Power Flow study- Short Ckt calculation
Power Flow study- Short Ckt calculation
(OP)
Have a question on short circuit study on our system.
Shown in a 115 kV system model. The model is missing a generator synch breaker at Point A and we are interested in the maximum available fault as seen by this breaker. The model calculates the fault on 115 kV Bus (say point B). Is this fault going to be same as the fault seen by the breaker at point A?
Shown in a 115 kV system model. The model is missing a generator synch breaker at Point A and we are interested in the maximum available fault as seen by this breaker. The model calculates the fault on 115 kV Bus (say point B). Is this fault going to be same as the fault seen by the breaker at point A?






RE: Power Flow study- Short Ckt calculation
If this impedance is small, and it probably is relative to transformer impedances, then the fault levels will be similar.
RE: Power Flow study- Short Ckt calculation
It also depends where the fault is. A fault on bus side of the breaker will only see contribution from its own generator. A fault on line side of the breaker will see fault currents from rest of the system (all other sources).
Rafiq Bulsara
http://www.srengineersct.com
RE: Power Flow study- Short Ckt calculation
RE: Power Flow study- Short Ckt calculation
Redfurry/Rbulsara
I agree with your point. Other than the impedance of the line between A & B, the maximum fault seen by the breaker should be same as far as I can see. Rbulsara, I didn't mention the point about the fault since I am interested in the maximum available fault that the breaker needs to interrupt, whichever side it is from.
Davidbeach
Thanks and you mention an interesting point. The X/R that our system uses is around 38-39 which is high. However, are you referring to the X/R multiplier used to convert symmetrical current to asymmetrical? It sounds like the fault of 44 kA for you is symmetrical and your asymmetrical rating is 65 kA. Other than this I am not familiar with any other multiplier ratio. Any article on this?
RE: Power Flow study- Short Ckt calculation
RE: Power Flow study- Short Ckt calculation
This is only a curiosity:
Are connections Y-Y grounded-grounded,ungrounded-grounded or ungrounded-ungrounded?
RE: Power Flow study- Short Ckt calculation
RE: Power Flow study- Short Ckt calculation