基于陷阱密度的双向拉伸聚丙烯薄膜耐γ辐照积累剂量阈值评估  

Threshold Evaluation ofγIrradiation Accumulated Dose of BOPP Film Based on Trap Density

作　　者：王雨橙 李化[1,2] 王哲豪[1] 林福昌 Wang Yucheng;Li Hua;Wang Zhehao;Lin Fuchang(State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology,Wuhan 430074 China;Key Laboratory of Pulsed Power Technology Huazhong University of Science and Technology Ministry of Education,Wuhan 430074 China)

机构地区：[1]强电磁工程与新技术国家重点实验室(华中科技大学),武汉430074 [2]脉冲功率技术教育部重点实验室(华中科技大学),武汉430074

出　　处：《电工技术学报》2023年第18期5039-5048,共10页Transactions of China Electrotechnical Society

基　　金：国家自然科学基金资助项目(51822704)。

摘　　要：聚合物电介质在接受辐照后,电气性能会下降,可能使电气系统在发生电气故障前因电介质劣化而过早地终止使用寿命。以双向拉伸聚丙烯(BOPP)薄膜为对象,研究了γ辐照积累剂量对结晶度和陷阱参数的影响规律。依据辐照陷阱产生模型,定义辐照后陷阱密度增加系数ktrap以表征薄膜电气性能劣化程度,并提出了γ辐照积累剂量阈值评估方法。研究结果表明,γ辐照积累剂量超过10 kGy时,BOPP薄膜的结晶度显著下降,陷阱深度随辐照积累剂量的增加而增大,陷阱密度随辐照积累剂量的增加呈指数形式增大。根据陷阱密度随辐照积累剂量的分段规律,得到BOPP薄膜劣化的起始辐照积累剂量阈值为10 kGy,显著劣化的阈值为80 kGy。The service life of electrical systems usually depends on the endurance limit of the polymer dielectric.After irradiation,the macromolecular structure changes,and the electrical performance deteriorates,which may cause the electrical system to terminate its service life prematurely due to dielectric degradation before electrical failure.The previous studies mostly used macroscopic electrical parameters to characterize the radiation degradation of polymer films,including conductivity,dielectric loss,and breakdown strength.These parameters are easily affected by working conditions such as applied voltage and temperature.Compared with the macroscopic properties,the intrinsic microscopic properties,such as crystallization and space charge characteristics,can reflect the deterioration more accurately.In this paper,biaxially oriented polypropylene film(BOPP)as the object for capacitors was irradiated in the air.Theγirradiation dose is 0.2,0.5,1,5,10,50,100,500 and 1000 kGy.First,the surface morphology of the films before and afterγirradiation was observed.Then the heat flow curves of the films were measured by the differential scanning calorimetry(DSC)method,and the trap parameters of the films were measured by the thermally stimulated depolarization current(TSDC)method.The effects of accumulatedγirradiation dose on crystallinity,melting point,and trap parameters were studied.Finally,the threshold evaluation method of the accumulatedγirradiation dose was proposed based on the irradiation-induced trap generation model.The surface morphology observation shows thatγirradiation does not affect the shape and size of the grain on the surface of the film.The DSC test results show that the melting point and crystallinity of the films after irradiation have no significant changes when the accumulatedγirradiation dose D does not exceed 10 kGy.When D exceeds 10 kGy,the crystallinity and melting point decrease gradually with the increase of the accumulated irradiation dose.The variation of crystallinity with the accumulated

关 键 词：BOPP薄膜 Γ辐照 结晶度 陷阱参数 阈值评估 

分 类 号：TM852[电气工程—高电压与绝缘技术]