Hello everyone. I am new college pass out. I got some electrical drawing and calculated the short circuit but there is variation between my calculation and the contractor calculation. Here I have attached my calculation please comment on it (Not a home work question). I want to know any other factor to be included in the calculations. I made my calculation as per IEC 60909.
22kv Line ,z=1.29,Cmax=1.10 and Cmin=1.0
MAXIMUM SHORT CIRCUIT CURRENT
INITIAL SYMMETRICAL SHORT-CIRCUIT CURRENT =Cmax * 22000/(1.732 * 1.29)
=1.10*22000/2.23
=24200/2.23
=24200/2.23
Ik"
= 10852.01A ~ 11KA
PEAK SHORT CIRCUIT CURRENT (Ip)
=K * 1.414 * 10852.01 (value of k obtained from graph)
=1.6 * 1.414 *10852.01
= 24551.58 A
MAXIMUM SHORT
CIRCUIT AVAILABLE AT 22 KV = 24551.58 A ~25KA
MINIMUM SHORT CIRCUIT CURRENT
INITIAL SYMMETRICAL SHORT-CIRCUIT CURRENT =Cmin * 22000/(1.732 * 1.29)
=1*22000/2.23
=22000/2.23
Ik" =
9865.47A~ 10KA
Should i calculate the first peak of the fault current for minimum fault current (Ip) or go a head with the initial symmetrical fault current Ik" (ie minimum Fault current =10KA)
PEAK SHORT CIRCUIT CURRENT (Ip)
=K * 1.414 * 9865.47 (value of k obtained from graph)
=1.6 * 1.414 *9865.47
= 22319.63 A~23 KA
MINIMUM SHORT
CIRCUIT AVAILABLE AT 22 KV= 22319.63 A ~23 KA
Comments on Short Circuit Calculation Needed
Re: Comments on Short circuit calculation needed.
