1000kV/500kV同塔混压四回输电线路反击耐雷性能

在线路走廊比较紧张的东部地区,特高压电网考虑架设同塔混压多回输电线路,开展特高压同塔混压线路反击耐雷性能研究具有重要的意义。采用统计法计同时考虑工作电压的影响,在电磁暂态程序(PSCAD/EMT-DC)中建立了1000kV/500kV同塔混压四回输电线路反击耐雷性能仿真模型。和常规线路对比,得出了特高压同塔混压线路反击耐雷性能的特点。针对其特点,分析了500kV上层横担外侧导线和一侧导线绝缘水平及500kV相序排列对线路反击耐雷性能的影响。结果表明:随着外侧导线绝缘水平的增强,500kV线路的单、双回反击跳闸率降低;随着横担一侧导线绝缘水平的增强,500kV线路的双回反击跳闸率降低;当外侧导线为异名相导线时,500kV线路的单回反击跳闸率较高,双回反击跳闸率较低。为了改善500kV线路的反击耐雷性能,可以增强外侧导线的绝缘水平,为了改善500kV线路的双回反击耐雷性能,可以增强横担一侧导线的绝缘水平,采用不平衡绝缘,外侧导线应采用异名相导线。

Lightning Protection Performance of Back-flashover for Quadruple-circuit Transmission Line with Dual Voltage 1000 kV/500 kV on the Same Tower

Mixed-voltage multi-circuit transmission line on the same tower can be considered in UHV grid in eastern China where the area for the line corridor is limited.It is of great significance to study the back flashover performance of the UHV mixed-voltage multi-circuit transmission lines on the same tower(UMMTL).Consequently,taking the influence of the working voltage into account by using statistical method,basing on PSCAD/EMTDC,we established a simulation model of the back-flashover performance for quadruple-circuit transmission line with dual voltage 1000 kV/500 kV on the same tower.Compared with the conventional lines,characteristics of the back-flashover performance were summarized for UMMTL.With the consideration for the specific characteristics,the influences of the insulation level of the lateral conductor,one side conductor of the 500 kV upper layer cross-arm and the phase arrangement for 500 kV lines on the back-flashover performance were analyzed.The results show that the back-flashover trip-out rate of the single circuit and the double-circuit for 500 kV lines both decrease when the insulation level of the lateral conductor is enhanced.The back-flashover trip-out rate of the double-circuit for 500 kV lines decreases when the insulation level of the one side conductor of cross-arm is improved.The back-flashover trip-out rate of the single circuit for 500 kV lines is comparatively higher than that of the double-circuit when different phase conductors are used for lateral conductor.Thus the back-flashover performance for 500 kV lines can be improved by enhancing the insulation level of the lateral conductor.The back-flashover performance for 500 kV double-circuit lines can be improved by enhancing the insulation level of one side conductor for upper layer cross-arm,and with the implement of unbalanced insulation as well as different phase conductors for the lateral conductor of 500 kV lines.