Generator Circuit Breaker


Thread Starter


Why is GCB placed after GT and not in between Generator and Generator transformer(GT)?
It is not in all the cases GCB is mounted after GT. When the generator size is less say 5 MW then we can have GCB 500A breaker for 13.8kV (5x1000/1.732x13.8). However when the Generator size is high say 500MW then the GCB current rating is as high as 12000A at 25kV (500 x 1000/1.732x25). Huge size. Generator will have filed breaker. For any fault between generator and GT, GCB, field breaker will be trip and tripping sequence differs taking into consideration mechanical system turbine etc.
Dear Bala,

Thank you very much for your reply. Now I've got a somewhat clear idea about GCB. If you know more about it, you can send it to me. (priyamanavan_gy @ zapak. com)

Thank you.