The application of powerful microprocessors DIGITAL MICROPROCESSOR BASED
RESTRICTED EARTH FAULT RELAY (REFR) opens a new chapter for power system protective
relaying. The digital processing of measured values and the ability to perform complex
arithmetic and logic operations, give digital protection relays significant performance and
flexibility improvements over their traditional analogue counterparts. Additional
advantages - very small power consumption, adaptability, self-supervision, smaller
physical construction and selectable relay characteristics - all combine to allow the
implementation of accurate and highly reliable protection schemes at a significantly
reduced financial burden.