Experimental study on minimum approach distances and complex gaps for helicopter live-line work on 1000kV transmission line

The helicopter live-line work is one of the most important technical measures adopted in the technical field of operation and maintenance on the electric transmission lines .In order to provide technical parameters and to ensure its safety for helicopter live-line work on 1 000kV transmission lines, the typical working conditions of actual operation was arranged with full-scale simulated helicopter. The live-line work gap discharge test were conducted for the 1 000 kV transmission line, so as to obtain live-line work gap discharge characteristics of all typical working conditions, to determine the lowest discharge position during the equipotential approaching process. According to the calculation method of live-line work approach distance on AC transmission line, to ensure live work risk to be less than 10-5, the minimum approach distance and complex gap for helicopter live-line work on 1 000kV transmission line at the altitude of 1 000 m and the below areas was calculated.The minimum phaseground approach distance and complex gap was 6.8 m and 7.3 m, the minimum phase-phase approach distance and complex gap was 9.2 m and 9.5 m.