最小能量法因子对RSO法检测匝间短路故障的时间差定位影响分析

Influence of Minimum Energy Factor on Time Difference Location Accuracy of RSO for Detecting Inter-turn Short Circuit Fault

为实现重复脉冲法检测匝间短路故障的早期预警与准确定位,文中采用改进最小能量法查找脉冲起始时刻并以此计算重复脉冲信号的传播时间差,从而实现提高故障定位精度的目的。通过在发电机转子绕组中的检测实例,分析了最小能量法因子α在不同取值下对绕组无缺陷、轻微缺陷、重度缺陷以及严重缺陷等4种情况下时间差计算准确度的影响。结果表明,特征波形凸起越大,即信噪比越高,则时间差计算越准确。随后基于Monte Carlo方法对各种缺陷情况下的30组数据分别进行统计分析。结果表明:无论是何种缺陷,影响因子取值都存在一个合理区间,在该选择区间内选取因子α的值,可提高时间差计算的准确度,从而提高匝间短路定位的准确程度。最后提出了先判断缺陷严重程度,再选取合适的计算因子α,最后进行时间差计算的缺陷定位方法。

In order to realize the early warning and accurate positioning for the detection of inter-turn short circuit fault by recurrent surge oscilloscope (RSO) method, the improved minimum energy method is presented in this paper to determine the start time of the recurrent surge pulse and estimate signals propagating time difference so as to improve the accuracy of fault location. The detection in generator rotor winding is taken as an analysis example. In the four cases that there are no defects, slight defects, severe defects and serious defects in windings, the influence of the minimum energy factor a on the accuracy of wave front estimation is analyzed. The result indicates that the larger the protruding of the characteristic waveform, in other words the higher the signal to noise ratio, the more accurate the time difference calculation will be. Then thirty sets of RSO data collected in the test of different cases are statistically analyzed based on the Monte Carlo method. The results show that no matter what kind of fault is, the factor a always has a reasonable selection range which can improve the calculation accuracy of the wave front as well as the defect location of the inter-tum shortcircuit. Finally, the defect location method that judges the severity of the defect firstly, selects the appropriate computing factor secondly and calculates of time difference at last,is proposed.