Mechanical Characteristics of 110 kV Grafted Polypropylene Insulation Power Cable Body

In recent years, polypropylene (PP) insulation power cables have been vigorously developed and promoted due to its excellent high temperature electrical performances and environmentally friendly properties. However, at present, thermal shrinkage, low temperature shrinkage and aging mechanical characteristics of the polypropylene cables are not thoroughly studied, especially the mechanical characteristics of PP cable after cabling. In order to meet the needs of cable laying and maintenance in operation, thermal shrinkage, low temperature shrinkage, and body insulation aging tests of 110 kV grafted PP insulation power cables were carried out, horizontal and longitudinal comparative analysis was made. Results showed that thermal shrinkage of grafted PP insulation power cables was lower than that of cross-linked polyethylene (XLPE) cables at operating temperature. After low temperature test with −40 ℃ and 48 h, the shrinkage of insulation outer perimeter of grafted PP cables was only 0.46% to 0.68%, and shrinkage rate of longitudinal length of PP cables with non-conductor was closed to 0.60%, while that of PP cables with conductor was only about 0.20%. After 360 h of aging at 150 ℃, mechanical characteristics of grafted PP cables could still meet the requirements of no more than ±25% change rate of tensile strength and break elongation. In this paper, mechanical characteristics of grafted PP insulation power cables were preliminarily explored, which could provide the basis for engineering design and operation criteria of grafted PP power cables in the future.