An ultra-high-speed method of fault detection and its application to power swing blocking in digital distance protection

Abstract

Conventional approaches to blocking distance relay operation during power swings rely upon the slow movement of the impedance measured by the relay during electromechanical changes in the power system as compared to the fast movement of impedance measured during a fault. This paper describes an ultra-high-speed fault detection process which is capable of differentiating between genuine faults and apparent faults caused during power swings. Use of the fault detection process in a digital distance relay allows the relay to be enabled for genuine faults but inherently blocked for power swings.