Study On AC Flashover Performance And Process Of Long Iced Insulator Strings

The severe atmospheric environment of low atmospheric pressure at high altitude with pollution and icing has an important effect on the external insulation performance of transmission lines and threatens the reliability of a power system. Therefore, a systematic study on flashover performance of several types of long insulator strings at the severe atmospheric environment has both important academic meaning and engineering value. Based on a great of laboratory investigation carried out on the AC flashover performance of several types of long insulator strings in the great multi-function artificial climate chamber of ChongQing University, this paper studies systematically the AC outer insulate performance of several type of long iced insulator strings and made the theoretic analyses in detail.This paper made the experiment investigation as following: ㏕he experiment investigation on influence of icing status and external insulation of long insulator strings icing with HV and without HV. (2) The experiment investigation on AC flashover performance of icing insulator strings with pollution at high altitude (0~ 4000m) and the number of insulator. (3)Analyzed the flashover process of iced insulator strings by high-speed camera.Based on the experiment result, The conclusion of this paper can be put forward as following: (1)There are obvious different influence in the density of ice and external insulation icing with and without HV. The density of ice on insulator icing with HV is lower than icing without HV, the flashover and withstand voltage of iced insulator strings icing with HV is higher than the iced insulator strings icing without HV, and on the icing with HV condition the insulator in high voltage port of iced insulator string can't be abridged in icing process. (2)The low air pressure and the number of insulator strings have influence in flashover voltage. It was put forward a calculation expression for correcting the minimum AC flashover voltage of insulators of XP-70, XWTVTO and FXBWVl 10/100 in condition of high altitude. And got the linear relation between flashover voltage and the number of insulator. (3)According to the result of the potential distributing of iced insulator strings, observation and photograph of flashover process and variety of leakage current in flashover process, The main discharge process of porcelain insulator strings start from high voltage port to low voltage port, but the main discharge process FXBWVl 10/100 start from low voltage port to high voltageport.