A Micro Computer-Based Methodology for Distance Protection on Long UHV Transmission Lines Using Symmetrical Components

This paper proposes a methodology for the long UHV transmission lines distance protection using microprocessor for fault detection, isolation and auto reclosing processes. In the present era, with the development of microprocessor technology, their extra efficient controlling and computing abilities can be utilized in distance relaying for efficient computing of fault distance and the type of fault occurred on the transmission line. Using Symmetrical component theory a single performance equation is developed that will encounter all type of faults on transmission lines regardless of the nature of the fault. Microprocessor will process on these sequence components to estimate the type of fault and the distance of fault from the relay. ETAP is used as a simulation tool to obtain the desired results. Although the formulation described here is independent of hardware yet it provides a complete analytical base for distance protection and is analyzed for different types of fault conditions using simulation tools.