co-generation transformer

[Cold Fusion]

I got asked about what transformer would be used for a co-gen plant connection to a utility. Plant generates about 1MW at 480V Wye, 3ph, utility is 29KV. If the plant is down, it draws a few kw. As I understand, there is no separate service for hotel loads.

I'm thinking it should be a 480D/29kvD, with the 489V grounding/bonding taking at the generation switchboard and the 29kv side is what ever the utility has. Second choice is 480Y/29kvD. But I can't figure out what to do with the Y point.

It was a casual conversation, not part of of my job - but it got me thinking. What say our transformer/distribution/utility wizards?

cf

 

[charlie]

You need to be talking to the serving electric utility to see exactly what they want. Since you will be feeding back into their lines, they will give you their specifications and anything you get here will probably be wrong. :smile:

 

[Cold Fusion]

Thanks charlie. if I were putting one in, I would be working with the utility - but I'm not. Just curious how one might do this.

richxtlc, Jim, templdl, one of you has some ideas and why

cf

 

[72.5kv]

Recent project I was involved in. Similar situation as yours.

6 X 1.5MW 4.16kV/2400 Genset. GSU 4.16Kv d-24/13.8kV 15MVA

Genset were grounded through a resistor to limited close in ground fault current. There is a laundry list of relays needed to protect the gensets. The line leaving the plant is protect as if it were a transmission line. This now involves pilot relaying to trip 24kV rated breakers at both the source and recieveing end of the line.

 

[charlie]

. . . Just curious how one might do this. . .

Take a look at these documents on Level !, 2, & 3 Distributed Generation about 5 lines down. The applications may give you a feel for the information an electric utility would want to do this, the how is not addressed.