Study and protection of lightning overvoltage on DC cables of solar power generation

In this paper, lightning induced overvoltage on DC cables of solar power panel, which was laid on the ground and an underground level with proper insulation thickness, was investigated when a lightning strike at a nearby place and its proper protection scheme was verified. The result shows that on ground cable voltage is approximately 28.83% more than that of the underground cable having soil resistivity 100Ω-m. Moreover, when soil resistivity increases to 1000Ω-m then the underground cable voltage is less about 48.50% than that of the on ground cable. The induced voltage caused by lightning electromagnetic interference on DC cables of solar power system at power conditioning subsystem (PCS) is analysed using electromagnetic field analysis approach. The FDTD method was applied to calculate induced voltage. Virtual Surge Test Lab (VSTL) is used for FDTD calculations, which solve Maxwell´s electromagnetic equations with least approximations. The model of solar power system was represented with thin wires.