Line differential protection systems based on low power stand alone current sensors

This paper presents a novel solution for the protection of high-voltage power cables based on differential protection principles with currents measured by Rogowski Coil current sensors. This solution has been designed for implementation on four in-service 220 kV power cables that interface a gasinsulated substation (GIS) with overhead transmission lines. The protection scheme has been subjected to extensive testing in a high power laboratory and in a field application that provided extreme power system operating conditions. All tests have verified the high dependability and security of the solution.