Hardware implementation of enhanced generator loss of excitation protection scheme

Abstract

Loss of excitation (LOE) protection is one of the important generator protection scheme used to detect abnormal operating condition resulting from loss of field voltage. The conventional protection scheme is prone to incorrect operation during stable swings. Several enhancements to the conventional protection scheme are discussed in literature to improve the reliability of LOE protection scheme. This paper discusses the implementation aspects of one of the enhanced loss of excitation and power swing blocking scheme, to identify stable power swings (SPS). The performance of the enhanced scheme is validated by implementing it on a Numerical Relay Development Environment. The simulation results suggest that the modified scheme along with power swing blocking scheme does not add significant burden on the existing numerical hardware and the scheme can be implemented with modifications only in the firmware of the relay.