交流1000kV与500kV/220kV同塔4回线路的感应电压和电流

Induced Voltage and Induced Current on AC Same-tower Four-circuit Lines Comprised of Double-circuit 1 000kV Lines and Double-circuit 500kV or 220kV Lines

为给同塔4回架设的双回1000kV与双回500kV或220kV线路选择合适的接地开关参数，计算了这种线路在不同的运行方式、导线相序和同塔架设长度下回路间的感应电压和电流。采用电磁暂态计算程序EMTP程序建立了双回1000kV与双回500kV、220kV同塔4回线路的模型并进行计算。在计算结果的基础上，研究了耦合地线、增大1000kV与500kV或220kV导线层间距和降低杆塔高度等3种措施对限制感应电压和电流的影响。根据计算结果，提出500kV和220kV线路受1000kV线路的感应较大，其感应电压和电流大大超出B类接地开关的开合能力；若1000kV和220kV导线的层间距离增大2m，220kV停运线路的感应电压和电流降低约10％；220kV杆塔加装耦合地线，停运线路的感应电压和电流降低约6．7％～20％；将杆塔高度降低7m，停运线路的感应电压和电流降低约18％。这3种措施的效果不佳，且成本较高，推荐接地开关加装辅助灭弧装置以提高其开合感应电压和电流的能力。

In order to select parameters of earthing switches on AC same-tower four-circuit （ST4C） lines comprised of double-circuit 1 000 kV lines and double-circuit 500 kV or 220 kV （500 kV/220 kV） lines, we calculated the voltage and current on the lines induced between different circuits under different operation modes, different phase sequences and different lengths of the four-circuit lines, and established a model of AC ST4C lines in the electromagnetic transient program EMTP. Using the results, we studied the effects of three measures, i. e. installing coupling ground wires, increasing the distance between the conductors of the 1 000 kV lines and the 500 kV/220 kV lines, and lowering the height of tower, for limiting the induced voltage and current. It is concluded that the 500 kV/220 kV lines are strongly affected by the 1 000 kV lines, and the induced voltage and current are far beyond the ability of B-type earthing switches. However, all the three measures mentioned are considerably costly and ineffective： increasing the distance between the 1 000 kV and 220 kV conductors by 2 m can reduce the induction voltage and current on 220 kV line by about 10% ; adding coupling ground wires to 220 kV tower decreases the induction voltage and current by only 6.7%- 20% ; reducing the height of a tower lower 7 m lowers the induced voltage and current by about 18%. As a result, we suggest installing auxiliary interrupters on the earthing switches to deal with the induced voltage and current on HVAC lines.