摘要
通过建模仿真及实验等手段对低压系统短路故障的特征进行了分析研究。在此基础上 ,选用三次B样条函数为小波函数 ,对低压系统短路电流实施二进小波变换 ,获得各尺度小波变换的平滑分量及小波分量。通过研究发现 ,在短路发生后极短时间内 ,当短路电流变化得还未对线路及设备造成威胁时 ,小波分量值与正常运行时相比已达较大值 ,表现出较明显的故障特征 ,且高尺度下的小波分量还可有效抑制噪声干扰的影响。最后通过该算法的实时性分析 ,说明用三次B样条小波分解算法对低压系统短路故障进行早期预测是有效的。
The characteristics of the short circuited fault in low voltage system are studied by means of simulation and experiment.The distinguished characteristic of the short circuited fault is that the derivative of current drastically increases at the incipience of the fault.But it's risk to take the derivative of current as faulty criterion because of the influence of noise.The quadratic B spline wavelet transform can smooth and denoise the fault current signal before derivative operation,so it's applied in this paper.Research have found that in the incipience of short circuited fault,the wavelet coefficients in different scales might reach much larger values than that in normal condition whereas the short circuited fault current itself haven't been developed.So the quadratic B spline wavelet transform can be used to detect the early appearance of short circuited fault.The results showed that this approach is practical and effective.
出处
《电工技术学报》
EI
CSCD
北大核心
2003年第2期91-94,共4页
Transactions of China Electrotechnical Society
