摘要
低压直流断路器的热脱扣器主要通过热双金属片受热弯曲完成过载保护动作。为分析服役时热双金属片的温度分布,在有限元软件COMSOL中建立实际工况的低压直流断路器电-热-流体耦合模型,得到热脱扣器部分的温升曲线,并通过实验验证仿真结果的正确性。仿真与实验结果表明,间接加热式的热双金属片以及加热元件都呈现出中间温度高、两端温度低的分布特点。通过分析断路器内部的热传导、热对流以及热辐射,对热双金属片和加热元件的传热方式进行研究,得出间接加热式热双金属片主要通过热对流进行加热,在温度较高时热辐射也不能忽略。同时利用Levenberg-Marquardt最小二乘法对热双金属片的非线性温度进行拟合,对其热时间常数进行修正,修正后的热时间常数能够反映断路器的实际工作状况,可为热脱扣器的退化研究与优化设计提供参考。
Low-voltage DC circuit breaker thermal trip completes the overload protection action mainly by means of the thermal bimetal sheets bending due to heat.In order to analyze the temperature distribution of the thermal bimetal sheets during service,an electric-thermal-fluid coupling model of the low-voltage DC circuit breaker is established in finite element software COMSOL for the actual working condition,so as to obtain the temperature rise curve of the thermal trip.The correctness of the simulation results is verified by experiments.The simulation and experimental results indicate that the indirectly heated thermal bimetal sheets and the heating elements exhibit the distribution features:high temperatures in the central region and low temperatures at the both extremities.The heat transfer mode of the thermal bimetal sheet and the heating element is researched by analyzing the heat conduction,heat convection,and heat radiation within the circuit breaker.It shows that the indirectly heated thermal bimetal sheet is primarily heated by means of the thermal convection,and the thermal radiation cannot be disregarded at higher temperatures.The nonlinear temperature of the thermal bimetal sheet was fitted by means of the Levenberg-Marquardt least squares method,and its thermal time constant was corrected.The corrected thermal time constant can reflect actual working condition of the circuit breaker,and can provide a reference for the degradation research and optimization design of the thermal trip.
作者
苏秀苹
王东跃
贾彦庆
王林林
SU Xiuping;WANG Dongyue;JIA Yanqing;WANG Linlin(School of Electrical Engineering,Hebei University of Technology,Tianjin 300130,China;State Key Laboratory of Reliability and Intelligence of Electrical Equipment,Hebei University of Technology,Tianjin 300130,China)
出处
《现代电子技术》
北大核心
2025年第20期120-126,共7页
Modern Electronics Technique
基金
国家自然科学基金项目(51937004)。
关键词
低压直流断路器
热脱扣器
热双金属片
温度场
多物理场耦合
有限元分析
热时间常数
low-voltage DC circuit breaker
thermal trip
thermal bimetal sheet
temperature field
multi-physical field coupling
finite element analysis
thermal time constant
作者简介
苏秀苹(1966—),女,天津人,教授,博士生导师,研究方向为电器可靠性、电器现代设计技术。;王东跃(1999—),男,河北保定人,硕士研究生,主要研究方向为电器现代设计技术。
