基于电接触元件暂态热路建模的接触电阻测量研究

摘要

At present the main method of measuring contact resistance is bridge method or detecting voltage/current, the shortage is only suitable for offline applications. A new method of online measuring contact resistance based on the transient thermal circuit model is raised. Firstly the theoretical physical model and the radial transient thermal circuit model of electric contact components are established, the thermal circuit response equation is concluded based on theory analysis. Then the axial heat transfer numerical analysis model is established. Finally the contact resistance model considering temperature and current is derived from the theory analysis, a method of measuring contact resistance by using the curve of thermal time constant is raised. A lot of theoretical analysis/calculation and finite element analysis of ANSYS simulation results show that the method can accurately obtain the value of the contact resistance, which provides theoretical support for on-line monitoring of contact resistance and thermal defect analysis of electric power equipment.%目前，接触电阻的检测主要是电压电流法或电桥法，其不足是仅适于离线应用。提出了一种在线式的接触电阻间接测量新方法。首先在建立电接触元件的理论物理模型和径向暂态热路分析模型的基础上，推导出热路响应方程；然后再在建立元件轴向热传导数值分析模型的基础上，最终推导出计及温度和电流的接触电阻曲线关系，提出通过曲线的时间常数计算电接触元件的接触电阻。大量的理论分析、计算与有限元分析ANSYS仿真表明，所研究的测量方法可以准确求取接触电阻的值，为电气设备的在线监测和热缺陷分析提供了理论依据。