protect the generator from power grid

[tareksabry]

we have a new plant in our factory it is a steam turbine which driven the generator,and it has it protection device,it`s done by Chinese engineers so they told me that the feeder of power grid should be connected always at same time with the generator while it is supplying the plant,some other peoples told me that we must have a protection device which protect the generator from the power grid like over voltage under voltage over freq. under freq. reverse power etc. so could any one help me in this issue.

 

[slavag]

Hi .
I think we had here some misunderstanding
OP:
"we have a new plant in our factory it is a steam turbine which driven the generator,and it has it protection device,it`s done by Chinese engineers so they told me that the feeder of power grid should be connected always at same time with the generator while it is supplying the plant,some other peoples told me that we must have a protection device which protect the generator from the power grid like over voltage under voltage over freq. under freq. reverse power etc. so could any one help me in this issue. "
Tareksabry, as I understood, you have some generator protection, not important, what company, it;s part of generator supplier.
But you work in co-generation with the grid ( I suggest via GSU, step-up transformer).
Problem isn't generator protection, problem is loss of main protection, that means, dissconnect of grid CB on the feeding SS and fast or slow autorecloser.
Here you have so much options:
Your generator capacity is enough for plant feednig,
isn't enough, that means after decoupling from the grid, you have provide load shedding, etc.
Possible option du-feedeng, to grid and from grid.
All this points are influence on the LOSS OF MAIN protection, in lot of case it's dedicated protection and isn't part of generator protection, in the generator protection we usually use two standard protection : frequency decoupling level and ( if it request by utilities) pole slip/out-of-step.
Best Regards.
Hope that help
Slava

 

[YuriSarcas]

It sounds like you are running in a Cogen or Peak/Shave mode.

I have used many GE Multilin Relays and they work well. They will have pretty much any protection you need in them and they are fully configurable with a computer. They also have Ethernet and RS485 connections if you need it to talk to a SCADA system. The good is that it is just one relay. The bad is that it is just one relay, it fails you loose all protection.

I am not sure which relay you would use for your application since I ussually work with Diesel gens but they should have something for your Turbine protection and your Utility Protetion. I would check with your Utility first on what relays they approve for your use.