ABSTRACT

Relay protection constitutes a major part of any power system that provides for continuous control of the main operation modes of power system elements and generates tripping commands for the failed parts or elements of the system. Faulty operation of relay protection owing to internal malfunctions can lead to the development of massive failures and even to the collapse of the power system with huge attendant financial losses. For this reason, the performance of the relay protection has to be periodically tested. There exists a vast variety of relay protection devices with different operating principles and construction. 1 Lately, all but digital protective relays (DPRs) have been completely driven out of the market. The choice of DPRs has been driven by various reasons and not at all by their absolute advantage over electromechanical or analog electronic devices. DPRs based on various principles of operation have their advantages and disadvantages.2–4 However, one of the problems is the complexity of the procedures for testing their operation.