Degradation Characteristics and Mechanism Analysis of Bimetal Sheet of Low Voltage DC Circuit Breaker
Xing Yunqi1,2, Wang Zihan1, Yang Guangzheng1, Wang Yan1, Zhao Chengchen3
1. State Key Laboratory of Reliability and Intelligence of Electrical Equipment Hebei University of Technology Tianjin 300130 China; 2. People Electric Appliance Group China Wenzhou 325600 China; 3. College of Engineering and Technology Tianjin Agricultural University Tianjin 300392 China
Abstract：A low-voltage DC circuit breaker plays a role in power distribution, control, and protection in low-voltage DC systems. As the core component of overload protection of low-voltage DC circuit breakers, the reliability of thermal release directly affects the safe and stable operation of the DC system. However, during service, the thermal release is subjected to large temperature stress fluctuations, the degradation mechanism is not clear, and the reliability evaluation is difficult. Therefore, the simulation model of thermal release is established to determine the key parameters of thermal release performance degradation. The degradation mechanism of thermal release is revealed by the accelerated life test, and the degradation mechanism of the bimetal sheet is explained from the perspective of molecular dynamics. Firstly, a three-dimensional finite element model of thermal release is established to explore the distribution mechanism of temperature, stress, and deflection of the bimetal sheet. An experimental platform is established, and the active layer expansion coefficient is determined as the key parameter of bimetal sheet performance degradation through orthogonal tests. Secondly, the accelerated stress is temperature, and the accelerated life model is the Arrhenius model. The accelerated life test under 110℃, 130℃, and 150℃ is designed, and the specific bending K is used as the degradation parameter. With the increase in temperature stress, the K decreases by 7.01×10-6/℃ at 150℃ and 3.21×10-6/℃ at 130℃. The e overall decrease in the specific bending K at 110℃ is about 1.03×10-6/℃. The distribution of elements at the interface of the bimetal sheet is observed by SEM. Finally, the molecular dynamics model of the bimetal sheet is established. The diffusion behavior of atoms in the passive layer is more intense than in the active layer. The diffusion behavior of atoms at the interface is further explained by analyzing the mean orientation shift, diffusion activation energy, and diffusion factor of different atoms. The results show that the diffusion probability of all atoms was almost the same. Due to the low diffusion activity of the passive layer Ni atom, the diffusion is more intense. The performance degradation mechanism of the overload protection element of low-voltage DC circuit breakers is revealed from a microscopic point of view. The following conclusions can be drawn. (1) The active layer expansion coefficient is a key parameter affecting the degradation of bimetal sheets, so specific bending K can be used as a characteristic parameter characterizing the degradation of bimetal sheets. (2) The degradation rate of specific bending K is almost the same at the same temperature, and the decrease rate of specific bending K is greater with the increase of temperature. (3) The molecular dynamics analysis shows that the diffusion of atoms at the interface changes active and passive expansion coefficients, and the diffusion of atoms in the passive layer is intense. The degradation mechanism of the bimetal sheet is explained from the microscopic view.
邢云琪, 王子涵, 杨广正, 王妍, 赵成晨. 低压直流断路器双金属片性能退化特性及机理分析[J]. 电工技术学报, 2024, 39(22): 7266-7277.
Xing Yunqi, Wang Zihan, Yang Guangzheng, Wang Yan, Zhao Chengchen. Degradation Characteristics and Mechanism Analysis of Bimetal Sheet of Low Voltage DC Circuit Breaker. Transactions of China Electrotechnical Society, 2024, 39(22): 7266-7277.
[1] 贾申利, 史宗谦, 王立军. 真空断路器用于直流开断研究综述[J]. 高压电器, 2017, 53(3): 12-16. Jia Shenli, Shi Zongqian, Wang Lijun.Review on the research of vacuum circuit breaker for DC breaking[J]. High Voltage Apparatus, 2017, 53(3): 12-16. [2] 荣命哲, 杨飞, 吴翊, 等. 直流断路器电弧研究的新进展[J]. 电工技术学报, 2014, 29(1): 1-9. Rong Mingzhe, Yang Fei, Wu Yi, et al.New developments in switching arc research in DC circuit breaker[J]. Transactions of China Electrotechnical Society, 2014, 29(1): 1-9. [3] 束洪春, 邵宗学, 旷宇. 基于改进型限流混合式直流断路器的开断时序优化研究[J]. 电工技术学报, 2023, 38(22): 6176-6187. Shu Hongchun, Shao Zongxue, Kuang Yu.Research of opening timing optimization based on improved current-limiting hybrid DC circuit breaker[J]. Transactions of China Electrotechnical Society, 2023, 38(22): 6176-6187. [4] 李浩, 裴翔羽, 李泽文, 等. 具备故障电流限制能力的多端口直流断路器[J]. 电工技术学报, 2023, 38(10): 2818-2831. Li Hao, Pei Xiangyu, Li Zewen, et al.A multi-port DC circuit breaker with fault-current limiting capability[J]. Transactions of China Electrotechnical Society, 2023, 38(10): 2818-2831. [5] 周阳, 王东, 戴铭磊. 