WHAT HAPPENS IN DIFFERENTIAL PROTECTION IF CT REACHES ITS
KNEE VOLTAGE POINT?

Answer Posted / tony

Normally the knee point voltage must be

Vk > 2*Vs

Where Vs is the calculated max. voltage appears across the relay.

Beyond knee point the chara of CT is no longer proportional to the primary current and this cause faulty measuring by relay.Thus if we have higher Vk we can easily with stand higher Vs(fault equivalent seen by relay)

Is This Answer Correct ?    0 Yes 0 No



Post New Answer       View All Answers


Please Help Members By Posting Answers For Below Questions

What is your acheivements

1677


how to size H.T & L.T Panel ?

1644


In convertor can we use rectifier thyristor in place of invertor thyristor with explain.

1382


what curve and rateing would you use for a three phase 0.75kw motor?

1569


what's the exact magnitude of current, flows through Neutral?

1549






what are types of encoder

1431


Whether amorphous core transformer is available in India?.If available then up to what rating of voltage and KVA?.

1303


Where I can get the sample question for post of Junior engineer electrical-II For RRB Bhubaneswar.

1702


what are the difference between PLC and embedded

1652


when the Transmission and Distribution network where is the "feeder" lines are located? and why should be used in T&D network.....

1263


What should be the protection scheme for a 15kw, 3-phase motor working in a lathe machine.

1572


What is the formula for selecting the cabels according to load? How to calculate what sq.mm cabel to be used?

993


how many types of motor can be used in washing machine

1685


What is inverse definite minimum time lag relay? Where is it use?

2300


How many types are using in 220kv/400 kv swith yard

1752