A DIGITAL MULTIFUNCTION PROTECTIVE RELAY

This paper describes the development of a digital multifunction relay for the protection of the intertie between a customer-owned generator and a utility system. The relay uses state-of-the-art digital signal processing techniques to measure the relay parameters, thereby eliminating analog hardware. The hardware design uses a dual microprocessor architecture to achieve flexibility and high speed operation. The paper details the signal processing algorithms used and the relay software and hardware implementation.