Regulation of DC Electric Field Distribution within Insulation Via Positive Temperature Coefficient Material
Zhou Wenjun1, Teng Chenyuan1,2, Zhou Yuanxiang1,2,3, Zhang Ling2, Zhang Yunxiao2
1. School of Electrical Engineering and Automation Wuhan University Wuhan 430072 China; 2. State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing 100084 China; 3. The Wind Solar Storage Division of State Key Laboratory of Power System and Generation Equipment School of Electrical Engineering Xinjiang University Urumqi 830047 China
Abstract:Negative temperature coefficient (NTC) electrical resistivity of insulating materials causes the distortion of DC electric field, increasing the design difficulty of HVDC equipment. The ceramic (0~35%) with positive temperature coefficient (PTC) electrical resistivity was doped into epoxy resin to weaken its temperature dependence of electrical resistivity (0~35%). Thermal conductivity, electrical resistivity-temperature characteristics and DC breakdown strength were tested. The electric field and temperature distribution under temperature gradient were simulated. The higher doping of PTC filler has a better electric field distribution. As for epoxy composite with 20% filler, the thermal conductivity increases by 66% and the radial temperature gradient decreases by 55%; the NTC effect weakens and the activation energy decreases by 35%; the maximum distortion of electric field decreases by 58%, while the DC breakdown strength only decreases by 16%. The PTC effect of fillers mitigating the decline of electrical resistivity with temperature coupled with decreased hot-spot temperature suppresses the distortion of electric field. The optimization of electric field distribution within insulation via PTC materials/epoxy composites has potential to be used in HVDC electrical equipment.
周文俊, 滕陈源, 周远翔, 张灵, 张云霄. 正温度系数材料调控绝缘直流电场分布[J]. 电工技术学报, 2021, 36(14): 3063-3071.
Zhou Wenjun, Teng Chenyuan, Zhou Yuanxiang, Zhang Ling, Zhang Yunxiao. Regulation of DC Electric Field Distribution within Insulation Via Positive Temperature Coefficient Material. Transactions of China Electrotechnical Society, 2021, 36(14): 3063-3071.
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