Simulation Study on the Effect of Temperature on PD Inside Void Defect Under the Closed Condition

The detection of partial discharges (PDs) is an important part of the insulation condition assessment of gas-insulated switchgear (GIS). Due to the GIS in a server encountering obvious ambient temperature change, the evaluation of PD becomes complicated and indeterminacy. This article aims to study the PDs’ characteristics under different temperatures by modeling the discharge processes, especially inside the void defects, which are unavoidable phenomena limited by the manufacturing technology. Based on the common fluid model, two dielectric barriers are placed between the electrodes to simulate the PD inside the void defect and observe the effect caused by insulating materials. Besides, the parameter-controlled approach is proposed to characterize different discharge temperatures. Notably, the discharge process interacts with streamer propagation and net charge accumulation. The temperature has a vital influence on the impact ionization effect, which not only contributes to the discharge development at the beginning but also slows down the extinguishment due to larger net charge accumulation. Simulation results illustrate that higher temperatures contribute to a lower peak value and shorter lasting time. Compared with the discharge at temperature 303 K, the discharge current amplitude decreased by 26% and 46% at 323 and 343 K, respectively, and the pulse current width decreased by 20% and 30%, which is consistent with the experimental results. Our findings provide a theoretical relationship between the observed discharge current and discharge temperature, which not only helps discharge ambient temperature extrapolation but also can be extended to other discharge conditions.