Influence of flow-electric field on withstand characteristics of HV suspension insulators in sandstorm circumstance

Long range transmission lines in north-west China are inevitably set up across sandstorm-prone areas. Pollution deposition of insulators working under such rigorous environment is nonuniform due to the influences of flow field and electric field, thus withstand characteristics obtained in traditional artificial pollution test might not be accurate enough. In this paper, sandstorm simulation experiments were carried out to simulate the actual working conditions, and a comparison was made between the withstand characteristics obtained in simulation experiments and artificial pollution tests. The results show that the withstand voltages of insulators went through sandstorm simulation experiment decreased significantly comparing to those prepared by quantitative Brushing Method, which applies the pollution layer uniformly on the insulator surface. Moreover, the withstand voltages of each shed on the insulator string are different at different position and various wind speeds, which reflect the influence of electric field and flow field. In addition, the mechanisms of the influences of flow field and electric field on withstand characteristics of insulators were discussed.