Real-time simulation for relay performance evaluation

With the introduction of high-speed relaying systems, the need for extensive testing of these systems for different fault and abnormal conditions has become more important, to ensure the security and dependability of the electric power systems. Testing of relays can be summarized into three groups: steady state, dynamic and transient. While the first two types are performed during bench testing, they are not adequate for performance evaluation of subcycle modern relays. Transient testing is performed for verification of relay performance under transient conditions of power system to address such requirement. ABB has been using real-time simulations of power systems, for relay performance evaluation, for around seventy years in the US. This paper discusses the methodology employed for real-time simulations of power systems with different technology, with specific focus on the state-of-the-art real-time digital simulator from EDF. Specific case study related to the performance evaluation of a line relay system is discussed in this paper.