LDPE在植物绝缘油和矿物绝缘油中的直流击穿特性研究

DC breakdown characteristics of LDPE in vegetable insulating oil and mineral insulating oil

随着特高压远距离输电的大规模建设,植物绝缘油取代矿物绝缘油可能成为未来的发展趋势。为了分析不同环境下低密度聚乙烯(LDPE)在不同绝缘油中的直流击穿特性的差异及原因,分别在植物绝缘油和矿物绝缘油中进行了LDPE的直流击穿实验,并通过仿真分析绝缘油放电过程对于LDPE试样击穿的影响。结果表明:LDPE在植物绝缘油中的电气强度明显高于在矿物绝缘油中的击穿强度;两种绝缘油中,试样的沿面闪络特性及击穿点位置也有不同。植物绝缘油放电产生的场强较小,因而植物绝缘油中的LDPE电气强度更高;绝缘油放电过程的差异也是沿面闪络特性及击穿点位置产生差异的原因。

With the large-scale construction of UHV long-distance power transmission,vegetable insulating oil instead of mineral insulating oil may become the future development trend.In order to analyze the differences and reasons of DC breakdown characteristics of LDPE(low density Polyethylene)under different environments,the DC breakdown experiments of LDPE were conducted in vegetable insulating oil and mineral insulating oil,and the impacts of insulating oil discharge process on the breakdown of LDPE samples were analyzed through simulation.The results show that the electric strength of LDPE in vegetable insulating oil is significantly higher than that in mineral insulating oil.The surface flashover characteristics and breakdown points of the two insulating oils are also different.The field intensity generated by discharge of vegetable insulating oil is small,so the breakdown field of LDPE in vegetable insulating oil is higher.The difference of discharge process of insulating oil is also the reason for the difference of flashover characteristics and breakdown point.