小型断路器双金属片瞬时热分布研究[J]. 现代建筑电气, 2022, 13(10): 6-10. Zhou Yang, Wang Dong, Dai Minglei.Study on instantaneous heat distribution and deformation of bimetallic sheet of miniature circuit breaker[J]. Modern Architecture Electric, 2022, 13(10): 6-10. [6] 潘庆元. 小型断路器双金属片热弯曲特性的实验仿真[J]. 电器与能效管理技术, 2022(2): 46-52. Pan Qingyuan.Experimental simulation of bimetallic strip thermal flexivity specialty in miniature circuit breaker[J]. Electrical & Energy Management Tech- nology, 2022(2): 46-52. [7] 胡建国, 王景凯, 黄和平. 影响双金属片式产品动作特性的因素及其参数设计[J]. 电器与能效管理技术, 2020(6): 30-35. Hu Jianguo, Wang Jingkai, Huang Heping.Factors affecting performance characteristics of bimetallic strip products and parameter design[J]. Electrical & Energy Management Technology, 2020(6): 30-35. [8] 陈维, 张国钢, 张鹏飞, 等. 低压开关电器主电路温度场的有限元分析[J]. 低压电器, 2010(20): 1-4. Chen Wei, Zhang Guogang, Zhang Pengfei, et al.Finite element analysis of temperature field of main circuit in low voltage apparatus[J]. Low Voltage Apparatus, 2010(20): 1-4. [9] Liu Guojin, Miao Jianhua, Zhao Xingzhou, et al.Life prediction of residual current circuit breaker with overcurrent protection based on BP neural network optimized by genetic algorithm[J]. Journal of Electrical Engineering & Technology, 2022, 17(3): 2003-2014. [10] 李奎, 郝运佥, 赵成晨, 等. 基于马尔可夫过程的漏电保护器服役状态及其可靠性分析[J]. 电工技术学报, 2023, 38(18): 5061-5076. Li Kui, Hao Yunqian, Zhao Chengchen, et al.Service states and reliability analysis of residual current device based on Markov process[J]. Transactions of China Electrotechnical Society, 2023, 38(18): 5061-5076. [11] 王国栋, 周凯, 李原, 等. 基于失效时间统计特性的交联聚乙烯电寿命模型修正[J]. 电工技术学报, 2023, 38(4): 1042-1050. Wang Guodong, Zhou Kai, Li Yuan, et al.Modification of cross-linked polyethylene electrical life model based on statistical characteristics of failure time[J]. Transactions of China Electro- technical Society, 2023, 38(4): 1042-1050. [12] Peng C Y, Tseng S T.Progressive-stress accelerated degradation test for highly-reliable products[J]. IEEE Transactions on Reliability, 2010, 59(1): 30-37. [13] 代岭均, 邹亮, 郭凯航, 等. 纳米晶合金晶粒尺寸与体积分数对高频磁损耗特性影响分析[J]. 电工技术学报, 2023, 38(18): 4853-4863. Dai Lingjun, Zou Liang, Guo Kaihang, et al.Analysis of grain size and volume fraction of nanocrystalline alloy on high frequency magnetic loss characteri- stics[J]. Transactions of China Electrotechnical Society, 2023, 38(18): 4853-4863. [14] Li Chang, Li Dongxu, Tao Xiaoma, et al.Molecular dynamics simulation of diffusion bonding of Al-Cu interface[J]. Modelling and Simulation in Materials Science and Engineering, 2014, 22(6): 065013. [15] 崔曼, 胡震, 张腾飞, 等. 基于壳温信息的功率器件可靠性分析[J]. 电工技术学报, 2023, 38(24): 6760-6767. Cui Man, Hu Zhen, Zhang Tengfei, et al.Reliability analysis of power device based on the case temperatures[J]. Transactions of China Electrotech- nical Society, 2023, 38(24): 6760-6767. [16] 许文良, 何为龙. 低压电器热过载保护及热双金属片仿真设计[J]. 电器与能效管理技术, 2021(6): 41-46. Xu Wenliang, He Weilong.Thermal overload protection for low voltage apparatus and simulation of thermal bimetal[J]. Electrical & Energy Management Technology, 2021(6): 41-46. [17] 胡金利, 卢为民, 姜义非. 小型断路器双金属片温升仿真研究[J]. 电器与能效管理技术, 2020(12): 60-66. Hu Jinli, Lu Weimin, Jiang Yifei.Simulation study on temperature rise of bimetal in MCB[J]. Electrical & Energy Management Technology, 2020(12): 60-66. [18] 毛国伟. 塑壳断路器热双金属片动作特性仿真分析[J]. 电子元器件与信息技术, 2022, 6(11): 22-24, 58. Mao Guowei.Simulation analysis of action characteristics of plastic case circuit breaker hot bimetal[J]. Electronic Components and Information Technology, 2022, 6(11): 22-24, 58. [19] 于永站, 谭昌柏, 张金泉, 等. 塑壳断路器热脱扣特性的仿真与试验分析[J]. 低压电器, 2012(7): 5-9, 18. Yu Yongzhan, Tan Changbai, Zhang Jinquan, et al.Simulation and experiment research on thermal tripping capacity of moulded case circuit breaker[J]. Low Voltage Apparatus, 2012(7): 5-9, 18. [20] Bonny G, Pasianot R C, Castin N, et al.Ternary Fe-Cu-Ni many-body potential to model reactor pressure vessel steels: First validation by simulated thermal annealing[J]. Philosophical Magazine, 2009, 89(34/35/36): 3531-3546. [21] Choi W M, Jo Y H, Sohn S S, et al.Understanding the physical metallurgy of the CoCrFeMnNi high-entropy alloy: an atomistic simulation study[J]. NPJ Com- putational Materials, 2018, 4: 1. [22] Karls D S, Bierbaum M, Alemi A A, et al.The OpenKIM processing pipeline: a cloud-based auto- matic material property computation engine[J]. The Journal of Chemical Physics, 2020, 153(6): 064104. [23] Liu Huaqiang, Deng Wei, Ding Peng, et al.Investigation of the effects of surface wettability and surface roughness on nanoscale boiling process using molecular dynamics simulation[J]. Nuclear Engin- eering and Design, 2021, 382: 111400.
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