Calculate Three-Phase Short-Circuit Current using Python

edit

SCMU solves networks with unbalances, a 3 phase fault is solved as you said, a LG on phase A plus a LLG between phases B and C and ground. You can use the activity ASCC (psspy.ascc_3) to compute 3 phase short-circuit calculations. Other options is the IECS activity.

The following code calculates the 3 phase fault current at bus 154 in savnw.sav and writes the result to a text file:

buses = [154]
psspy.bsys(1,0,[0.0,0.0],0,[],len(buses),buses,0,[],0,[])
psspy.ascc_3(1,0,[0,0,0,0,0,1,0,0,0,0,1,0,0,0,0,0,0],1.0,"ascc3P.txt","","")

The file contains the pu current, 69.0545 pu.

  3    154                        69.0545        3.7513  DOWNTN      230.00

Use Ibase=Sbase/Vbase/sqrt(3) = 100/230/sqrt(3) = 0.251022 kA to convert to kA. 69.0545*0.251022 = 17.334 kA.

You can complete the script to rewrite the file with the fault current in kA instead of pu.