papa smurf
Member
Dear forum,
I have situation in Iraq where I'm inspecting a sub-station that has national grid with generator backup. At this time there is no grid power coming to the plant and there using the generators for prime power. We have 5 - 1.2 mega watt generators fed from a 3 pole breaker at the generator which feeds a DYN11 - 1250 kva 3 phase delta-Y transformer with 400 volts. It steps up to 11k volts going to a substation with generator breakers, group breaker, main breaker and downstream breakers that feed other transformers at various locations on base and steps back down to 400volts. My 1st question is should the contractor run a neutral from the generator to the transformer. At this time the contractor has the neutral bar at the generator breaker with a green ground going to a ground rod. He did not run a neutral wire to the transformer. He says it is not necessary. My issue is the contractor tells me that when 1 generator is running that the the substation breakers for the remaining 4 generators stay in the closed position which in turn back feeds to the transformers and to the generator. The Iraqi electrical Eng. tells me they needed to do that so they could read the digital readouts at the generators and to sync. them. But he tells me this system is not automated and they do this in manual. I will say we did have a hard time communicating with each other. His English was not good and I understand they brought him in because the org. contractor left with all the info and passwords for the sync. system. So he bypassed the system some how but i did not have time to trace and figure out what he had done. My question is does any of this sound correct as far as the back feeding to the generators are concerned. Your help will be greatly appreciated.
I have situation in Iraq where I'm inspecting a sub-station that has national grid with generator backup. At this time there is no grid power coming to the plant and there using the generators for prime power. We have 5 - 1.2 mega watt generators fed from a 3 pole breaker at the generator which feeds a DYN11 - 1250 kva 3 phase delta-Y transformer with 400 volts. It steps up to 11k volts going to a substation with generator breakers, group breaker, main breaker and downstream breakers that feed other transformers at various locations on base and steps back down to 400volts. My 1st question is should the contractor run a neutral from the generator to the transformer. At this time the contractor has the neutral bar at the generator breaker with a green ground going to a ground rod. He did not run a neutral wire to the transformer. He says it is not necessary. My issue is the contractor tells me that when 1 generator is running that the the substation breakers for the remaining 4 generators stay in the closed position which in turn back feeds to the transformers and to the generator. The Iraqi electrical Eng. tells me they needed to do that so they could read the digital readouts at the generators and to sync. them. But he tells me this system is not automated and they do this in manual. I will say we did have a hard time communicating with each other. His English was not good and I understand they brought him in because the org. contractor left with all the info and passwords for the sync. system. So he bypassed the system some how but i did not have time to trace and figure out what he had done. My question is does any of this sound correct as far as the back feeding to the generators are concerned. Your help will be greatly appreciated.
Wish I could help more.