The complex structure of fixed clamping contact of the 550 kV high-voltage disconnector leads to serious corona. For understanding the electric field distribution around the contact surfaces and putting forward optimization proposals

the 3-D electric field distribution of the model without grading ring was calculated in this study

and the result showed that the strand wire circles

the lower clamp and the heads of static contact rod are the areas where electric field intensity is higher. In consequence

two anticorona contact structures were proposed

in which a small disc-type grading ring and a double large grading ring were installed to each of four clamps

respectively. And the two structures were compared via simulation. The simulation revealed that the small disc-type grading ring with different geometrical parameters exerts little effect on corona on surface of the strand wire circles

and its shielding effect is limited

while the structure with double grading rings has a larger shielding area and better shielding effect. Radio interference test of a GW16A-550 high-voltage disconnector with double grading rings on its contact was completed

the results show that the structure of the fixed contact with double grading rings is better than the other at 550 kV voltage level. This study may provide a theoretical reference for anticorona structure design of fixed contact of high-voltage disconnector.