A Fast Open-Switch Fault and Open-Winding Fault Distinguish Method Based on Voltage Reference Modification

Similar postfault current behaviors make it difficult to distinguish open-winding fault and open-switch fault quickly and accurately, which may lead to motor performance degrade seriously. Although several methods were proposed to distinguish them, they take too long time and false detection often occurs. To solve this issue, a reference voltage correction-based fault distinguish method is proposed in this article. First, an improved adaptive residuals threshold is designed based on the quantitative analysis of residual. It is simple and insensitive to motor operation condition. As a result, the fault can be detected accurately. Second, the relationship between residuals and reference current in open-switch fault and open-winding fault is analyzed, respectively. Based on this relationship, reference voltage correction-based fault location method is proposed. Through varying the reference voltage polarity, the reference current polarity and residual vectors polarity can be changed accordingly. Then, according to the polarity of residual vectors, the fault can be distinguished and located in a shorter time. Finally, the rapidity and accuracy of the fault distinguish method is verified by experimental results.