how to calculate restraing current and operating current
for differential protection if 20 mva transformer is OLTC
33 kv/11 kv ? and what should be the type and ratio of CT?

Answer Posted / nur.asidik

let call Irestrain as Itot, because different relay have different characteristic to define Ires.
for micom P54x, Itot =(|I1|+|I2|)/2,
for sepam T87, Itot =Max(|I1|,|I2|)
where I1=primary current
I2=secondary current,
it need to be consider to calculate transformer ratio factor

Is This Answer Correct ?    1 Yes 0 No



Post New Answer       View All Answers


Please Help Members By Posting Answers For Below Questions

Leakage current,un balance current which relay using for high voltage transmission?

1643


How we can calculate the life of Lead acid battery

1316


how to differentiate a mpcb,mcb with a contactor? Explain their working operation

1656


HOW MUCH CURRENT DOES SYNCHRONOUS MOTOR TAKES AT SYNCHRONOUS SPEED IN NO LOAD CONDITION ?

1450


Control cables in S's will carry 1000v which is AC R DC? Pls answer meĀ 

1607






How to checked frequency drive output voltages?

696


what is negative d.c. voltage, why this voltage is used in base transciever station.

1744


how to calculate the fault in substation

1728


what is an unbalance in acircuit? in a three phase 3wire circuit how an unbalance will come? in a three phase four wire system how an un balance is coming?

1353


i want to know that how the height of Ct ,cvt ,LA calculated on the basis of creepage distance

2058


Assuming that a dedicated neutral earthing transformer is provided for each GT generator, when the two generators are running in parallel, has consideration been given that the earth fault current from one generator stator winding be split between the two neutral earthing transformers? If so, what adverse impact will this have on the operation of the 59N and 27TN devices?

1234


features of hbc fuses

1947


Define the three phase formula fuse.

1407


In a single how much maximum current and watts using

1652


Is electro plating what type of load whether resistive, inductive or capacitive loads

2907