which fault current is maximum: 3 phase short circuit, LG,
LL or LLG?? why??
in one of the problems that i have solved, 3 phase short
circuit current on an unloaded generator came out to be
less than the LG fault current. can anybody please explain
why.
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Answer Posted / dr rajan
It is always the 3 phase bolted fault. Check your problem
again. You may have made a mistake. Why 3Ph fault current is
high?
When all phases are grounded or shorted, the impedance is just
let us say X in each phase leading to V/X x 3 times. where as
when you have LG, you will include the line impedance in
series with X, equals X+xL, which is more than X on 3Ph short
ckt. When you divide V/(X+xL) what will you have???? More
current or less current???????
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