Influence of high frequency stress on the surface charge accumulation and dissipation characteristics of Nomex paper

Existing studies considered that the accumulation and dissipation of surface charge is an important reason for the failure of the insulating material in high-frequency (HF) transformers. However, the specific mechanism is unknown. For the sake of the influence of high frequency voltage on the surface charge accumulation and dissipation characteristics of Nomex paper in HF transformers, an experiment system is established by using the method of surface potential decay. The accumulated and dissipated characteristics of surface charge are investigated. The research says that the initial surface charge reduces with the increasing frequency and the relationship follows an inverse power function. The surface charge decay rate of shows Gaussian distribution and exists a frequency-induced inflection point at 1kHz. The above researches can lay a foundation for the analysis of the failure of the turn-to-turn insulation of high-frequency transformers under high frequency stress.