基于线性回归的柔性直流电网纵联保护方法  

Pilot Protection Method of Flexible DC Grid Based on Linear Regression

作　　者：束洪春[1,2] 代月 安娜[1,2] 唐玉涛 薄志谦 Shu Hongchun;Dai Yue;An Na;Tang Yutao;Bo Zhiqian(State Key Laboratory of Collaborative Innovation Center for Smart Grid Fault Detection Protection and Control Jointly Kunming University of Science and Technology,Kunming 650500 China;Faculty of Mechanical and Electrical Engineering Kunming University of Science and Technology,Kunming 650500 China)

机构地区：[1]省部共建智能电网故障检测与保护控制协同创新中心(昆明理工大学),昆明650500 [2]昆明理工大学机电工程学院,昆明650500

出　　处：《电工技术学报》2022年第13期3213-3226,3288,共15页Transactions of China Electrotechnical Society

基　　金：国家自然科学基金(52037003);云南省重大专项(202002AF080001)资助项目。

摘　　要：柔性直流电网线路发生故障时,线路保护装置需要快速可靠地切除故障线路以保证非故障线路能正常运行,进而提高输电系统的安全性和可靠性。为此提出柔性直流电网快速纵联保护的线性回归方法。首先分析模块化多电平换流器(MMC)等效阻抗和平波电抗器形成的物理边界对高频分量的衰减作用,其次分析输电线路单极故障和双极故障时的电流回路以及非故障线路的电流流通情况,然后根据输电线路的电压突变的能量作为保护的启动判据,利用短时窗电流的回归系数来进行区内外故障识别和故障选极;最后,在PSCAD上搭建柔性直流电网仿真模型对保护方案进行验证,仿真结果表明,该保护方法能准确可靠地甄别故障,速动性好,具有较好的耐过渡电阻能力和适用性。When a fault occurs in a flexible DC grid line, the line protection device needs to quickly and reliably remove the faulty line to ensure that the healthy line can operate normally to improve the safety and reliability of the transmission system. In this paper, a linear regression method for fast pilot protection of flexible DC grid is proposed. Firstly, the physical boundary formed by the modular multilevel converter(MMC) equivalent impedance and the smoothing reactor is analyzed for the attenuation of the high frequency components, and secondly, the current loop and the current flow of the healthy line are analyzed for the single-pole and double-pole faults of the transmission line, and then the regression coefficient of the short-time window current is used for the identification of faults inside and outside the area and the selection of the faulted pole according to the energy of the voltage mutation of the transmission line as the protection activation criterion. A simulation model of the flexible DC network is built on PSCAD to verify the protection scheme. The simulation results show that the protection method can reliably and accurately screen faults with good quick action, and has good transition resistance and applicability.

关 键 词：柔性直流电网 模块化多电平换流器物理边界 线性回归 故障检测 线路保护 

分 类 号：TM723[电气工程—电力系统及自动化]