基于EWT改进限流电抗电压的柔性直流配电网故障保护方法  

An improved fault protection method for a flexible DC distribution network based on EWT current limiting reactance voltage

作　　者：韦延方[1,2] 杨萍 杨湛晔 王鹏 王晓卫 WEI Yanfang;YANG Ping;YANG Zhanye;WANG Peng;WANG Xiaowei(School of Electrical Engineering and Automation,Henan Polytechnic University,Jiaozuo 454003,China;Henan Key Laboratory of Intelligent Detection and Control of Coal Mine Equipment,Henan Polytechnic University,Jiaozuo 454003,China;Hainan Green Energy and Environmental Engineering and Technology Research Institute,Haikou 570125,China;State Grid Henan Electric Power Company Scientific Research Institute,Zhengzhou 450052,China;School of Electrical Engineering,Xi’an University of Technology,Xi’an 710000,China)

机构地区：[1]河南理工大学电气工程与自动化学院,河南焦作454003 [2]河南省煤矿装备智能检测与控制重点实验室,河南焦作454003 [3]海南绿色能源与环境工程技术研究院,海南海口570125 [4]国网河南省电力公司电力科学研究院,河南郑州450052 [5]西安理工大学电气工程学院,陕西西安710000

出　　处：《电力系统保护与控制》2024年第23期22-32,共11页Power System Protection and Control

基　　金：国家自然科学基金项目资助(61703144);海南省自然科学基金项目资助(521RC1110)。

摘　　要：直流线路故障的快速可靠识别是柔性直流配电网稳定运行的关键技术。利用限流电抗器的边界条件特性,提出了一种基于经验小波变换(empirical wavelet transform, EWT)改进限流电抗电压的柔性直流配电网故障保护方法。首先,利用经验小波变换对直流线路电压进行高频分量提取,采用改进电压梯度算法作为启动判据。然后,针对不同故障下直流线路两侧限流电抗器的高频暂态电压的尖峰度不同,提出利用峭度算法识别区内、外故障的保护判据。最后,利用Teager能量算子,计算出正、负极线路的高频暂态电压的瞬时能量最大值之比,构成故障选极的判据。实验结果表明,该方法能够准确地区分故障极以及区内、外故障,对通信要求低,具有较好的抗干扰能力,在不同工况下均能够可靠工作,可较好地满足柔性直流配电网对保护的速动性与选择性要求。Fast and reliable identification of DC line faults is key to the stable operation of a flexible DC distribution network.Based on the characteristics of boundary conditions of a current-limiting reactor,an improved current-limiting reactance voltage fault protection method for such a network based on empirical wavelet transform(EWT)is proposed.First,EWT is used to extract the high-frequency component of the DC line voltage,and an improved voltage gradient algorithm is adopted as the starting criterion.Then,from the different peaks of the high frequency transient voltage of the current limiting reactor on both sides of the DC line,a protection criterion using a kurtosis algorithm to identify the internal and external fault is proposed.Finally,using the Teager energy operator,this paper calculates the ratio of the instantaneous energy maximum of the high-frequency transient voltage of the positive and negative pole lines.This forms the criterion for fault pole selection.The experimental results show that this method can accurately distinguish the fault pole and internal and external faults,has low communication requirements and good anti-interference ability.It can work reliably in different working conditions,and can better meet the speed and selectiveness requirements for protection of a flexible DC distribution network.

关 键 词：柔性直流配电网 故障识别 EWT 高频暂态电压 峭度 TEAGER能量算子 

分 类 号：TM721.1[电气工程—电力系统及自动化]