硫化工艺对抗水树交联聚乙烯绝缘电力电缆工频击穿性能的影响

为了研究不同硫化工艺对抗水树枝交联聚乙烯绝缘电缆击穿性能的影响,建立了相应的试验手段和评价程序。将使用相同导体屏蔽料、抗水树绝缘料、绝缘屏蔽料,并采用5种不同硫化工艺(A、B、C、D、E)生产的电压等级、型号规格相同且结构相似的电缆作为研究对象,每种电缆取6段作样品,共30段。分别对老化前和老化180d后的5种样品进行工频击穿试验,并观察击穿后样品切片的水树枝、界面微孔、突起和绝缘中的微孔、杂质。试验结果表明:经过180d的加速老化后,5种样品中均无微孔、界面光滑、有少量尺寸较小的杂质,不会导致击穿性能下降;不同硫化工艺生产的电缆工频击穿性能表现出明显差异,其中,A硫化工艺生产的电缆工频击穿强度下降了53.53%,击穿后的样品中观察到了水树枝,B、C硫化工艺生产的电缆工频击穿强度也有不同程度的下降,而D、E硫化工艺生产的电缆的工频击穿强度没有降低,说明硫化工艺对工频击穿强度有直接的影响,并建议实际生产中确定硫化工艺时,各区温度设定应逐渐降低,且初始硫化温度不应过低,生产线速度应适当。

Effects of Various Vulcanization Methods on Power Frequency Breakdown Property of Water Treeing Retardant XLPE Power Cable

To investigate the effect of various vulcanization methods on power frequency breakdown property of water treeing retardant XLPE power cable,the test method and quality evaluating program for breakdown property of water treeing retardant XLPE cable were built up.Water treeing retardant XLPE power cable samples with the same rated voltage,the same type and size,and similar structures were made by five different vulcanization methods(A,B,C,D,E) by using the same conductor shield material,the same insulation material and the same insulation shield material.Six samples for each vulcanization method and total thirty samples were made.All the samples were divided into two groups,including before aging and after 180 days accelerated aging.Then,all of the samples were tested one by one to investigate their AC breakdown strengths.Water treeing,void and protrusion in interface between insulation and semi-conductive shield,and void and contaminant in insulation in samples after breakdown were observed.Test results show that there are some small size contaminants and no voids in samples,and interface between insulation and semi-conductive shield are smooth,which can not decrease breakdown strengths.After 180 days aging,AC breakdown strengths of samples made by using a vulcanization method decrease by 53.53% and water trees are observed,AC breakdown strengths of samples made by B and C vulcanization methods also decrease respectively,and AC breakdown strengths of samples made by D and E vulcanization methods do not decrease.The results show that there are direct effects of various vulcanization methods on power frequency breakdown performance of XLPE water treeing retardant power cable,the vulcanization method in practice is also proposed.It is suggested that temperatures in different vulcanization zone should become lower gradually,and the temperature of vulcanization zone 1 should be higher,and the product rate should be proper.