±1100kV干式平波电抗器电场分布和操作冲击放电特性

Study on Electric Field Distribution and Switching Impulse Discharge Characteristics of ±1100kV Dry-Type Smoothing Reactor

±1100 kV干式平波电抗器是特高压直流输电工程中关键主设备之一,为确定平波电抗器的外绝缘特性,开展了±1100 kV干式平波电抗器电场和操作冲击放电特性研究。首先,对±1100 kV平波电抗器的电场分布进行了仿真计算,在直流电压下,平波电抗器电位分布较为均匀,关键位置电场强度值均低于一般要求的1500 V/mm的经验值;然后,开展了干燥及模拟人工降雨下±1100 kV平波电抗器操作冲击放电试验,得到了其在安装不同管径均压环时的50%操作冲击放电电压U50%:随着均压环管径的增大U50%略微升高3.06%;随着雨量的增大,U50%呈降低趋势,大暴雨条件下的U50%较干燥情况下U50%相比降低4.7%;不同试验条件下±1100 kV平波电抗器的U50%均大于工程所需的2400 kV。由仿真与试验结果可得,±1100 kV平波电抗器设计能够满足工程的需要,同时研究结果为±1100 kV平波电抗器外绝缘参数的确定提供了参考。

±1100 kV smoothing reactor is one of the main devices of UHVDC transmission projects.To determine external insulation characteristics of the reactor under wet weather condition,electric field distribution and switching impulse discharge characteristics of ±1100 kV dry-type smoothing reactor were studied in this paper.Firstly,electric field distribution of the reactor was simulated.It was found out that potential distribution of the reactor was quite uniform under DC voltage with electric field intensity lower than 1500 V/mm（empirical value）.Then,impulse discharge tests of the reactor were carried out under dry and artificial rain conditions and 50% switching impulse discharge voltage were obtained.Its U50% was slightly risen（by 3.06%） with increase of diameter of grading ring.U50% showed a downward trend with increase of rainfall and decreased by 4.7% under heavy rain condition compared to that under dry condition.U50% in different test conditions are all higher than 2400 kV,the maximum voltage required by relevant specification.Based on simulation and test results,design of the reactor meet actual needs of project,and the results can provide a reference for determining external insulation parameters of ±1100 kV smoothing reactor.