引用本文: | 邓祥力,陈兴霖.基于电流故障分量时频矩阵相角差的换流变差动保护研究[J].电力系统保护与控制,2021,49(23):44-53.[点击复制] |
DENG Xiangli,CHEN Xinglin.Converter transformer differential protection based on the phase angle difference of the time-frequency matrix of a current fault component[J].Power System Protection and Control,2021,49(23):44-53[点击复制] |
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摘要: |
传统换流变差动保护中易受直流偏磁和故障过渡电阻影响,可能出现差动保护的拒动问题。为此,提出一种基于电流故障分量(Current Fault Component, CFC)时频矩阵元素和相角判别的换流变差动保护判据。变压器发生区内故障时,变压器两侧电流互感器(CT)检测到的CFC方向相同,而区外故障时检测到的两侧CFC方向相反。通过S变换获得CFC时频矩阵,根据故障时刻时频矩阵内所有元素求和所得相量的相角大小,判别CFC的方向,从而实现换流变区内故障的识别。仿真结果表明,所提保护判据在各种故障情况下均可有效识别换流变的区内、区外故障,在直流偏磁和故障过渡电阻的情况下仍具有较高的可靠性,同时可有效降低差动保护误动风险。 |
关键词: 换流变压器 差动保护 时频矩阵 电流故障分量 S变换 |
DOI:DOI: 10.19783/j.cnki.pspc.210995 |
投稿时间:2021-08-01修订日期:2021-09-04 |
基金项目:国家自然科学基金项目资助(51777119) |
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Converter transformer differential protection based on the phase angle difference of the time-frequency matrix of a current fault component |
DENG Xiangli,CHEN Xinglin |
(College of Electrical Engineering, Shanghai University of Electric Power, Shanghai 200090, China) |
Abstract: |
Traditional converter transformer differential protection is easily affected by DC bias and fault transition resistance. These may cause the rejection of differential protection. Thus a criterion of converter transformer differential protection based on the time-frequency matrix elements and phase angle discrimination of a Current Fault Component (CFC) is proposed. In the case of an internal fault of the transformer, the CFC direction detected by Current Transformers (CT) on both sides of transformer is the same, while in case of an external fault, the CFC direction detected on both sides is opposite. The CFC time-frequency matrix is obtained by an S-transform. From the phase angle of the phasor obtained by summing all elements in the time-frequency matrix at the fault time, the direction of the CFC is distinguished, so as to realize the fault identification in the converter transformer region. The simulation results show that the proposed protection criterion can effectively identify the internal and external faults of the converter transformer under various fault conditions, and still has high reliability in the case of DC bias and fault transition resistance. At the same time, it can effectively reduce the misoperation risk of differential protection.
This work is supported by the National Natural Science Foundation of China (No. 51777119). |
Key words: converter transformer differential protection time-frequency matrix current fault component S-transform |