Transient voltage characteristics of power cables in a full-scale wind turbine: Effect of grounding configurations and shielding method of power cables

Lightning strikes on wind turbines can generate high transient voltages that endanger control systems, potentially causing severe damage to sensitive equipment. Effective lightning protection is therefore critical. Using an experimental approach, this study investigates the transient voltages on the power cables of a 5-kW wind turbine subjected by direct lightning strikes. Measurements of voltages on the three-phase cables at the wind turbine tower base and in the control room were conducted under varying conditions, including different loading and grounding configurations. The findings show that connecting a load reduces terminal voltage but increases entrance voltage on the cables, and that grounding the cable shielding layer significantly mitigates voltage magnitudes, reducing them by approximately 50 % in most cases. Furthermore, the impact of supplementing the turbine's individual grounding system with an external grounding grid is assessed, and this approach is found to lower ground potential rise, further reducing cable voltages by up to 50 %. Results here offer valuable insights into enhancing lightning protection strategies for wind turbine power generation systems.