{"title":"Adaptability Analysis and Improvement of Traditional Transformer Protection in Offshore Low-Frequency Wind Power System","authors":"Chenqing Wang, Shi Chen, Xinyu Wu, Yaming Ge, Xiangping Kong, Shuping Gao, Jinyu Zhou","doi":"10.1049/gtd2.70107","DOIUrl":null,"url":null,"abstract":"<p>Since both ends of the AC transmission and outlet lines of the offshore low-frequency transmission system are power electronic equipment, the current distortion during the fault process of the power grid may cause the adaptability of the existing protection to be reduced. The traditional ratiometric differential transformer protection method based on the second harmonic braking principle has a serious delay problem when the low-frequency operation system fails. How to improve the existing protection performance and solve the problem of protection adaptability under the offshore low-frequency wind power system is the core problem of this paper. In this paper, a zero-sequence differential protection based on phase difference is proposed for the internal grounding fault of the transformer, which has strong anti-excitation inrush current interference, and the protection criterion is the self-generated zero-sequence current and the neutral point zero-sequence current on the high-voltage side of the transformer. However, since there is no zero sequence current in the case of interphase fault, a transformer protection based on the phase difference of the negative sequence current is proposed. The offshore low-frequency wind power transmission system was built by PSCAD, and the feasibility of the protection algorithm was verified by MATLAB. The simulation results show that the proposed protection principle operates quickly and reliably no matter any fault occurs in the low-frequency transformer.</p>","PeriodicalId":13261,"journal":{"name":"Iet Generation Transmission & Distribution","volume":"19 1","pages":""},"PeriodicalIF":2.6000,"publicationDate":"2025-06-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1049/gtd2.70107","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Iet Generation Transmission & Distribution","FirstCategoryId":"5","ListUrlMain":"https://ietresearch.onlinelibrary.wiley.com/doi/10.1049/gtd2.70107","RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"ENGINEERING, ELECTRICAL & ELECTRONIC","Score":null,"Total":0}
引用次数: 0
Abstract
Since both ends of the AC transmission and outlet lines of the offshore low-frequency transmission system are power electronic equipment, the current distortion during the fault process of the power grid may cause the adaptability of the existing protection to be reduced. The traditional ratiometric differential transformer protection method based on the second harmonic braking principle has a serious delay problem when the low-frequency operation system fails. How to improve the existing protection performance and solve the problem of protection adaptability under the offshore low-frequency wind power system is the core problem of this paper. In this paper, a zero-sequence differential protection based on phase difference is proposed for the internal grounding fault of the transformer, which has strong anti-excitation inrush current interference, and the protection criterion is the self-generated zero-sequence current and the neutral point zero-sequence current on the high-voltage side of the transformer. However, since there is no zero sequence current in the case of interphase fault, a transformer protection based on the phase difference of the negative sequence current is proposed. The offshore low-frequency wind power transmission system was built by PSCAD, and the feasibility of the protection algorithm was verified by MATLAB. The simulation results show that the proposed protection principle operates quickly and reliably no matter any fault occurs in the low-frequency transformer.
期刊介绍:
IET Generation, Transmission & Distribution is intended as a forum for the publication and discussion of current practice and future developments in electric power generation, transmission and distribution. Practical papers in which examples of good present practice can be described and disseminated are particularly sought. Papers of high technical merit relying on mathematical arguments and computation will be considered, but authors are asked to relegate, as far as possible, the details of analysis to an appendix.
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Design of transmission and distribution systems
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Power system management, planning and economics
Power system operation, protection and control
Power system measurement and modelling
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