Effects of potential difference within large grounding grid on secondary cables due to lightning strike

When substations suffer from lightning, the potential difference occurs within the grounding grid, which will generate induced voltage between the core, shield and the armor of the two-end grounded cables and significantly affect the secondary system in substation. This paper analyses the potential difference within large grounding grid and its influence on the secondary cables through the field test. The induced voltage in cable was measured and analyzed. The usage of drain wires was studied.