Experiments and analysis of sand dust flashover of the flat plate model

The influence of sand dust on the electrical discharge characteristics of outdoor insulation has drawn worldwide attention. Based on tests on the typical flat plate model, this paper presents research on the flashover characteristics of outdoor insulation in sand dust environment under ac and dc voltages, by means of which the effects of wind velocity, charge of sand particles, sand deposit on insulator and moisture content of sand particles on the flashover process are obtained. The test environment of the flat plate model is classified into sand-wind and sand deposit environments. In the sand-wind environment, wind velocity has remarkable influence on the ac and dc flashover voltages of the flat plate model while the sand and the charge of sand particles have little influence. In the sand deposit environment, the ac and dc flashover voltages of the flat plate model are influenced by the sand deposition density and the moisture content of sand particles. Moreover, according to the record of the flashover process and the calculation of the change of the electric field distribution during this process, the flashover mechanism is analyzed, which shows that the region without sand and the leakage current play important roles in the flashover of the flat plate model in the sand dust environment.