A Loss-of-Field Detection Relay Based on Rotor Signals Estimation

This paper 1) introduces a new approach for dependable and secure detection of loss-of-field (LOF) events based on estimating rotor signals, 2) implements digital algorithm of the corresponding LOF relay in an industrial hardware platform, and 3) evaluates performance of the LOF relay in a real-time digital-simulator (RTDS) based control-hardware-in-the-loop (CHIL) environment. The main features of the proposed relay as compared with the conventional approaches include 1) capability to discriminate between system disturbances and LOF events, and 2) dependability and higher speed of the LOF detection mechanism. To evaluate the proposed approach performance for various types of LOF events, a detailed excitation system is modeled and implemented in the RTDS-based CHIL environment. This paper also verifies superior performance of the proposed LOF relay as compared with that of a conventional impedance-based LOF relay, using the RTDS-based CHIL platform.