Study on the Inhibition Characteristics of Electrical Trees by the Synergistic Effect of Layered MMT and Spherical SiO₂ in PE

Abstract

In power equipment insulations subjected to prolonged high‐field conditions, the formation of electrical trees is a common occurrence, significantly impacting the service life and operational reliability of the equipment. In this paper, PE composites were prepared by melt blending method using layered nano‐MMT and spherical nano‐SiO2 as fillers to enhance the suppression of electrical trees. The microscopic properties of PE composites were characterized by scanning electron microscopy (SEM), polarizing microscopy (PLM), (DSC). The electrical tree of composites was conducted by the electrical tree test system. Subsequently, the synergistic inhibition of PE by nanoparticles with different morphologies was investigated. Key insights derived from the experimental findings are as follows: first, when MMT is doped with PE, due to the layered structure characteristics, the electro‐acoustic coupling effect, and the coulomb blockade effect, the complexity and complicacy of electron motion trajectory are increased, then the breakdown field strength EB of MMT/PE is increased by 5.74% compared with PE. Thus, the length of electrical trees at the retardation stage decreased by 175 μm, and their morphology changed from branch to bushy branch. Second, when layered MMT and spherical SiO2 are doped in PE simultaneously, the electron travel becomes more complex and tortuous due to the synergistic effect of nanoparticles. Compared with PE, EB of MMT/SiO2/PE is increased by 9.95%, the length entering the retardation stage of electrical trees decreases by 240 μm, and their morphology changes from branch to cluster like. Finally, microscopic and macroscopic results reveal that the combination of layered MMT and spherical SiO2 can effectively suppress the electrical tree growth in PE. These findings underscore the potential of utilizing nanostructured fillers to mitigate the development and expansion of electrical trees in polyethylene insulations, thereby enhancing the overall performance and reliability of power equipment.