110 kV接枝聚丙烯绝缘电力电缆本体机械特性
Mechanical Characteristics of 110 kV Grafted Polypropylene Insulation Power Cable Body
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摘要: 近年来,聚丙烯绝缘电力电缆因其优异的高温电气性能和环境友好属性得到了大力发展和推广应用。然而,目前业界对聚丙烯电缆热收缩、低温收缩、老化机械特性的认识尚不全面,尤其是对成缆后聚丙烯电缆本体机械特性的研究较少。为满足电缆敷设和运行维护的需要,文中开展了110 kV接枝聚丙烯绝缘电力电缆的热收缩、低温收缩及本体绝缘空气热氧老化试验,并进行横向和纵向的对比分析。结果表明,接枝聚丙烯电缆绝缘在运行温度下的热收缩率比交联聚乙烯电缆低;经过−40 ℃低温试验48 h后,接枝聚丙烯电缆绝缘外周长收缩率仅0.46%至0.68%,无导体聚丙烯电缆纵向长度的收缩率约0.60%,而有导体的仅为0.20%左右;在150 ℃下空气热老化360 h后,接枝聚丙烯电缆的机械特性仍满足抗张强度变化率和断裂伸长率变化率不超过±25%的要求。文中工作对接枝聚丙烯绝缘电力电缆的机械特性进行了初步探索,为后续接枝聚丙烯电缆的工程设计和运行准则制定提供了依据。Abstract: 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.
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