 1 mAIR IR MCOVPage 9 May 2012 2009 Siemens Energy, Inc. All rights reservedSilicone Housed Surge Arresters - Effect of HydrophobicityPage 10 May 2012 2009 Siemens Energy, Inc. All rights reservedDifferent Polymers: Silicone vs. EPDMH ighly Hydrophobic(water-repellent) UV-resistant the best pollution & long-term stabilityHighly Hydrophobic(water-repellent) UV-resistant the best pollution & long-term stability Non-hydrophobic Low UV Rating poor pollution and long-term stability Non-hydrophobic Low UV Rating poor pollution and long-term stabilitySilicone (+++)Refer to Dow Corning R & D PaperEPDM ( - - -)Page 11 May 2012 2009 Siemens Energy, Inc.

4 All rights reserved Test data Compare SR against EPDM and PORCELAIN Recommends SR as the best insulation for Power Systems applications Most utilities prefer SR for housings and insulatorsPage 12 May 2012 2009 Siemens Energy, Inc. All rights reserved Station Class Intermediate Class Distribution Class ( HD, ND, RP ) Transmission Line Arresters ( TLA ) Station Class Intermediate Class Distribution Class ( HD, ND, RP ) Transmission Line Arresters ( TLA )Types of Surge ArrestersPage 13 May 2012 2009 Siemens Energy, Inc. All rights reservedPage 14 May 2012 2009 Siemens Energy, Inc. All rights reservedPage 15 May 2012 2009 Siemens Energy, Inc. All rights reservedSurge Arresters ClassificationPerformance Requirements ( Table of Annex B from IEEE Std )Page 16 May 2012 2009 Siemens Energy, Inc.

5 All rights reserved Protection ( IR, TOV, Energy ) Durability ( MOV blocks, Construction, Mechanical strength, Creepage distance, PD level ) Safety ( Non-fragmenting design, Moisture proof ) Protection ( IR, TOV, Energy ) Durability ( MOV blocks, Construction, Mechanical strength, Creepage distance, PD level ) Safety ( Non-fragmenting design, Moisture proof )Key Features for arrester SelectionPage 17 May 2012 2009 Siemens Energy, Inc. All rights reserved Gapless MOV Poly Wrapped with Grease or Dry interface Poly Cage Directly molded Poly Tube Directly molded Metal Enclosed (GIS) Gapless MOV Poly Wrapped with Grease or Dry interface Poly Cage Directly molded Poly Tube Directly molded Metal Enclosed (GIS)Current DesignsPage 18 May 2012 2009 Siemens Energy, Inc.

6 All rights reservedPorcelain Housed Surge Arresters for High Voltage Pressure relief diaphragmMaterial: Stainless steelPressure relief ventMaterial: AluminiumSupport for MO columnMaterial: FRP rodsPorcelain housingAluminium flangeO-ring sealMO columnSulphur cement bonding(non-porous)Fixing plate (FRP)Bolt terminal (flat terminal available)Housing filled with nitrogento avoid oxygen (causing moisture) in 4 in 3 in in in in 2 inPage 19 May 2012 2009 Siemens Energy, Inc. All rights reservedSilicone Housed Surge Arresters for High VoltageHigh Strength Cage Design, Directly MoldedColumn of MO resistorstotally surrounded by silicone rubber (SR)Silicone rubber housingMaterial: LSRdirectly molded onto theactive partCage of 8 FRP rodsas reinforcement structurePage 20 May 2012 2009 Siemens Energy, Inc.

7 All rights reservedPolymer Housed Surge Arresters for High Voltage- Wrapped Design with Grease Interface EPDM housing in multiple units Not directly moulded No mechanical member inside Deflects under load -- potential for moisture ingressPage 21 May 2012 2009 Siemens Energy, Inc. All rights reservedCantilever Strength ( inch -lbs) MFR - 1 MFR - 2 MFR - 3 Directly Molded SRWrapped ( *)EPDMD irectly MoldedSRWORKING24,78210,000 3,00022,125 7,000 ULTIMATE35,40020,000 5,00035,400 11,500 ( * )JOINTS BETWEEN THE RUBBERS POOR MECHANICALS -- HIGH DEFLECTION Ploymer Housed Surge Arresters for High VoltageCantilever Strength ComparedPage 22 May 2012 2009 Siemens Energy, Inc. All rights reservedSilicone Housed Surge Arresters for High Voltage Extra High Strength Tube DesignMO columnPressure relief ventMaterial: AluminiumPressure relief diaphragmMaterial: Stainless steelSilicone rubber shedsMaterial: SRdirectly molded onto FRP tubeFRP tube for extra high mechanical strengthSupport for MO columnMaterial: FRP rodsHousing filled with nitrogento avoid oxygen Page 23 May 2012 2009 Siemens Energy, Inc.

8 All rights reservedCantilever Strength ( inch - lbs) MFR - 1 MFR - 2 MFR - 3 Tube DesignSRHollow CoreSRTube DesignSRWORKING446,00035,000168,000 ULTIMATE637,00070, 800240,000 Silicone Housed Surge Arresters for High VoltageComparison of Cantilever Strength ComparedTypical porcelain Arresters :Ultimate 150,000 in-lbfWorking 60,000 in-lbfTypical porcelain Arresters :Ultimate 150,000 in-lbfWorking 60,000 in-lbfPage 24 May 2012 2009 Siemens Energy, Inc. All rights reservedDirectly Molded SR Housed Surge Arresters for Distribution Systems(Completely sealed, one piece construction)Silicone Rubber sheds directly molded on active partGlass coating on MOV blockMetal oxide varistor (MOV)Cage of FRP Rodssurrounding MOV columnAluminium end fittingstainless steel studstainless steel studAluminium end fittingHorizontal cross sectionalview of Surge arresterPage 25 May 2012 2009 Siemens Energy, Inc.

9 All rights reserved Gapped SR housed Surge Arresterfor Distribution SystemsPage 26 May 2012 2009 Siemens Energy, Inc. All rights reservedWrapped Design, EPDM HousedSurge arrester for Distribution SystemsCover plate with greaseScrew used for sealing with Top Cap platePre-manufactured EPDM-housing pushed over the wrapped core impregnated with greaseFibre-glass wrapped around MOV resistor column Page 27 May 2012 2009 Siemens Energy, Inc. All rights reservedArrester Terms and Definitions MOV MCOV Duty Cycle voltage Discharge Voltage BIL Protective Margin TOV MOV MCOV Duty Cycle voltage Discharge Voltage BIL Protective Margin TOV Short circuit / Pressure relief rating Creepage distance Cantilever Strength Grading Ring Corona Ring Short circuit / Pressure relief rating Creepage distance Cantilever Strength Grading Ring Corona RingPage 28 May 2012 2009 Siemens Energy, Inc.

10 All rights reservedArresters Ratings Duty Cycle and MCOV ( Table 1. of IEEE Std )Page 29 May 2012 2009 Siemens Energy, Inc. All rights reservedSurge arrester s Application DataRefer to Manufacturers CatalogPage 30 May 2012 2009 Siemens Energy, Inc. All rights reservedPage 31 May 2012 2009 Siemens Energy, Inc. All rights reservedRecommeded Installation Points generally at transitions overhead line - cable generally at the entrance of overhead lines into a station usually in the HV-bushing area of transformers additionally at breakers generally at transitions overhead line - cable generally at the entrance of overhead lines into a station usually in the HV-bushing area of transformers additionally at breakers overhead lineGtowerportalSurge arrestercableGIStrans-formerGIScable generator1234 Page 32 May 2012 2009 Siemens Energy, Inc.