Answer / manisand1

CT resistance = 1.8ohm,
Lead resistance = 4.0 ohm,
Starting current = 195*5/200 = 4.875 Amp
Starting voltage = 4.87(1.8+4)= 28.275 = 28.3 volts
This is to be set to 30Volt,

But please remember that knee voltage should be 60 volt
minimum.

For anymore clarification you can mail me to :-
manisand1@hotmail.com

Answer / puneet prashar

Knee Voltage=2X Earth Fault current(RCT + RW)/CT
Trasformation ratio

Where
RCT= CT impedeance as per manufacture1.02
RW = Wire resistance as per manufactre
say.oo32/metre then RW= 2X 200mtr X .0032

CT transformation ratio= 4000/1=4000
4000/5=800

VKnee= 2X58000(1.02+1.28)/4000 or 800 depending upon ct used

Vknee= 66.7v

Vknee> relay stability Voltage

Relay stability voltage formula will be given by relay
manufacturer as every relar manufacturer has their own formulas

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