Different Methods for Enhancing Distance Relay Performance in Series Compensated Transmission Lines

Authors

  • Anjali Purohit
  • Vijay Gohokar

Abstract

The electrical power grid is undergoing a continuous revolution due to ever increasing dependence of modern society on electrical power and hence protection of such a wide, complex dynamic power system is a big challenge for protection engineers. Power transmission is highly susceptible to the various kinds of faults and their protection is very essential to increase reliability and security the of power system. Transmission lines are loaded closer to the threshold value of their thermal and stability limits. Installing fixed or controllable compensation capacitor in series with the transmission lines provides a vital solution for this. Compensation systems help to increase transient stability limits of power grid, enhance power transfer capability of transmission lines, reduce losses, optimize power-flow and improve its power-quality. With increasing popularity of power electronics, Flexible AC Transmission Systems (FACTS) are widely used as compensation systems for transmission lines. However, protection of compensated transmission lines is a crucial task as compared to uncompensated lines as inserting capacitors in series with transmission lines change magnitude and direction of fault currents and voltages. This has a large impact on the operation of protective relays and fault locators. Distance relays which are popularly used for the protection of transmission lines mal function due to wide variations in post fault voltage and current values. Several practical and theoretical schemes have been developed by the researchers to improve the performance of distance relay connected in series with the transmission lines such as Higher Order Statistics, adaptive Kalman filtering, discrete wavelet transforms, travelling wave schemes, fuzzy logic, Artificial Neural Network and many others. This paper is an attempt to throw light on these various methodologies in terms of their merits and demerits.

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Published

2020-02-09

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Section

Articles