不同海拔下电晕笼分裂导线起晕电压的计算分析

为了研究海拔高度对电晕笼分裂导线起始电晕电压特性的影响,建立电晕笼钢芯铝绞线起始电晕电压的计算模型,并开展相应试验研究。采用模拟电荷法计算钢芯铝绞线的空间电场强度。依据极不均匀电场下自持放电判据,建立不同海拔高度电晕笼分裂导线电晕起始电压的计算模型。在超/特高压人工环境气候试验室内,以500 m海拔高度为间隔,系统开展19~4-000-m海拔高度范围内六分裂导线起始电晕电压的试验研究。试验获得超高压电晕笼不同海拔高度下6-LGJ—400/50、6-LGJ—500/45分裂导线的起晕电压。计算获得不同海拔高度、分裂间距、导线分裂数及绞线表面粗糙系数下的导线起晕电压曲线族,以及不同绞线半径及最外层铝绞线股数的表面粗糙系数计算结果。分析结果表明:计算模型能够较好地计算电晕笼内绞线的起晕电压;在350~500-mm分裂间距范围内,分裂导线起晕电压随着分裂间距的增大而降低,随着导线分裂数的增加而升高;绞线表面粗糙系数与绞线最外层铝线半径与绞线半径之比相关。

Calculation and Analysis on Corona Onset Voltage of Corona Cage Bundle Conductors at Different Altitudes

In order to research the effect of altitude on corona onset voltage of corona cage bundle conductors,a calculation model for corona onset voltage of corona cage stranded conductors was established,and corresponding tests were performed.A charge simulation method was adopted to calculate the space electric field strength of the stranded conductor.According to self-sustained discharge criterion in severe Non-uniform electric field,a calculation model for corona onset voltage of corona cage bundle conductors at different altitudes was established.At the EHV/UHV artificial climate laboratory,corona onset voltages of six-bundle conductors were tested systematically at 19~4 000 m altitude range with 500 m interval.Corona onset voltages of corona cage bundle conductors 6 LGJ-400/50,and 6 LGJ-500/45 were obtained.Conductor corona onset voltage curves at different altitudes,bundle spacing,bundle numbers and surface roughening coefficient were obtained,and surface roughening coefficient calculation results at different stranded radius and numbers of outmost alum wires were obtained.Analysis results show that the calculation model can effectively calculate the corona onset voltage of a stranded conductor in a corona cage;with 350~500 mm bundle spacing range,a bundle conductor’s corona onset voltage decreases as the bundle spacing increases,and increases as the bundle number increases;the stranded conductor surface roughening coefficient is related to the ratio of a stranded conductor’s outermost aluminum wire radius and the stranded conductor’s radius.