柔性直流系统短路故障网络阻抗建模与时频特性诊断方法研究  

Research on short circuit fault diagnosis method of DC line based on time-frequency characteristic correlation degree

作　　者：蒋佳丽 刘毅敏[1] 王朋[1] Jiang Jiali;Liu Yimin;Wang Peng(School of Information Science and Engineering,Wuhan University of Science and Technology,Wuhan 430081,China)

机构地区：[1]武汉科技大学信息科学与工程学院,武汉430081

出　　处：《电测与仪表》2022年第10期53-59,99,共8页Electrical Measurement & Instrumentation

基　　金：国家自然科学基金青年基金项目(51907144);中国博士后科学基金面上项目(2017M622512);中央高校基本科研业务费专项资金项目(2042019kf0004)。

摘　　要：针对柔性直流系统直流侧短路故障诊断难题,文章从故障网络精确建模和暂态特征信号分析两个方面展开研究,提出了阻抗网络暂态响应时频特性关联度的故障诊断方法。该方法通过向柔性直流系统线路入口处注入脉冲电压作为激励,实时提取所产生的暂态电流分量,经不同尺度的Mexican Hat变换得到时频能量序列,并构造反映故障网络暂态响应时频能量谱矩阵。同时,建立柔性直流系统精确模型,模拟不同故障点经不同大小电阻的短路故障,构建完整故障样本及其时频特征库,经相似度计算可选出与实测故障特征最相近的样本,确定故障点位置和估计短路电阻大小。最后,对上述原理方法进行算例分析,并与时域方法比较,结果表明文章所述诊断方法及其判据更为准确有效,相关原理正确可行。Aiming at the problem of DC side short-circuit fault diagnosis of flexible DC system,this paper conducts research from accurate modeling of fault network and analysis of transient characteristic signals,and proposes a fault diagnosis method based on the correlation of time-frequency characteristics of impedance network transient response.This method injects a pulse voltage into the DC system line entrance as a stimulus,extracts the transient current component generated in real time,and obtains the time-frequency energy sequence through different scales of the Mexican Hat transform.Meanwhile,an accurate model of a flexible DC system is established to simulate short-circuit faults with different resistances at different fault points,and a complete fault sample and its time-frequency characteristic database are constructed.The similarity calculation can select the closest sample to the measured fault characteristics to determine the fault point location and estimated short-circuit resistance.Finally,an example analysis of the above-mentioned principle and method is performed,and compared with the time-domain method,and the result shows that the diagnostic method and its criteria described in this paper are more accurate and effective,and the relevant principles are correct and feasible.

关 键 词：直流系统 暂态信号 Mexican Hat函数 小波变换 

分 类 号：TM76[电气工程—电力系统及自动化]