Core Balance Current Transformers

These are ring type CTs & suitable for the measurement of the sum of three phase currents in a 3-ph cable. Under normal operating conditions this sum is zero. In the event of an earth-fawt the sum of the current is equal to the zero sequence current. These CTs are generally used with English Electric make CTUM 15 static relay. It is necessary to specify leakage current to be detected along with minimum setting of the relay and size of cable at the time of ordering CT.