The morphology analysis of arc plasma inside a low‐voltage circuit breaker is a practical approach to investigate its current interruption performance. It is a typical ill‐posed problem to determine the arc current distribution from the induced magnetic field of arc plasma. The regularization method has been proven effective in solving inverse magnetic problems. However, the arrangement of current‐carrying conductors in arc chamber and the time‐varying characteristics of arc plasma make it difficult to yield a reasonable inverse solution. In this paper, a heuristic search algorithm is proposed. The solving procedure is as follows. First, a series of inverse models with supposed arc root positions are created dynamically. Second, the Tikhonov regularization method with quasi‐optimality criterion is applied to solve the inverse problems iteratively. Then each solution is evaluated and the best solution can be found out. After all the models according to the different arcing stages have been solved, an image list of current density distribution of arc plasma is formed. An experimental system measuring the 2D magnetic field of arc plasma has been built, in which a 64‐unit hall‐effect sensor array and the corresponding data acquisition system are adopted to detect the arc magnetic field; meanwhile, the waveforms of arc voltage and current are recorded by a digital oscilloscope and the optical images of arc plasma are captured by a high speed charge‐coupled device camera. The experimental results show that the inverse results of arc current density distribution are in accordance with the optical images. The proposed inverse method provides a noninvasive technique for the diagnosis of arc plasma.

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基于启发式搜索和正则化反演方法的电弧等离子体空间重构研究

低压断路器内部电弧等离子体的形态分析是研究其电流中断性能的实用方法。根据电弧等离子体的感应磁场确定电弧电流分布是一个典型的不适问题。正则化方法已被证明可有效解决逆磁问题。但是，由于电弧室中载流导体的布置以及电弧等离子体的时变特性，很难产生合理的逆解。本文提出了一种启发式搜索算法。解决步骤如下。首先，动态创建一系列具有假定弧根位置的逆模型。其次，采用准最优准则的Tikhonov正则化方法迭代求解逆问题。然后评估每个解决方案，然后找出最佳解决方案。在解决了根据不同电弧阶段的所有模型之后，形成了电弧等离子体的电流密度分布的图像列表。建立了一个测量电弧等离子体二维磁场的实验系统，采用64个单位的霍尔效应传感器阵列和相应的数据采集系统来检测电弧磁场。同时，电弧电压和电流的波形由数字示波器记录，电弧等离子体的光学图像由高速电荷耦合器件照相机捕获。实验结果表明，电弧电流密度分布的反结果与光学图像一致。所提出的逆方法提供了一种非侵入性技术来诊断电弧等离子体。