Measurement of secondary arc current in transmission lines employing single phase switching

Single phase switching (SPS) is widely used on extra high voltage (EHV) transmission lines. The effectiveness of SPS in maintaining power system stability is largely determined by the speed with which secondary arc extinction, and hence autoreclosure, can be achieved. Two factors which govern the probability of secondary arc extinction are the secondary arc current and the rate of the rise of the recovery voltage. Successful application of SPS requires keeping the magnitude of the secondary arc current below a certain level. The purpose of this paper is to present a method for the measurement of the secondary arc current on a double-circuit transmission line employing SPS. The model developed for the double-circuit line takes into account the mutual coupling between the two individual circuits. Both distributed and frequency dependent parameters are considered. A typical 400 kV double-circuit line is considered and the effective value of the secondary arc current is evaluated for both transposed and untransposed configurations of the line. The simulation results compare favorably with the results available from simple network analysis.