During the process of the on-site commission and maintenance of GW4 disconnector unperfected in earlier time

the following phenomena happen sometimes: The left and right contacts couldn’t be properly engaged;operating torque was large;there was unilateral compression on contact finger after closing;conducting arms on the left and right sides were not parallel after opening.On the basis of path-analysis on opening and closing circuit of GW4 disconnector

this paper reveals the relationship between these phenomena and the distribution proportion of the following parts: the length and initial angle of active crank and passive crank

the length of cross bar linkage

and the length of left and right conducting arm

and proposes the optimized initial angle of transmission crank

the length for fixing the cross bar linkage

and the optimization improvements for reasonable distribution of the length of left and right conducting arm.