Distance Relaying Algorithm for Double-Circuit Transmission Line with Compensation for Reactance Effect under Standard Availability of Measurements
This paper deals with non-pilot distance protection of a double-circuit transmission line. Negative impact of the reactance effect, appearing in. measuring a fault loop impedance,, On Operation of the relay is discussed. An adaptive algorithm allowing one to prevent the relay from mis- or mal- operation caused by the reactance effect is introduced. The algorithm. is designed for a standard availability of measurements from one end of the double-circuit line, i.e. when three-phase voltage and current from the faulted line circuit., and additionally zero-sequence current from the healthy line circuit, are provided as the relay input signals. The algorithm is based on changing the position of the distance relay characteristic in such a. way that the reactance effect is effectively compensated for. For this purpose the shift vector is determined in on-line relatively simple calculations. The delivered adaptive algorithm has been tested using current and voltage signals obtained from simulation of varies faults using the ATP-EMTP software program. Selected results of the evaluation are presented.
double-circuit transmission line reactance effect distance protection fault fault loop impedance measurement adaptive characteristic