X/R ratio of Generator
X/R ratio of Generator
(OP)
Dear Folks,
I have started power system modelling very recently. For generator modelling, in X"/R -ratio, which resistance we have to consider? between phases or phase to neutral (for star winding generator)
I tried with both resistances for calculaing Transient and sub-transient fault currents but not matching with Generator supplier's fault current data which is attached.
The generator manufacturer has given max. 3ph. Symm.S.C. current:8314A (Is it steady state fault current or Transient fault current).
Your reply will be highly appreciated.
and thanking you.
I have started power system modelling very recently. For generator modelling, in X"/R -ratio, which resistance we have to consider? between phases or phase to neutral (for star winding generator)
I tried with both resistances for calculaing Transient and sub-transient fault currents but not matching with Generator supplier's fault current data which is attached.
The generator manufacturer has given max. 3ph. Symm.S.C. current:8314A (Is it steady state fault current or Transient fault current).
Your reply will be highly appreciated.
and thanking you.






RE: X/R ratio of Generator
RE: X/R ratio of Generator
RE: X/R ratio of Generator
Advanced thanks..
RE: X/R ratio of Generator
Don't know why the LN fault or LL fault current increases after fault ? - Lack of damping?
RE: X/R ratio of Generator
Fault current should be reduced generally from sub-transient state to Steady state.
But in the attached decrement curves, as you said, L-L & L-G currents started increasing.
What are the possibilities?
RE: X/R ratio of Generator
A typical curve should be like the one I attached.
Don't know how and what they did to get the curve you may want to go back ask them the detailed modeling of both machine, exciter and fault.
Regards,
RE: X/R ratio of Generator
RE: X/R ratio of Generator
I will ask manufacturer, the reason for increasing trend of L-L and L-G fault over a period of time.
W.r.t. typical attached curve, what is the reason for increasing fault current after approx.0.1 sec.
RE: X/R ratio of Generator
RE: X/R ratio of Generator
Regards,