随桥电缆交叉互联护套接地电流影响因素分析

Influence Factors of Induced Current under Cross-Bonded Mode of Cables Laid along Bridge

交叉互联接地方式可以降低电缆两端直接接地点之间的感应电压差,抑制金属护层的感应电流,从而成为电缆线路主要的接地方式之一。本工作通过建立随桥电缆交叉互联段的计算模型,计算不同情况下的接地电流,研究交叉互联段各单元段长度、接地电阻、负荷,以及两端是否采用同一接地点对接地电流的影响。计算结果表明,交叉互联段两端是否采用同一接地点对接地电流的不平衡度最大。因此,建议实际工程中在尽量保证交叉互联各单元段长度差异较小的前提下,尽可能让交叉互联段两端采用不同的接地系统进行接地,以降低接地电流幅值和不平衡度。

Cross-bonded grounding can reduce the induced voltage difference between the direct grounding points at both ends,inhibit the induced current of the metal sheath,and thus become one of the main grounding methods for cable lines.By establishing the model of the cross-bonded section of the cable,the grounding current under different conditions was solved,and the influence of the length of each unit of the cross-bonded section,grounding resistance,load and whether the same ground point was used at both ends on the grounding current was studied.The results show that whether the same ground point was used at both ends of the crossover interconnect section had the greatest imbalance of the ground current.Therefore,it is suggested that different grounding systems should be adopted at both ends of the cross-bonded section as far as possible to reduce the amplitude and imbalance of grounding current under the premise of ensuring that the length of each unit section is close in the actual project.