A Combined Digital Distance Relaying Algorithm and Its Performance Evaluation

Abstract

Power system protective relays protect electric systems against system faults and abnormalities. Due to increasing advantages of digital relay algorithms, nowadays modern power system protective relays are mostly microprocessor based. Digital based algorithms are used in these relays to implement different relaying schemes. In this article, a combined method using a combination of both differential equation and least square error algorithms is presented. The proposed method is explained analytically and modeled appropriately. Simulation results are presented to illustrate effectiveness of this combined algorithm for transmission line distance protection. Performance of the proposed algorithm was also investigated using some recorded fault data. Efficiency and reliability of this method could be perceived by the obtained results.

Keywords:

• distance protection
• digital relay
• differential equation algorithm
• least error square
• recorded field data

Acknowledgments

The authors are grateful for the recorded field data provided by the Alberta Power Ltd. Support of the Control and Intelligent Processing Center of Excellence, University of Tehran is also acknowledged.