排列方式对降低电缆金属护层感应电压的影响分析

Effect of Arrangement Modes on Reducing the Induced Voltage of Cable Metal Sheath

在进出变电站线路段,双回单芯电缆同沟敷设的情况普遍存在,在雷电冲击电压或系统发生工频短路故障时,电缆金属护层上会产生感应过电压,降低电缆寿命。比较平行排列、“品”字形排列和自主设计的集中平衡排列方式下电缆金属护层的感应电压,发现平行排列方式极易发生环流,导致线路停电;“品”字形排列方式使得三相金属护层的感应电压达到较为理想的平衡效果,但仍存在回路电压;集中平衡排列方式能有效降低电缆金属护层的感应电压,降低接地事故发生率,延长电缆使用寿命。

In the circuit section in and out of the substation,the double-return single-core cable laying in the same trench is common.In case of lightning impulse voltage or power frequency short-circuit fault in the system,the cable metal sheath will generate induced overvoltage and reduce the cable life.By comparing the induced voltage of the cable metal sheath in parallel arrangement,“Pin”arrangement and self-designed centralized and balanced arrangement,it is found that the parallel arrangement is easy to cause circulation and lead to power failure.The induction voltage of the three phase metal sheath can reach the ideal balance effect,but there is still loop voltage.The centralized and balanced arrangement can effectively reduce the induced voltage of the cable metal sheath,reduce the incidence of grounding accidents and extend the service life of the cable.