Study On The Influence Of Unconventional Pollution In Guangdong Area On Discharge And Pollution Flashover Of Outdoor Insulation

In this paper, the pollution composition analysis was presented to study the effect of unconventional pollution compositions on outdoor insulation discharge and flashover performance, which was based on the current use of ESDD and NSDD to characterize the pollution level of high voltage insulators, and suppression measures were put forward respectively according to the abnormal discharge and pollution flashover such as discharge in sunny weather and pollution flashover in clean regions in Guangdong area.As the present analysis system of pollution composition on insulators is not yet established completely at home and abroad, a methodology research of analyzing the composition was developed based on the pollution on the surface of insulators. By analyzing the pollution characteristics of insulators and synthesizing the analysis of screening various chemical compositions, a study on technologies and methods on analysis of pollution composition was carried out, and a complete set of process of analysis of pollution composition was proposed. While the routine measurement of ESDD and NSDD, the analysis of pollution composition was performed simultaneously to supply the current characterization method of the pollution level of insulators, and it could also be referred for the pre-design, construction, operation and maintenance of outdoor insulation.In this paper, the ESDD and NSDD measurement and the pollution composition analysis were performed in terms of the unconventional discharge accident in 500 kV Gangcheng substation, and the local climate, environment and soil properties were considered. The unconventional pollution compositions were identified as aluminum phosphate and glucose, which were used in artificial pollution test to carry out discharge and pollution flashover test on a piece of insulator. The unconventional discharge could be reproduced and the analysis of pollution composition was verified. The unconventional discharge was explained and the effect was studied of pollution containing glucose and aluminum phosphate on corona inception voltage and flashover voltage of insulators.It was analyzed in this paper that hygroscopicity was the common characteristic of the aluminum phosphate and glucose, and then it was studied that the effect of different kinds of hygroscopic pollution on outdoor insulation discharge and pollution flashover characteristic based on plane plate model experiment. At the same time, it was recorded the discharge and flashover with a high-speed camera. It was testified that hygroscopic pollution could reduce the pollution flashover voltage at lower humidity; while its effect on reducing the pollution flashover voltage becomes weaker if the humidity was higher; and in saturation humidity pollution with different hygroscopicity had no effect on pollution flashover voltage, but if the humidity was higher, the amount of hygroscopic pollution was larger and its hygroscopicity was stronger, the discharge became more serious, the flashover arc was stronger, and the arc levitation was more violent. The analysis showed that it may be related to the mutual aggravation of the discharge and arc with the ionization of the water molecules and the ionization of the air.