Performance Analysis of Converter Transformer Differential Protection under Valve-Side Winding Single-Phase Grounding and Improvement Scheme

IF 1.6 4区 工程技术 Q3 ENGINEERING, ELECTRICAL & ELECTRONIC
Yanxia Zhang, Le Wei, Hao Li, Ziyang Zhang
{"title":"Performance Analysis of Converter Transformer Differential Protection under Valve-Side Winding Single-Phase Grounding and Improvement Scheme","authors":"Yanxia Zhang, Le Wei, Hao Li, Ziyang Zhang","doi":"10.1007/s42835-024-01969-7","DOIUrl":null,"url":null,"abstract":"<p>This paper studies firstly the fault analysis method of valve-side winding single-phase grounding of converter transformer in line-commutated-converter high-voltage direct-current system. One power frequency cycle after fault is divided into 12 time periods according to the valve state, then the 12 time periods of high-voltage bridge faults are classified into 6 types based on the common characteristics, and the 12 time periods of low-voltage (LV) bridge faults are classified into 3 types. For each type of time period, the current flow path is analyzed, the corresponding circuit equation is written. By combining multiple time periods, the expressions of valve-side current and grid-side current are solved. On this basis, the differential current of converter transformer differential protection is derived and the performance of differential protection under valve-side winding single-phase grounding is studied. The research results show that when a single-phase grounding fault occurs in the valve-side winding of the LV bridge converter transformer, the second-harmonic ratio in the differential current is bigger than 15%, so the differential protection refuses to act due to mis-locking. In order to prevent differential protection from failing to act, an improved scheme of converter transformer differential protection is proposed. Through the logic coordination between the zero-sequence current unit and differential protection, the improved scheme can not only reflect various internal faults of converter transformer, but also ensure no action under the inrush current. The effectiveness of the proposed scheme is verified by simulation.</p>","PeriodicalId":15577,"journal":{"name":"Journal of Electrical Engineering & Technology","volume":"42 1","pages":""},"PeriodicalIF":1.6000,"publicationDate":"2024-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Electrical Engineering & Technology","FirstCategoryId":"5","ListUrlMain":"https://doi.org/10.1007/s42835-024-01969-7","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

This paper studies firstly the fault analysis method of valve-side winding single-phase grounding of converter transformer in line-commutated-converter high-voltage direct-current system. One power frequency cycle after fault is divided into 12 time periods according to the valve state, then the 12 time periods of high-voltage bridge faults are classified into 6 types based on the common characteristics, and the 12 time periods of low-voltage (LV) bridge faults are classified into 3 types. For each type of time period, the current flow path is analyzed, the corresponding circuit equation is written. By combining multiple time periods, the expressions of valve-side current and grid-side current are solved. On this basis, the differential current of converter transformer differential protection is derived and the performance of differential protection under valve-side winding single-phase grounding is studied. The research results show that when a single-phase grounding fault occurs in the valve-side winding of the LV bridge converter transformer, the second-harmonic ratio in the differential current is bigger than 15%, so the differential protection refuses to act due to mis-locking. In order to prevent differential protection from failing to act, an improved scheme of converter transformer differential protection is proposed. Through the logic coordination between the zero-sequence current unit and differential protection, the improved scheme can not only reflect various internal faults of converter transformer, but also ensure no action under the inrush current. The effectiveness of the proposed scheme is verified by simulation.

Abstract Image

阀侧绕组单相接地和改进方案下变流器变压器差动保护的性能分析
本文首先研究了线路换流式高压直流系统中换流变压器阀侧绕组单相接地的故障分析方法。根据阀状态将故障后的一个工频周期划分为 12 个时间段,然后根据共同特征将高压桥故障的 12 个时间段划分为 6 种类型,将低压(LV)桥故障的 12 个时间段划分为 3 种类型。针对每种类型的时间段,分析电流流动路径,并写出相应的电路方程。结合多个时间段,求解阀侧电流和电网侧电流的表达式。在此基础上,推导出变流器变压器差动保护的差动电流,并研究了阀侧绕组单相接地时差动保护的性能。研究结果表明,当低压桥式换流变压器阀侧绕组发生单相接地故障时,差动电流中的二次谐波比大于 15%,差动保护会因误动作而拒动。为了防止差动保护不动作,提出了一种改进的换流变压器差动保护方案。通过零序电流单元与差动保护之间的逻辑协调,改进后的方案不仅能反映变流器变压器的各种内部故障,还能确保在冲击电流下不动作。仿真验证了所提方案的有效性。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
求助全文
约1分钟内获得全文 求助全文
来源期刊
Journal of Electrical Engineering & Technology
Journal of Electrical Engineering & Technology ENGINEERING, ELECTRICAL & ELECTRONIC-
CiteScore
4.00
自引率
15.80%
发文量
321
审稿时长
3.8 months
期刊介绍: ournal of Electrical Engineering and Technology (JEET), which is the official publication of the Korean Institute of Electrical Engineers (KIEE) being published bimonthly, released the first issue in March 2006.The journal is open to submission from scholars and experts in the wide areas of electrical engineering technologies. The scope of the journal includes all issues in the field of Electrical Engineering and Technology. Included are techniques for electrical power engineering, electrical machinery and energy conversion systems, electrophysics and applications, information and controls.
×
引用
GB/T 7714-2015
复制
MLA
复制
APA
复制
导出至
BibTeX EndNote RefMan NoteFirst NoteExpress
×
提示
您的信息不完整,为了账户安全,请先补充。
现在去补充
×
提示
您因"违规操作"
具体请查看互助需知
我知道了
×
提示
确定
请完成安全验证×
copy
已复制链接
快去分享给好友吧!
我知道了
右上角分享
点击右上角分享
0
联系我们:info@booksci.cn Book学术提供免费学术资源搜索服务,方便国内外学者检索中英文文献。致力于提供最便捷和优质的服务体验。 Copyright © 2023 布克学术 All rights reserved.
京ICP备2023020795号-1
ghs 京公网安备 11010802042870号
Book学术文献互助
Book学术文献互助群
群 号:481959085
Book学术官方微信