1000 kV特高压系统的不断发展对输电线路操作过电压允许值提出了更高的要求.如何限制特高压输电线路的操作过电压倍数已成为发展特高压电网所要解决的技术难点.选相投切技术是解决这一难点的重要技术,而相控技术目前发展的瓶颈是对断路器预击穿和机械分散性问题研究的不足.该文结合特高压双断口断路器不同开距下电场强度动态变化过程,计算出合闸预击穿时间,再利用 ATP-EMTP 软件对1000 kV 输电线路进行合理建模以及合闸和重合闸的电磁暂态仿真.仿真结果表明选相投切结合避雷器可有效地抑制操作过电压.操作过电压的降低能够减少线路杆塔空气间隙,进而可以缩减特高压电网投资成本.%The continuous development of the 1 000 kV UHV system puts forward higher requirements to the allowable value of the switching overvoltage for the transmission line. How to restrict the operation overvoltage multiple of transmission lines had already been a crucial question to be solved for the development of ultra-high voltage grid. The controlled switching technology is an important technology to solve this difficult point. However the development bottleneck of this technology is currently the study of pre-breakdown and mechanical dispersion for the circuit breaker. The dielectric recovery characteristic curve was obtained through the electric field strength distribution of arc extinguish chambers under different opening distance in this paper. The closing and reclosing model of 1000kv transmission lines were built in electro-magnetic transient program ATP-EMTP. The simulation results show that the amplitude of operation overvoltage can be effectively suppressed by controlled switching and MOV. Therefore decreasing switching overvoltage plays an important role in reducing the air gap of the tower, which can lessen the investment cost of ultra-high voltage grid.
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