Reduction of PID in Utility-Scale Photovoltaic Installations Through Enhanced Grounding Using Hydrogel-Graphite Filler

Abstract

Potential‑induced degradation (PID) can reduce photovoltaic (PV) plant output by up to 30 % within a single year, primarily due to voltage‑driven ion migration and leakage currents. This study proposes a cost‑effective mitigation strategy that couples deep, vertical composite electrodes with a hydrogel-graphite backfill (GGG‑mix) [2]. The backfill reduces soil resistivity, stabilizes seasonal fluctuations, and limits the module-ground potential difference. The experimental photovoltaic station with a capacity of 30 kW (located on the territory of the Namangan State Technical University of the Republic of Uzbekistan, which is dry and has a soil consisting of a mixture of sand, stone and soil, the characteristics are the same as in the semi-desert) was equipped with three grounding configurations. Over 52 weeks, the GGG‑mix system lowered ground resistance by 45 % and cut the annual PID power‑loss index from 6.5 % to 1.8 %. Modelling confirmed an equivalent electrode diameter almost eighty‑times larger than a conventional 12 mm rod. Economic analysis indicated a 20 % reduction in installation cost relative to pre‑drilled electrodes. The proposed method therefore offers a practical pathway to PID‑resilient PV deployment in high‑resistivity soils.