By:

Mr. Mohan Sawarkar

Mrs. Mohini Sawarkar

The basic principle of distance protection involves the division of the voltage at the relaying point by the measured current.

If the measured impedance is less than the reach point impedance it is assumed that the fault exists on the line between the relay and the reach point.

SIPROTECH 7SA522

ABB MAKE REL670&

650

AREVA MAKE MICOM

P441, P442

NUMERICAL DISTANCE RELAY FUNCTIONAL OVERVIEW

The numerical distance relays provide combination of reliability, selectivity, suitability, sensitivity, speed and compatibility with IEC61850 .

So ,we must retrofit old distance protection with numerical distance protection.