Study of the selection of an individual grounding location point against direct lightning strikes on solar panel systems

Abstract

Solar panels are among the most widely used green power generation technologies and play a significant role in the global energy transition. However, their installation in open areas increases the risk of direct lightning strikes. An inadequate grounding system is a critical factor that can lead to severe damage from such events. Therefore, this study focuses on assessing the design consideration of an effective grounding system to mitigate over-voltage in solar panels caused by lightning strikes. Two commonly used PV grounding installations consist of grounding points connected to PV frame and grounding connected to mounting are evaluated. Detail electrical circuit model is developed considering the PV panel frame and PV panel mounting for understanding the effect of lightning strike around the PV farm. The effect of soil resistivity is also evaluated. Moreover, a comparison of single- and double-point grounding is provided. The transient voltage response is used to measure all considered variables. The results show that the transient voltage is increasing with gradient 0.36kV/Ohm when soil resistivity changes from 30Ohm to 3000Ohm. The comparison among the two typical grounding installations results in almost similar values of voltage transient response with the maximum value of transient voltage are 2.64 MV and 2.43MV, minimum transient voltage is 1.96MV and 1.93MV for PV frame grounding point and mounting respectively. The comparison between single and double grounding shows that the transient voltage is decreasing between 45-52% in some cases and points. The analysis on grounding location shows that grounding points located farther from the lightning source produce longer current paths, resulting in higher peak voltage values. Based on this analysis, PV grounding design can be optimized by decreasing grounding resistance and installed multiple points grounding. Therefore, the grounding installment either in PV frame or mounting does not have significant effect on lightning transient voltage response

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