I want to know what must the CT ratio be on a load of 300A
is a 3PH nutral to earh installation?

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I want to know what must the CT ratio be on a load of 300A is a 3PH nutral to earh installation?..

Answer / a.p.nanjappa

Load current is 300A. The equipment shall withstand the
starting current -which is around -5-8xIn.It is preferable
to select 1ooo-1200A/1A OR 5A.
WE ADOPT THIS THUMB RULE for our protection setting& co-
ordination.

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I want to know what must the CT ratio be on a load of 300A is a 3PH nutral to earh installation?..

Answer / wareagle

600/5 would work nicely. One on each phase.

Is This Answer Correct ?    3 Yes 4 No

I want to know what must the CT ratio be on a load of 300A is a 3PH nutral to earh installation?..

Answer / p_mehboobkhan

i want answer...

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I want to know what must the CT ratio be on a load of 300A is a 3PH nutral to earh installation?..

Answer / a.p.nanjappa

The neutral is a point in power transformer or in motor
connection where all phases are connected.In this point
voltage is zero. when you connect thisoint to earth, the
fault current or capacitance circulating current flows to
earth.
when a fault occurs , current is high.Therefore,CT ratio
should be 1000-1200/5 or 1A.

It is usually upto designer or protection device supplier.

Is This Answer Correct ?    0 Yes 1 No

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