Lightning Induced Coupling Performance of Secondary Cables in Substation with Different Terminal Load and Surge Injection Position

During lightning strike on a power substation grounding facility, surge currents flow into the substation's grounding system, where inducing coupling effects in the secondary cables happens. There is currently limited research on the influence of cable terminal load and grounding-grid dispersion paths on the induced coupling of secondary cables. In this paper, the effects of four terminal load modes and two grounding grid dispersion methods on cable port voltage are investigated using both time-domain and frequency-domain methods. The results show that the core induced voltage amplitude is highest when the cable is grounded only at the far end through the load, reaching twice as much as when the cable is grounded at both end. The dispersion of ground grid current pathway significantly impacts cable-induced voltages in both time and frequency domain, particularly in scenarios involving near-ended grounding by load and double-ended ungrounding. Following the transition of the grounding grid dispersal method from the right side to the central extended grounding body injection, there is an overall reduction of approximately 10-30% in the f
-3dB
. Buried cables are more susceptible to variations in the dispersion path of the grounding grid compared to ground cables.