Study on Charge Accumulation Characteristics of Basin Insulators with Polarity Reversal

The insulator of a DC gas-insulated transmission line (DC-GIL) will accumulate surface charge under the action of polarity reversal, leading to the risk of flashover. In this paper, the actual GIL model was used for simulation. Based on the 3D horizontally mounted GIL model, COMSOL finite element simulation software was used to study the surface charge accumulation characteristics of DC GIL basin insulators under the action of polarity reversal. In order to prove the correctness of the mathematical model, the same model as A. Winter et al. was established and compared with the experimental data to verify the correctness of the mathematical model in this paper. The results show that the surface charge density of the insulator is almost constant during the voltage polarity reversal process. When the reversal time is 60 s, the surface electric field intensity of the convex surface of the basin insulator increases by 23.7% and that of the concave surface increases by 33.2% compared with the steady state before and after reversal. As a result, flashover is more likely to be triggered during voltage polarity reversal.