摘要
为解决电流互感器(CT)发生饱和时其二次电流畸变进而导致母线差动保护误动的问题,提出一种电流互感器饱和识别及有效数据提取方案。首先基于采样信息时频特性的相似性将连接于同一母线的CT划分为一组,然后在保护启动后采用优化小波包算法识别组内所有CT采样电流的突变点,通过对比识别CT饱和,同时提取故障发生后的有效数据段,根据其长度采用不同的滤波算法进行保护计算。基于PSCAD的仿真表明所提方案能够准确识别各种不同类型的CT饱和,对于快速饱和、干扰以及转换性故障也能有效应对。
In order to solve the busbar differential protection maloperation caused by the secondary side current distortion when saturation of current transformer occurs,a novel strategy of the current transformer saturation identification and valid data extraction is proposed in this paper.Current transformers connected to the same busbar within a substation were grouped based on the similarity of sampling information time-frequency characteristics in the first place.Then,an optimized wavelet packet algorithm was used to identify the mutation points of all the secondary currents in the same group.By comparing each mutation point of secondary current within the same group,whether current transformer saturation occurred could be determined,and the valid data segment after fault occurred was extracted for protection calculation.According to the length of different valid data,different protection algorithms were applied to determine the fault types.Simulation results based on PSCAD verify that the proposed method can locate all the mutation points of the secondary current and identify different kinds of current transformer saturation accurately.Furthermore,the proposed method can effectively deal with fast saturation,interference,and transferring fault.
作者
邢家维
金能
林湘宁
刘尧
李贞
Xing Jiawei;Jin Neng;Lin Xiangning;Liu Yao;Li Zhen(State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology,Wuhan 430074 China;China-EU Institute for Clean and Renewable Energy Huazhong University of Science and Technology,Wuhan 430074 China;XJ Electric Corporation Limited,Xuchang 461000 China)
出处
《电工技术学报》
EI
CSCD
北大核心
2019年第6期1170-1179,共10页
Transactions of China Electrotechnical Society
基金
国家自然科学基金(51577077
51477090)
国家电网公司科技项目(SGTYHT/16-JS-198)
关键词
电流互感器饱和
小波包理论
有效数据段
小矢量算法
相关分析
Current transformer saturation
wavelet packet
valid data segment
phaselet algorithm
correlation analysis