Research of Electric Field Distribution in 500 kV Overhead Transmission Linewith Four Circuits on One Tower

The overhead transmission line with four circuits on one tower can full save and make reasonable use of the limited routeway resourse. This article presents calculation methods of electric field intensity near the line with four circuits on one tower of 500 kV and 500 kV/220 kV mixed voltage and compares the result that of the traditional 500 kV single circuit and double circuits on one tower,and tries to find out the best lay form of wires between phases and the least distance to the ground,and analyzes the influence of the phase angle of voltage between wires, and also analyzes the influence when one circuit quits for examine and repair or the malfunction.