Abnormal heating phenomenon of composite insulator occurs frequently in operation

of which the main reason is aging and surface contamination. In this paper

the simulation model of composite insulator under such four typical conditions as normal operation

humid and hot aging

partial and overall contamination is set up respectively by the use of FEM multi-physical field simulation in combination with the measured material parameters. Such two kinds of models as electrostatic and current fields are set up respectively in accordance with the different heating characteristics of humid and hot aging as well as surface contamination. It is found through electric field calculation that the electric field along the surface of the composite insulator after humid and hot aging increases and that the interface electric field decreases. The electric field of partial contaminated composite insulator at the contamination point decreases slightly and the electric field distortion of the overall contaminated composite insulator due to increase of current of the surface is serious. It is found by comparing the electrothermal joint simulation and test result of coupling thermal field with dielectric loss as interface and current field filed-thermal field coupling that the normal and partial contaminated composite insulator has basically no temperature rise;while the temperature rise of the composite insulator with humid and hot aging and overall contamination is obvious but the the temperature gradient direction is opposite. It is concluded through the simulation calculation that the position of maximum temperature rise and the test result are identical and the test result and the simulation calculation result are basically in agreement.