Experimental research on interference in secondary cable from short-circuit current in substations

The short-circuit current in a substation may result in not only step voltage and touch voltage on person, but also interference in secondary cable. In this paper, the effect of the short-circuit current on the interference in the secondary cable was investigated by experiment. By making a single-line-to-ground fault in an actual 220/110 kV substation artificially, the transient voltages in various grounded and loaded cables were measured. The effective way to reduce the interference in the secondary cables was discussed. The most useful method is making the grounding grid dense or using grounding conductor with low resistance which can reduce the potential difference on the grounding grid.