PROJECT TITLE :

Investigation of DC discharge behavior of polluted porcelain post insulator in artificial rain

ABSTRACT:

The surface discharge of natural polluted post insulators in rain is an important factor which affects the external insulation of HVDC converter stations. With the unreal contamination flashover tests in rain for porcelain post insulators, this paper has obtained the flashover method and discharge characteristics of the check samples below artificial rain condition. It has been observed that the discharge of water droplet on the shed edge plays a very important role in the entire method of pollution flashover in rain. When a water droplet hangs on the shed edge, the maximum electric field strength seems within the vicinity of vertices, instead of the lateral space of the water droplet. Therefore, the streamer propagates solely within the direction of the air gap between sheds. Moreover, the influence of raining conditions including intensity and conductivity on the flashover voltage has been investigated. Check phenomena additionally indicate that because of the various damp and dry band conditions, surface discharge characteristics of post insulator in rain are totally different with that in fog, that cause totally different flashover voltages. This study provides a new understanding for the HVDC insulator pollution flashover in wet atmosphere.