Analysis of safe maintenance methods for 750kV four-circuit transmission lines on the same tower

摘要

The abstract should be suitable for direct inclusion in ABSTRACT: With the construction and development of the power grid in northwest China, 750kV four-circuit tower construction has become the optimal solution to the shortage problem of transmission line corridors. In order to ensure the safety of the maintenance of 750kV four-circuit transmission lines on the same tower, this paper makes a 1:1 simulation tower head according to the four-layer cross arm structure of the four-circuit transmission lines on the same tower. The gap discharge characteristics of the four-circuit transmission lines on the same tower under special live working conditions are obtained through tests. The minimum safe distances of the equipotential operators on the side of the tower to the tower body and the lower cross arm are determined to be 4.2m and 4.3m respectively, the minimum safe distance between phases is 5.8m, and the minimum combined gap distance between phases of the equipotential combination of the conductors entering and leaving the outside phase is 6.3m;;The simulation modeling calculation is used to obtain the maximum induced voltage of 64.5kV when both ends of the power-off line are not grounded, the maximum induced voltage after both ends are grounded is in the range of 114V-195V, and the maximum induced current peak value in the circuit is in the range of 0.57A-1.5A when some circuits of the same tower four-circuit line are powered off and overhauled. The research results of this paper can provide technical support for the safe maintenance of 750kV four-circuit lines on the same tower.