基于模型校核的静止变频器采样值差动保护原理  

Principle of sampled value differential protection of static frequency converters based on model verification

作　　者：张大海[1] 李宇欣 李猛 刚玉阳 周健 李小鹏 ZHANG Dahai;LI Yuxin;LI Meng;GANG Yuyang;ZHOU Jian;LI Xiaopeng(School of Electrical Engineering,Beijing Jiaotong University,Beijing 100044,China;Pumped-storage Technological&Economic Research Institute,State Grid Xinyuan Company Ltd.,Beijing 100761,China;State Grid Sichuan Electric Power Research Institute,Chengdu 610041,China)

机构地区：[1]北京交通大学电气工程学院,北京100044 [2]国网新源控股有限公司抽水蓄能技术经济研究院,北京100761 [3]国网四川省电力公司电力科学研究院,四川成都610041

出　　处：《电力系统保护与控制》2025年第4期27-36,共10页Power System Protection and Control

基　　金：国家电网有限公司科技项目资助(5419-202243074A-1-1-ZN)。

摘　　要：静止变频器(static frequency converter,SFC)是抽水蓄能电站大型同步机组启动过程的重要设备。在抽蓄机组启动的过程中,由于SFC机、网两侧电流频率不一致,使得基于工频相量的常规差动保护配置困难,且现有保护方案在速动性和可靠性上存在不足。为解决上述问题,提出了一种基于模型校核的SFC采样值差动保护原理。首先充分研究SFC的工作原理和控制策略,并基于电流采样值在时域内构建符合SFC工作原理的数学模型,然后采用模型校核的方法寻找故障前后差异并提出相应的保护判据。最后,在PSCAD/EMTDC中搭建抽蓄机组SFC启动的电磁暂态仿真模型,验证所提保护原理的有效性。仿真结果表明,所提保护原理不受SFC两侧不同频率的干扰,具有良好的选择性、速动性和可靠性。Static frequency converter(SFC)is an important piece of equipment for the startup process of large synchronous units in pumped storage power plants.In the process of startup,the different current frequencies on both sides of the SFC make it difficult to configure the conventional differential protection based on power frequency phasors.Additionally,the existing protection schemes have deficiencies in terms of speed and reliability.To address these problems,this paper proposes a sampled value differential protection principle for an SFC based on model verification.First,the operating principles and control strategies of an SFC are thoroughly studied,and a mathematical model that aligns with the SFC’s working principles is constructed in the time domain using current sampled values.Then,a model verification method is applied to identify differences before and after a fault,and the corresponding protection criteria are established.Finally,an electromagnetic transient simulation model of the pumped storage unit’s SFC startup is built in PSCAD/EMTDC to verify the effectiveness of the protection principle.Results show that the proposed protection principle is not affected by the frequency differences on both sides of the SFC,and exhibits excellent selectivity,fast response,and reliability.

关 键 词：抽水蓄能 静止变频器 模型校核 电流采样值 差动保护 

分 类 号：TV743[水利工程—水利水电工程] TM773[电气工程—电力系统及自动化]