A research team in Indonesia has proposed a novel grounding strategy to mitigate lightning-induced overvoltage in PV systems by identifying optimal grounding-point locations and evaluating different grounding configurations.

“Previous research has generally protected solar panels using a Lightning Protection System (LPS) with lightning rods connected to down conductors, such as Franklin rods,” the scientists emphasized. “This study considers the possibility of direct lightning strikes on solar panels or their supports, even if an LPS is installed. This occurrence allows current to flow through the solar panels to the grounding point.”

The researchers developed an equivalent electrical circuit model to investigate the transient overvoltage response of PV systems to lightning strikes. The simulated array comprised ten solar panels, each rated at 200 W, representing a section of a larger PV installation. Using ATPDraw 7.2 software, they modeled the electrical characteristics of the PV frames, mounting structures, grounding conductors, and electrodes through equivalent resistance, inductance, capacitance, and mutual inductance parameters.

Lightning strikes were simulated using a Heidler current source with a peak amplitude of 50 kA and an impulse waveform of 1.2/50 μs. Two configurations were investigated: direct grounding through the PV module frames and grounding through the mounting structures. The simulations assessed the effects of soil resistivity, grounding-point location, and the number of grounding connections on transient voltage distribution.

The researchers varied grounding-point locations to determine how the electrical path between the lightning strike location and the grounding connection influences overvoltage levels. They also compared single- and dual-grounding arrangements to assess the benefits of additional connections.

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