A New Fault-Impedance Algorithm for Distance Relaying on a Transmission Line

• Published in: IEEE transactions on power delivery Vol. 25; no. 3; pp. 1384 - 1392
• Main Authors: Zhen Yu Xu, Xu, G, Ran, Li, Yu, S, Yang, Q X
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.07.2010; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Algorithms; Applied sciences; Connection and protection apparatus; Current measurement; Distance relaying; Disturbances. Regulation. Protection; Electric potential; Electrical engineering. Electrical power engineering; Electrical power engineering; Electrical resistance measurement; Exact sciences and technology; fault path resistance; fault-impedance measurement; Faults; Impedance measurement; load current; Mathematical analysis; Phase measurement; Power networks and lines; Protective relaying; Relaying; Relays; Robustness; transmission line; Transmission line measurements; Transmission lines; Voltage; Performance evaluation; load current; Protective device; Relay protection; Algorithm; Fault currents; Distance relaying; Transmission line; fault path resistance; fault-impedance measurement; Power system protection; System simulation; Electric fault
• ISSN: 0885-8977; 1937-4208
• DOI: 10.1109/TPWRD.2010.2042082

This paper describes a new algorithm to calculate the per phase impedance between the measurement and fault points on a transmission line, featuring robustness to the uncertainties in load current and fault path resistance. The algorithm, which is ideal for distance relaying, is derived based on a justifiable assumption of the fault path being purely resistive, implying that the unmeasured fault point voltage and fault path current are in phase with each other. This paper illustrates the characteristics of the proposed algorithm and evaluates its performance by using PSCAD/EMTDC simulation.