压痕损伤对高压电缆绝缘层、屏蔽层微观结构及电气性能的影响OA

To investigate the influence of indentation damage on the electrical properties of the insulation and semiconductive shielding layer of high-voltage cross-linked polyethylene(XLPE)cables,sandwich-structured composite specimens(comprising a semiconductive buffer layer,a semiconductive shielding layer,and XLPE insulation)were prepared to simulate the structure of high-voltage XLPE cables.These specimens were subjected to combined indentation damage and thermal aging tests.The microstructure of the specimens was characterized using scanning electron microscopy(SEM),and the volume resistivity was measured before and after the damage tests.The results showed that after the combined indentation damage and thermal aging tests,the surface morphology of all specimens became rougher.The uniformity of the XLPE crystal distribution decreased,the crystal structure was disrupted,and its integrity was reduced.Meanwhile,the carbon black(CB)particles within the semiconductive shielding layer exhibited uneven distribution and severe agglomeration,accompanied by debonding from the matrix.With increasing temperature,the volume resistivity of XLPE gradually decreased.Moreover,as the indentation depth increased,both the volume resistivity and the activation energy of XLPE decreased significantly.After thermal aging with 1.5-fold indentation damage,the activation energy decreased most severely,reaching 40%,indicating a substantial deterioration in insulation performance.In contrast,the volume resistivity of the semiconductive shielding layer showed an increasing trend with increasing damage severity,indicating progressive destruction of the conductive network.At 1.5-fold indentation damage and 90℃,the volume resistivity increased by 66.5%,indicating a significant weakening of its electrical conductivity.