Measurement of Saturated Water Absorption of the Contamination Layer Deposited on Insulator Surface

Pollution accumulation and the wetting of the contamination layer subsequently formed on the insulator surface are two important factors influencing the pollution flashover of the insulators. To investigate the wetting of contamination layer on the insulator surface, the saturated water absorption of contamination layer on glass specimens was measured in a fog room and the experimental results were analyzed. Under saturated moisture condition, there is a fixed ratio of conductive particles to water molecules in the salt fog that is generated by an ultrasonic humidifier. When the salt fog particles were deposited on the specimens, the surface conductivity of the contamination layer will increase linearly with the salt fog mass deposited. In this paper, a new method was proposed to measure the saturated water absorption of the contamination layer based on the surface conductivity. Based on this method, the influence of non-soluble deposit density (NSDD) and the inclination angle of specimen on the saturated water absorption of the contamination layers were analyzed. The experimental results showed that the saturated water absorption of contamination layer gradually decreased with the increase of inclination angle. With the same NSDD, the saturated water absorption of the contamination layer at the bottom surface of the specimen was less than that of the top surface. The increase of NSDD would lead to an increase of saturated water absorption of the contamination layer under vertical arrangement.