Experimental Investigation on Surface Potential Measurement of Tri-Post Insulators Under Electrothermal Coupled Fields

Under DC voltage, the surface of tri-post insulators tends to accumulate charges, distorting electric fields and triggering surface flashover accidents. Currently, there remains a lack of effective experimental setups to investigate surface charge distribution characteristics of tri-post insulators under electrothermal coupled fields. This paper develops a circulating heating device to simulate insulator temperature rise and designs a multi-degree-of-freedom potential measurement mechanism to study surface potential distribution patterns of tri-post insulators under temperature gradients. The results demonstrate that: at room temperature, charge accumulation progresses slowly, with positive charges predominantly aggregating in the central region of the insulator; elevated temperatures alter surface potential distribution characteristics, accelerate the surface charge accumulation process, and induce significant potential enhancement at the post regions.