换流变阀侧套管环氧浸纸芯体模型气-固界面电荷积聚特性OA

The valve-side bushing of ultra-high voltage(UHV)converter transformers is a key component in DC power transmission systems,playing a critical role in ensuring the safe and stable operation of the power grid.However,in re-cent years,surface flashover failures have frequently occurred at the SF6-solid insulation interface of valve-side bushings,and the surface charge distribution at this interface directly affects insulation performance.Therefore,understanding the charge accumulation characteristics at the SF6-solid interface is essential for maintaining the safe and stable operation of valve-side bushings.In this study,a charge measurement system was developed to assess the gas-solid interface of a scaled epoxy-impregnated paper model of a valve-side bushing.Surface charge distributions were measured under DC voltage in an SF6 environment,including both short-term and long-term behaviors.Experimental results reveal that two charge distribution patterns appear under DC voltage,namely,a fundamental pattern determined by the bushing structure,and a unipolar spot pattern influenced by surface conditions.Finally,simulation analysis was conducted to investigate the effects of solid current,gas current,and surface current components on surface charge accumulation.It is concluded that the surface current components is the main influencing factor of the core model surface charge accumulation.