SiC掺杂对直流电缆附件用硅橡胶材料非线性电导特性的优化研究  

Optimization of Nonlinear Conductivity Characteristics of Silicone Rubber Materials for DC Cable Accessories by SiC Doping

作　　者：伍珈乐 熊沛琪 邢泽西 龚阳智 卞星明 Wu Jiale;Xiong Peiqi;Xing Zexi;Gong Yangzhi;Bian Xingming(State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power University,Beijing 102206,China;State Grid Fuzhou Electric Power Supply Company,Fuzhou 350009,China)

机构地区：[1]新能源电力系统国家重点实验室(华北电力大学),北京102006 [2]国网福州供电公司,福州350009

出　　处：《电工技术学报》2023年第5期1129-1138,共10页Transactions of China Electrotechnical Society

基　　金：国家电网有限公司总部科技项目资助(7000-202158440A-0-0-00)。

摘　　要：电气设备部件的性能提升不仅要依靠传统几何方法来改善绝缘结构,更要侧重于对绝缘材料自身性能的优化。该文通过实验研究了碳化硅(SiC)/硅橡胶复合材料的直流电导特性和直流击穿特性。随着温度升高,SiC晶格散射会阻碍载流子迁移,宏观上表现为电导特性非线性系数降低,而更多高能载流子的出现则会使非线性区阈值场强减小。随着SiC体积分数及粒径的增加,复合材料直流击穿场强虽有一定程度降低,但整体仍满足运行设计要求。在兼顾关键位置电场分布、损耗功率及局部温升的条件下,该文通过仿真探究了非线性电导特性参数的合理范围,所制备的掺杂10%体积分数SiC/硅橡胶复合材料作为应力锥增强绝缘参与电场调控,可有效改善电缆终端内部电场强度分布,应力锥导体锥面处电场强度降低幅度达到50%。该研究结果有望从材料改性角度为提升电缆附件性能提供思路。For HVDC cables,the insulation level is the core issue,and also the key factor affecting the equipment capacity and long-term operation stability.In the cable accessories,because the electrical conductivity and dielectric constant of the insulating material cannot achieve continuous transition,the electric field distribution is highly uneven.The field strength borne by the insulating part of the accessories is several times the average value of the overall field strength,which may cause local electric field distortion inside the accessories and even directly cause insulation failure.Reasonable improvement of the electric field distribution at key positions are critical to the insulation of high-voltage cable terminal.It is an effective scheme to regulate the field distribution in the cable terminal by using nonlinear material whose electrical conductivity changes adaptively with the applied field.Silicon carbide(SiC),which has the advantages of low chemical activity,moderate cost and good thermal conductivity,is selected to modify the silicone rubber(SR)matrix.The DC breakdown and nonlinear conductivity characteristics of SiC/SR composites were experimentally investigated.The results show that although the breakdown strength of the composite material decreases to a certain extent after doping with SiC,it still meets the requirement of operation.With the increase of temperature,the SiC lattice scattering will hinder the carrier migration,resulting in the decrease of nonlinear coefficient,while the appearance of more high-energy carriers will reduce the threshold field of the conductivity.When nonlinear materials are used to regulate the electric field of the equipment,only when the conductivity characteristics of the materials match the operation environment can a better field grading effect be achieved.Under the conditions of considering the field distribution,power loss and local temperature rise,the suitable parameters range of nonlinear conductivity were determined quantitatively.The results show that when the

关 键 词：硅橡胶 非线性电导特性 直流击穿特性 电场调控 

分 类 号：TM215[一般工业技术—材料科学与工程]