750kV同塔双回输电线路空气间隙放电特性研究

Research on Air-gap Discharge Characteristics of 750kV One Tower Double-circuit Transmission Line

为取得我国750 kV同塔双回输电线路的设计依据,结合我国西北电网公司即将建设的750 kV同塔双回输变电线路工程,试验研究了750 kV同塔双回线路真型塔空气间隙操作冲击（含长波前时间）、雷电冲击和工频电压。采用升降法获得了3～7 m距离的杆塔空气间隙操作冲击、雷电冲击放电特性曲线,采用闪络法获得了1～4 m距离杆塔空气间隙的工频放电特性曲线;研究了不同杆塔宽度对放电电压的影响。试验表明,操作冲击和工频放电电压随着杆塔宽度的增大而降低。通过分析提出了不同海拔高度750 kV同塔双回线路相地最小绝缘间隙推荐值,该结果接近IEC等国外类似试验,证明了其可比性和可靠性。

In accordance with the project of 750 kV one-tower double-circuit transmission line to be constructed soon by Northwest China Grid Company Limited, the switching impulse （including long front time switching impulse）, lightning impulse and power frequency of 750 kV one -tower double-circuit transmission line were experimentally investigated. An up-and-down test was applied to obtain the switching impulse and lighting impulse characteristic curve of air gap at the distance of 3- 7 m. A flash-over test was applied to obtain the power frequency characteristic curve of air gap at the distance of 1-4 m. The discharge characteristics of different tower width show that the discharge voltage values of switching impulse and power frequency are reduced by the tower width increased. And the recommended minimum phase-ground insulation-gap values of 750 kV one-tower double-circuit transmission line at different altitudes are analyzed. The test results are closed to those from similar experiments of IEC, showing the reliability and comparability of this test.