特高压倒V型串杆塔间隙放电特性及绝缘配置分析

Air-gaps Flashover Characteristics and Insulation Coordination of Inverse V-type Insulator String Tower for UHV AC Transmission Line

为得到特高压同塔双回线路新型倒V串杆塔间隙绝缘配置,建立了特高压双回倒V串全尺寸试验塔头,开展了倒V串高压电极对杆塔构架不同间隙距离下的放电特性试验研究,获得了工频电压、1 000μs长波前冲击电压和雷电冲击全电压类型放电特性曲线。结果表明对于3种电压类型,下相间隙50%放电电压梯度均高于中相间隙,其中,下相间隙1 000μs波前操作冲击放电电压梯度较中相间隙高4.6%。结合特高压交流系统电压特点,提出了海拔1 000 m条件下特高压同塔双回线路倒V串间隙配置推荐值,工频电压控制间隙取2.9 m,操作过电压控制间隙取6.5 m,平原和山区雷电防护间隙分别取6.7 m、7.2 m。

In order to get a configuration of inverse V-type insulator tower air-gaps of double-circuit UHV AC power transmission lines, we experimentally investigated different distance air-gaps from high-voltage electrode to tower frame flashover of inverse V-type insulator, Meanwhile, we obtained the flashover characteristics curves of power frequency voltage, 1 000 μs long wave-front switching impulse voltage, and lightning impulse of UHV AC double-circuit tower. Results show that the 50% flashover voltage gradient of bottom phase air-gaps is higher than that of middle phase. The 50% flashover voltage gradient of 1 000 μs wave-front switching impulse of bottom phase air-gaps is 4.6% higher than that of the middle phase. Based on the test results and the characteristics of operating voltage and over-voltage of UHV AC power transmission system, the UHV AC double-circuit tower inverse V-type insulator air-gaps configuration is proposed. The air-gaps configuration of power frequency voltage and switching overvoltage are 2.9 m and 6.5 m, and the lightning protection air-gaps are 6.7 m and 7.2 m in mountains and plains, respectively.