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Case Study – When Single cable was found hotter than 3 core cable

Case Study u2013 When Single cable was found hotter than 3 core cable

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Case Study – When Single cable was found hotter than 3 core cable

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  1. ISO 9001:2015 ISO 45001:2015 (OH & S) Certified Company Case Study When Single cable was found hotter than 3 core cable www.systemprotection.in +91-265-2225137

  2. Beingintheservice, wealwaysusedtoget variouscallsregardingproblemintheir plants. However, theywereluckythatthis problemdidn’toccuronSundayorHoliday (Majorityofthebreakdownoccurredon thosedaysonly). Jokesapart, wegotthese callthat, theirpowercableisgetting heatedup. Wetookfewdetailsoncalland askedforphotos. Theclienthad3RX3CX185SQMM, XPLE ArmouredCablewiththeearthingbraid connectedtotheearthbus-baratboth endsofthecable. Cableterminationwasas perdrawingshows. Inabovefigureconsiderthenomenclature asC1RisR-PhofthefirstCablerun, C2Yis Y-PhoftheSecondCablerunandso-on. Aftersomemaintenanceactivityandsome consideration, theyhavereconnectedthe cablesfrombothendasfollows: Inaboveconnection, clienthasterminated allcoresoftheFirstruntoR-Ph, Secondrun toY-PhandThirdruntoB-Ph. Thiswas doneconsideringthattherearethreecable ofthesamesizeandfinalcross-sectionarea providedbyreachcabletoeachphase remainssame. Afterobservingtheinstallationofthe cables, itwasconcludedthatallthecables armourswereconnectedtotheglandplate withEarthingBraidsatboththeends. Thedifferencebetweenfirstinstallationof thecableandthelaterinstallationofthe cableisthat, infirstinstallationduetothe three-phasecoreareinonecable, resultant fluxlinkagetothearmourisnull. Afterputtingtheaboveconnectedcablesin service, andwiththetimelapsed, clienthas foundthattheGlandPlateisgetting carbonizedatGlandsduetoheatingup. www.systemprotection.in +91-265-2225137

  3. Whereasinthelatercase, eachthree-phase cableservesasasinglecorecableandflux linkagetothearmourgeneratesEMF. This EMFinturngeneratedcirculating/eddy currentsinarmouroncetheclosecircuitis formed. InLatercasethisclosedcircuitis formedthroughArmour – EarthingBraidat oneend – Earthing – EarthingBraidatother end – Armour. Duetothiscontinuously flowingCirculating/eddycurrentinPlates, it isheatedupandcarbonizingisobserved. Suchkindsofproblemarereportedmorein singlecorecableof11 / 22 / 33kV, where, by mistakeorunknowingly, engineersconnect earthingbraidwithearthingatbothends. Thus, itisrecommendedtoearthonlyone endofsinglecorearmouredcable. Wehope, thiscasestudywillhelpandifyou haveanysuggestionsdoletusknow. Solutiontotheproblemisthat, anyhowwe havetoopenthisclosedcircuit. Wecando thatbydisconnectingOneearthingbraid withearthatanyendoftheCable. www.systemprotection.in +91-265-2225137

  4. CONTACT INFORMATION 301/2/306, SilverlineComplex,OppositeBBC Tower,Sayajigunj,Vadodara - 390005, Gujarat, India. bdm@systemprotection.in www.systemprotection.in +91-265-2225137

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