特高压换流站空气间隙放电特性的海拔修正比较研究

高压输电系统采用长空气间隙绝缘,其破坏性放电电压不仅与所加电压的波形相关,还与大气条件相关.本文采用G参数法研究中国蒙古高原、云贵高原地区直流800kV和交流500kV、1000 kV输电系统空气间隙的高海拔修正.研究统计了设计所在地近10年逐年逐月气象数据,计算了操作冲击以及雷电冲击电压作用下的不同修正系数,并将这些数据与IEC 60071中海拔修正的相关规定进行了比较.经分析认为,IEC60071采用的海拔修正适用于高湿度低纬度气候条件,中国高原地区的大气条件差异较大,应依据当地气象条件确定修正系数.中国正在筹建的800kV级直流特高压换流站在国际上还没有先例,其空气间隙设计中应考虑中国区域性气象条件.

Altitude Correction for Breakdown Voltages of Air Clearance in UHV Converter Stations

Long air-gaps are used in high-voltage transmission systems whose discharge voltages depend on not only the waveforms of applied voltages, but also the atmospheric conditions. This paper researches altitude correction for long air-gaps of AC500kV, 1000kV and DC800kV substations in Mongolia and Yungui Plateau in China with method of G parameter. Based on the atmospheric data collected monthly for last 10 years, correction coefficients are calculated for the lightning and switching impulses, which are compared with those from IEC60071 standards. It is shown that the correlated research conclusions of IEC60071 standards are appropriate for damp regions, and because of the special atmospheric conditions in plateau regions of China, the correction coefficient is different for Mongolia and Yungui Plateau, which should be determined locally. As the 800kV DC ultra-high voltage (UHV) transmission lines and converter stations being built under way in China have no precedent in the world, their air clearance must consider the local atmospheric conditions.