Realization of Distance Relay Algorithm using EMTP MODELS

Digital technology has advanced very significantly over the years both in terms of software tools and hardware available. It is now applied extensively in many area of electrical engineering including protective relaying in power systems. Digital relays have many advantages over the traditional analog relays. The digital relay is able to do what is difficult or impossible in the analog relays. However, the complex algorithms associated with the digital relays are difficult to test and verify in real time on real power systems. Although non real-time simulators like PSCAD/EMTDC are employed to test the algorithms, such simulations have the disadvantage that they cannot test the relay dynamically. Hence, real-time simulators like RTDS are used, but the latter needs large space and it is very expensive. This paper uses EMTP MODELS to simulate the power system and the distance relay. The distance relay algorithm is constructed and the distance relay is interfaced with a test power system. The distance relay’s performance is then assessed interactively under various fault types, fault distances and fault inception angles. The test results show that we can simulate the distance relay effectively and we can examine the operation of the distance relay very closely including debugging by using EMTP MODELS.