The Influence of Uneven Pollution Distribution on the Electrical and Thermal Characteristics of Insulators

Abstract

To study the temperature variation of DC insulator string under uneven pollution degrees, a 70kV DC double-enveloped porcelain insulator string model was established. The electrical and thermal field of the insulator string was simulated by the finite element method, and the influence of uneven pollution conditions was analyzed. The results show that under the condition of uniform saturated wet pollution, the temperature of insulators increases with different amplitude, The overall temperature of the insulator increases as the total pollution degree increases. In addition, it is found that wet pollution tends to flatten the potential distribution near the high-voltage electrode, and the effect is more obvious when the potential distribution is uniform and the pollution is uniform. When the salt density on the upper and lower surfaces of an insulator is inconsistent, the pollution on the lower surface of an insulator has a greater impact on the temperature rise of the insulator string than that on the lower surface. As the contamination on the bottom surface of the insulator increases, the whole temperature of the insulator string increases. When the salt density ratio on the upper and lower surfaces changes from 7:1 to 1:7, The insulator string temperature rises first and then drops, reaching a maximum temperature of 1: