Testing EHV secondary arcs

The protection of the environment requires compact EHV tower constructions. This trend results in decreasing the clearances and phase-to-phase distances. It is expected, that both the number of faults and the amplitude of the secondary arc current will grow in the future. All these make it necessary to improve the efficiency of single-phase reclosing. Secondary arc duration values gained at field tests show a big spread and therefore they do not provide a reliable basis for selecting a suitable dead time. Analyzing the main processes affecting the secondary arc duration, the authors conclude that traveling wave phenomena arising in the intermittent period of secondary arcing have a determining effect on the arc duration. Considering the difficulties connected with field tests and the big influence of the weather conditions on the secondary arc duration, the authors propose to complete laboratory test circuits by such components, which affect the simulation of the wave processes. A method for the detection of the secondary arc extinction on 750 and 400 kV lines is mentioned, which offers a possibility to prevent inefficient reclosures