Abstract

We propose an original method for numerical calculation of heating of high-current electric contacts in the closed state by pulsed currents with a duration comparable with the period of the industrial-frequency current. Such regimes are typical of current-carrying systems of high-voltage electric facilities during switching high-power loads, during failure in electric transmission lines, and in testing devices for stability to short-circuit current. In constructing the solution, we assume that the time dependences of the current and voltage across the contacts are known. We have developed an iteration procedure for solving a series of thermoelectric problems, which makes it possible to calculate the temperature distribution in contacts and to trace its variation by selecting the size of contact spots in each time interval. We have tested this method by comparing the results of calculation with experimental data obtained for cylindrical copper contacts heated to melting by pulsed currents in a wide range of contact pressure forces. The current actions are selected so that melting occurs during extremely short time (first quarter of the period).

中文翻译：

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用脉冲电流计算闭合大电流电触头的方法

摘要

我们提出了一种原始方法，用于通过脉冲电流对闭合状态下的大电流电触点的加热进行数值计算，其持续时间可与工频电流的周期相媲美。在切换大功率负载期间，输电线故障以及测试设备对短路电流的稳定性期间，这种状态对于高压电力设施的载流系统来说是典型的。在构造解决方案时，我们假设触点上电流和电压的时间依赖性是已知的。我们已经开发出一种迭代程序来解决一系列热电问题，从而可以通过选择每个时间间隔内的接触点大小来计算接触点的温度分布并跟踪其变化。我们通过将计算结果与在宽范围的接触压力范围内被脉冲电流加热熔化的圆柱形铜触点获得的实验数据进行比较，对这种方法进行了测试。选择当前动作，以便在极短的时间内（周期的第一季度）发生熔化。