Protective gap operating type of live working for EHV and UHV transmission lines considering elevation factors

Abstract

In order to provide technical support for the model selection and practical operation of protective gap of live working for transmission lines, we adopt a method for insulation coordination to obtain that the protective gaps for 500 kV, 750 kV and 1 000 kV voltage transmission lines at altitude of 1 000 m and below are 1.6 m, 2.2 m, and 4.0 m, respectively. When using conventional research methods, in order to meet safety requirements of live working, we need to adjust electrode structure of the protective gap and restart switching impulse test of the protective gap and operational gap. The calculation results show that the protection scopes of protective gap for 1 000 kV and 500 kV transmission line are about 0~1.8 km and 0~1.7 km, therefore, we need to install protective gap on the work phase of adjacent tower of operation point. The research also shows that replacing protective gap with transmission line arrester with air gap is not feasible, because of the great differences in air gap structure and discharge characteristics between them. The research achievements can provide technical support for the operation of live working mode of protective gap.