基于罗氏线圈电流互感器的等传变距离保护  

Distance Relay Based on Rogowski Coil Current Transformer by Using Instantaneous Value after Equal Transfer Processes

作　　者：李宝伟[1,2] 石欣 王志伟 文明浩 张旭[2] Li Baowei;Shi Xin;Wang Zhiwei;Wen Minghao;Zhang Xu(State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology,Wuhan 430074,China;XJ Electric Co.Ltd,Xuchang 461000,China)

机构地区：[1]强电磁工程与新技术国家重点实验室(华中科技大学),武汉430074 [2]许继电气股份有限公司,许昌461000

出　　处：《电工技术学报》2023年第5期1353-1362,共10页Transactions of China Electrotechnical Society

基　　金：国家自然科学基金项目(51877090);国家电网有限公司总部科技项目(4000-202222070A-1-1-ZN)资助。

摘　　要：罗氏线圈电流互感器中的积分器会放大暂态传变误差,可能导致保护误动作。该文提出直接采用罗氏线圈微分信号输出进行保护计算的改进思路,并以距离保护为例,提出一种基于罗氏线圈电流互感器的等传变距离保护方法。该方法中,保护电流直接采用罗氏线圈输出的电流微分信号,消除积分器引入的暂态传变误差,并通过虚拟数字传变解决电压与电流微分信号传变不一致问题。仿真和试验结果表明,所提出的等传变距离保护方法动作速度快,受系统中高频暂态信号影响较小,性能优于现有距离保护方法。Since the output voltage of the coil is proportional to the rate of change of the primary current,it is required to be integrated to recover the measured current,which is usually realized by electronic integrator circuits.High-frequency transient signals tend to be generated during power system operation or short-circuit faults.After being processed by the integrator,the output signal of electronic transformer may be seriously distorted,resulting in mal-operation of the relay.Many researchers have proposed a variety of detection methods for abnormal output of the Rogowski coil,but the impact of additional components caused by integrators on protection cannot be avoided.An improved method of line relay directly using the differential output of Rogowski coil is put forward.Besides,a distance relay based on Rogowski coil current transformer by using instantaneous value after equal transfer processes is proposed.In the novel scheme,the current differential signal output by Rogowski coil is directly used to eliminate the influence of transient transmission error introduced by integrator.Firstly,according to the equal transfer process of transmission lines(ETPTL)theory,the virtual Rogowski coil digital transmission link is constructed to process the voltage signal with the same transmission characteristics as the Rogowski coil digital transmission link,so that the voltage and current signals used for distance protection pass through the same transmission link.Secondly,the R-L equations are solved by least square method to calculate the fault location,so as to improve the stability of the calculation results.Thirdly,the voltage at the fault point is reconstructed and passed through the digital transmission link of virtual Rogowski coil to make it have the same transient transmission process as the voltage at the protection installation,so as to reduce the initial calculation error of fault and accelerate the convergence of fault calculation to stability.Finally,a method of model error discrimination is proposed.Accordin

关 键 词：罗氏线圈 积分器 距离保护 虚拟罗氏线圈 等传变 

分 类 号：TM773[电气工程—电力系统及自动化]