高海拔特高压并联绝缘子的直流污闪特性

DC Pollution Flashover Performance of Ultra High Voltage Parallel Double Insulators in High Altitude Area

为给已建成的±800kV特高压直流输电线路提供运行维护指导,并为拟建设的直流特高压线路的外绝缘设计提供参考,研究了双串并联绝缘子在高海拔特高压条件下的污闪特性。选用大吨位瓷绝缘子XZP-300和1大1中4小复合绝缘子作为试品,重点研究了在实际海拔2 100m条件下的双串并联绝缘子人工污闪试验电压的概率分布特性,分析了双串并联与单串悬挂绝缘子污闪特性的差异,研究了边缘间距对双串并联绝缘子污闪特性的影响。结果表明,在高海拔条件下,采用升降法获得的双串并联悬挂的瓷和复合绝缘子污闪电压值均满足正态分布;当盐密在0.03～0.2mg/cm2范围内时,双串并联瓷绝缘子的单片绝缘子污闪电压范围为19.6～5.8kV,低于单串的20.5～6.9kV;当盐密在0.05～0.2mg/cm2范围内时,双串并联复合绝缘子的单位绝缘子高度污闪电压范围为105.6～38.7kV/m,低于单串的109.9～43.1kV/m,;当边缘间距>20cm时,边缘间距值的变化对双串并联绝缘子污闪电压的影响不显著。

To guide operation and maintenance for established 800 kV ultra-high voltage direct current{ UHVDC） transmission lines, and to provide references for external insulation design of future UHVDC projects, we studied the pollution flashover performance of parallel double insulator strings （ Ⅱ strings} in high-altitude areas. Tests were performed on samples of XZP-300 porcelain insulators and one major, one middle and four minor sheds shaped composite insulators. The probability distribution of flashover voltages under artificial contamination test was explored. Moreover, the difference between flashover voltages of Ⅱ strings and single I strings was analyzed, and the influence of spacing on the flashover voltage of Ⅱ strings was investigated. The results showed that the flashover voltages of Ⅱ strings and Ⅰ strings installed by up-and-down method in high-altitude areas were distributed normally. When the equal salt density varied from 0.03 to 0.2 mg/cm2 , the one-unit flashover voltages of porcelain Ⅱstrings and porcelain single Ⅰ string varied from 19.6 to 5.8 kV and from 20.5 to 6.9 kV, respectively. When the equal salt densities varied from 0.05 to 0.2 mg/cm2 , the per-meter flashover voltage of porcelain Ⅱ strings and porcelain single I string varied from 105.6 to 38.7 kV and from 109.9 kV to 43.1 kV, respectively. When the spacing exceeded 20 cm, further enlarging spacing had no significant effect on the flashover voltage of U strings.