Flashover characteristics of flat model under DC voltage in wind-sand two-phase mixture

The influence of sand dust on discharge of outdoor insulation has caused widespread concern. At present, the research results show wind-sand electricity has have a remarkable effect on the discharge characteristics of insulator and has little influence on the discharge characteristics of air gap. The flashover of insulator strings is discharge along the insulator surface and air gaps, and the sand dust deposited on the insulator surface may affect the flashover characteristics of insulator strings. This paper studies flashover characteristics of flat model under DC voltage in wind-sand two-phase mixture. The experimental results show that under positive polarity voltage the flashover voltage of flat model has a maximum value while under negative polarity voltage the flashover voltage has a minimum value with a certain degree of sand dust deposition. The wind or sand under sand-dust weather has an important effect on the discharge characteristics of flat model. In certain variation range of electric charge, electric charge of sand dust has little effect on the flashover voltage of flat model under direct voltage. The deposition of sand has significant influence on the flashover process of flat model, and the extent is related to the deposition density and moisture content of sand particle. The moistened sand can be considered as a special kind of contamination.