plz explain TSM and PSM.with example suppose ct ratio is
4000/5 and tsm is .15 and plug is at 3.75 if fault current
is 8000A.so how i find relay oprating time.
Answer Posted / yvb
your PSM set for 3.75 means 3.75 times of your py.
current. if fault current is 3.75 times of 4000 i.e 3.75 x
4000 = 15000 A. your relay will operate in 0.15 sec.(
Primary Injection.)on Secondary we can say 5 x 3.75 =
18.75A flows through ur relay.
Now comming to ur case if fault current is 8000A ie. 2
times of 4000 or u can say 2 times of 5 A.
Then your relay will operate in 0.282 seconds.
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