The influence of the insulator volume conductivity on charge accumulation in HVDC-GIL

The charge accumulation under DC voltage on the insulator interface is one of the critical factors that restrict the development of HVDC-GIL. The Saturated time and the final electrical field strength is determined by the volume conductivity. Therefore, in this paper, the interface charge accumulation model of operating HVDC-GIL, referred to the actual HVAC-GIL model, was developed to investigate the transient field distribution with different volume conductivity. In the simulation, the saturated time and the field strength of steady state were calculated. It could be found that the volume conductivity has a significant influence on the field strength of steady state and the saturated time. The average value of saturated time is 50h for γ
_VI
=1*10
^-16
S/cm, and 10000h for γ
_VI
=1*10
^-19
S/cm. The results have referenced value on the selection and modification for the insulator materials of HVDC-GIL in the future.