基于采样值差动原理的低频输电线路差动保护研究  

Research on differential protection of low frequency transmission lines based on differential principle of sampling values

作　　者：潘武略 钱政旭 孙志攀 洪丰 曹文斌 王松 方愉冬 PAN Wulue;QIAN Zhengxu;SUN Zhipan;HONG Feng;CAO Wenbin;WANG Song;FANG Yudong(State Grid Zhejiang Electric Power Co.,Ltd.Research Institute,Hangzhou 310014,China;NARI Group Corporation,Nanjing 210000,China;Nanjing Control System Co.,Ltd.,NARI Technology Co.,Ltd.,Nanjing 210000,China)

机构地区：[1]国网浙江省电力有限公司电力科学研究院,杭州310014 [2]南瑞集团有限公司,南京210000 [3]国电南瑞南京控制系统有限公司,南京210000

出　　处：《浙江电力》2023年第2期35-42,共8页Zhejiang Electric Power

基　　金：国网浙江省电力有限公司科技项目(2021ZK07)。

摘　　要：低频输电线路发生区内故障时,因线路两端M3C(模块化多电平矩阵变换器)对故障电流幅值、相位的限制,使得两侧电流呈现穿越特性,进而造成传统基于相量的线路差动保护灵敏度降低甚至拒动。为解决上述问题,首先基于低频输电系统架构分析了线路故障后的电气特征及相量差动保护适应性;随后结合采样值差动原理,给出了3个基于采样值的逻辑判据,与稳态量差流门槛及低比率制动方程共同构成适用于低频输电线路的差动保护实现方法;最后在RTDS(实时数字仿真系统)中搭建了低频输电系统模型,通过对低频线路区内、区外不同类型故障的仿真分析,验证了该方法在低频输电线路中的有效性,为后续工程应用奠定了基础。As a fault occurs in a low-frequency transmission line zone, the modular multilevel matrix converters(M3Cs) at both ends of the line limit the fault current amplitude and phase. Under such a circumstance, the current on both sides displays the characteristics of through current, which in turn leads to poor sensitivity or even failure to operate of the traditional phase-based line differential protection. To solve the above problems, the electrical characteristics of the line after a fault and the adaptability of the phase differential protection are analyzed first based on the architecture of the low-frequency transmission system. Then three logical criteria based on the sampling values are given in combination with the differential principle of sampling values, which together with the steady-state differential threshold current and the low ratio braking equation constitute a differential protection method applicable to low-frequency transmission lines. Finally, a model of the low-frequency transmission system is built in RTDS(realtime digital simulation) system, and the effectiveness of the method used in low-frequency transmission lines is verified through the simulation analysis of different types of faults within and outside the lines, which lays the foundation for subsequent engineering applications.

关 键 词：低频输电 线路保护 差动保护 采样值差动 

分 类 号：TM773[电气工程—电力系统及自动化]