Differential Protection of Distribution Network Based on VMD and Duffing Oscillator
张健宝 1王磊 1江伟建2
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作者信息
1. 上海电力大学电气工程学院,上海 200090
2. 国网浙江省电力有限公司嘉兴供电公司,浙江嘉兴 314000
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摘要
配电网经消弧线圈接地,发生单相接地故障时,存在着故障特征弱、不明显的特点,很难准确找到故障线路,近年来随着通信等相关技术的发展,差动保护成本不断降低,使得配网差动保护的实现成为可能.提出变分模态分解(variational mode decomposition,VMD)和Duffing振子系统相结合的选线方法,VMD获取暂态零序电流的高频分量,将线路两侧高频零序电流相位差加入Duffing系统中,通过分析线路两侧高频分量相位差和Duffing系统状态的联系,构造了基于动态时间弯曲(dynamic time warping,DTW)描述系统状态变化的区内区外故障判据,实现故障准确定位,最后通过数值仿真证明该选线方法在不同过渡电阻、有分布式电源等情况下能够快速、准确定位线路上发生单相接地故障的区段,验证了该方法的有效性.所提故障区段定位算法可以有效提取故障特征,提高了保护的可靠性和选线的准确率.
Abstract
The distribution network is grounded through arc suppression coil.When a single-phase grounding fault occurs,the faulting characteristics are often weak and unobvious,which makes it difficult to accurately locate the fault line.In recent years,with the development of communication and other related technologies,the cost of differential protection has decreased continuously,which makes it possible to realize the differential protection of distribution network.Therefore,a line selection method based on variational mode decomposition (VMD) and Duffing oscillator system is proposed.Firstly,the high-frequency component of transient zero-sequence current is obtained with VMD,and the phase difference of high-frequency zero-sequence current on both sides of the line is added to the Duffing system.And then,by analyzing the relationship between the phase difference of high-frequency components on both sides of the line and the state of the Duffing system,a fault criterion based on dynamic time warping (DTW) is constructed to realize the accurate location of the fault.Finally,numerical simulation proves that the proposed line selection method can quickly and accurately locate the single-phase ground fault sections for the lines that have different transition resistances and distributed power sources.The proposed fault section localization algorithm can effectively extract fault characteristics,thereby improving the reliability of protection and the accuracy of line selection.
关键词
差动保护/小电流系统/变分模态分解/Duffing振子/动态时间弯曲
Key words
differential protection/small current system/variational mode decomposition/Duffing oscillator/dynamic time warping
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