Relay panel ----- Control panel --------- Function as Event Remarks expected Indication / flag relay Ch Alarm 87 T faulty 87T D.C supply ---- MCB off Transformer main protection Ch --- [ ] yes faulty 50 / 51 P faulty 50 / 51 P D.C supply -------- MCB off Transformer back up protection 51 N faulty 51 supply ----- MCB off Ch --- [ ] yes faulty Transformer neutral current 51 NA faulty 51 supply ------ MCB off Ch --- [ ] yes alarm faulty 50S / 51S – 50NS / 51NS 50S / 51S – 50NS / 51NS D.C.supply ----- Transformer back up l.v. Ch --- [ ] yes faulty MCB off protection faulty 87 T off CH -- Tr back up faulty DCDB 50 / 51 P off [ ] Yes MCB trip 51 N CH -- Tr back up protection faulty DCDB switch MCB off alarm also 50S / 51S – 50NS / 51NS CH -- Tr back up l.v. protection faulty come in 51 NA CH -- Tr neutral current alarm faulty common Switch off ------ R2 DC supply fail [ ] Yes Transformer back up protection CH -- panel faulty DCDB switch off MCB - R2 DC supply fail [ ] Yes S2 DC supply fail [ ] Yes Switch off ------ Transformer mech protection CH -- faulty DCDB switch off MCB - S2 DC supply fail [ ] Yes Switch off ------ CBF supply fail [ ] Yes CH -- CBF protection faulty CBF supply MCB off in CBF supply fail BBCHZ panel
Event Relay panel ----- Control panel --------- Remarks Function as expected Indication / flag relay Ch Alarm 87 T faulty 87T D.C supply ---- MCB off Ch --- Transformer main protection faulty [ ] yes 50 / 51 P faulty 50 / 51 P D.C supply -------- MCB off 51 N faulty 51 supply ----- MCB off Ch --- Transformer back up protection faulty [ ] yes 51 NA faulty 51 supply ------ MCB off Ch --- Transformer neutral current alarm faulty [ ] yes 50S / 51S – 50NS / 51NS faulty 50S / 51S – 50NS / 51NS D.C.supply ----- MCB off Ch --- Transformer back up l.v. protection faulty [ ] yes DCDB switch MCB off 87 T off CH -- Tr back up faulty DCDB MCB trip alarm also come in common panel [ ] Yes 50 / 51 P off 51 N CH -- Tr back up protection faulty 50S / 51S – 50NS / 51NS CH -- Tr back up l.v. protection faulty 51 NA CH -- Tr neutral current alarm faulty Switch off ------ R2 DC supply fail CH -- Transformer back up protection faulty [ ] Yes DCDB switch off MCB - R2 DC supply fail [ ] Yes Switch off ------ S2 DC supply fail CH -- Transformer mech protection faulty [ ] Yes DCDB switch off MCB - S2 DC supply fail [ ] Yes Switch off ------ CBF supply fail CH -- CBF protection faulty [ ] Yes CBF supply MCB off in BBCHZ panel CBF supply fail