基于分形理论的直流系统环网接地故障检测方法研究

Research on grounding fault detection method of DC system loop based on fractal theory

随着时代的进步以及企业的发展,越来越多的地方对电能供应提出了更严格的要求。为了保证重要负载供电的可靠性,常常采用分段式环网供电,而环网在提高支路供电可靠性的同时也增加了结构的复杂性,当环网发生接地故障时,检测中遇到的困难会大量增加。文章基于分形理论,利用低频信号注入法,小波变换提取环网支路的信息,根据小波提取的支路信息来计算支路电流信号的分形维数,并由此得出分形维数随支路绝缘情况的变化趋势,进而判断支路的绝缘情况。

With the progress of the times and the development of enterprises,more and more places put forward stricter requirements for power supply.In order to ensure the reliability of power supply for important loads,segmented ring network is often used for power supply.While the ring network improves the reliability of branch power supply,it also increases the complexity of structure.When the ring network has grounding fault,the difficulties encountered in detection will increase greatly.Based on the fractal theory,this paper uses the low-frequency signal injection method and wavelet transform to extract the information of the loop network branch,calculates the fractal dimension of the branch current signal according to the branch information extracted by wavelet,and obtains the change trend of the fractal dimension with the branch insulation,so as to judge the branch insulation.