Study On Non-uniformity Pollution Characteristics And It’s Influence On AC Flashover Voltage Of Insulators In Chongqing Area

With the rapid growth of social productivity and national economy,China’s environmental situation is worrying,especially the environment has suffered unprecedented pollution.In order to reduce the impact of air pollution on the city center,under the call of the government,heavy pollution factories have been relocated from the city center to the suburbs.As a result,a large number of small and medium-sized enterprises with coal-fired as the main energy source have been born,and the influence range of industrial pollution has been rapidly expanded by raising the height of chimney.Air pollution will pose a huge threat to the safe and stable operation of local power grid for a long time.Even though the relevant departments have invested a lot of manpower,material and financial resources to study the flashover mechanism and pollution prevention measures,pollution related flashover accidents still occur in recent years.Such accidents not only occur in developed heavy industrial cities and eastern coastal areas,but also occur in remote rural areas and inland underdeveloped areas,with high frequency and serious losses.In this paper,the insulator in Chongqing area is taken as the research object to study the pollution accumulation characteristics and the influence of pollution unevenness on flashover voltage.The main research work is as follows(1)Firstly,the natural pollution test of transmission lines in Chongqing area was carried out.Then the pollution unevenness on such as the upper and lower surfaces,windward and leeward of transmission line insulators were analyzed.(2)In this paper,the artificial pollution tests of 7 standard suspension porcelain insulators under three kinds of non-uniform pollution are carried out in the artificial fog chamber,and the effects of different salt density,different distribution of uneven pollution and uneven pollution degree on AC flashover characteristics of insulator strings are studied.(3)According to the research results of different distribution of uneven pollution and the influence of pollution non-uniformity degree on AC flashover characteristics of insulator string,the pollution flashover voltage under different pollution unevenness(upper and lower surface,sector and torus)is modified according to the empirical formula to obtain the pollution flashover voltage calculation formula under the pollution unevenness degree.On this basis,the selection of external insulation under the condition of non-uniformity of pollution is further calculated to obtain the number of insulator pieces under different non-uniformity.The research results of this paper have very important engineering practical value for the selection,design and maintenance of high voltage transmission line external insulation.