摘要
多端直流电网是克服目前直流输电缺陷的新兴技术。随着直流断路器的工程化应用,对线路故障能实现快速准确辨识的超高速保护成为研究热点。但是,目前广泛研究的就地化保护属于边界保护,存在对系统一次结构适应性不高、无法良好兼顾可靠性与灵敏性等问题;传统纵联保护受制于通信容量及传播延时,难以担当主保护功能。针对以上问题,该文在充分分析直流电网故障后线模行波复杂折反射特性的基础上,利用行波在保护安装处的折/反射比值关系,提出一种无需大量数据交换及严格同步对时,即可覆盖线路全长、且拥有高灵敏性的允许式纵联保护原理;考虑环网等特殊拓扑结构,构造基于上述比值关系的保护判据,确保保护原理的高可靠性;以换流器关断时间为基准整定保护窗口,定量地得出保障保护速动性的适用线路长度范围。最后,对所提出的保护原理进行算例分析及对比验证。
VSC-MTDC is a new technology that can overcome the shortcomings of current DC transmission technologies.With the engineering application of DC circuit breaker,ultra-high-speed protection,which can quickly and accurately identify line faults,has become a research hotspot.However,the single-ended protection which is widely studied at present belongs to the type of boundary protection.It has some problems,such as low adaptability to primary structure of the system,inability to coordinate the reliability and the sensitivity,etc.The traditional pilot protection is limited by communication capacity and time delay,and it is difficult to be used as a type of main protection.In view of the above problems,based on the analysis of the complex refraction/reflection characteristics of the traveling wave after the DC grid fault,the refraction/reflection ratio was used to establish the protection criterion.The criterion can cover the whole line with high sensitivity.Considering the special topological structure such as loop network,a locking criterion based on the above ratio relationship was constructed to ensure the high reliability of the protection principle.According to the switch-off time of the converter,the suitable line length range to ensure the protection fast-tripping capability was obtained quantitatively.Finally,the proposed protection principle was analyzed and verified by simulation cases.
作者
魏霖
童宁
林湘宁
随权
陈乐
胡仙清
金能
李正天
WEI Lin;TONG Ning;LIN Xiangning;SUI Quan;CHEN Le;HU Xianqing;JIN Neng;LI Zhengtian(Electric Engineering&Renewable Energy School,China Three Gorges University,Yichang 443002,Hubei Province,China;State Key Laboratory of Advanced Electromagnetic Engineering and Technology(Huazhong University of Science and Technology),Wuhan 430074,Hubei Province,China)
出处
《中国电机工程学报》
EI
CSCD
北大核心
2019年第S01期95-108,共14页
Proceedings of the CSEE
基金
国家电网公司科技项目(5100-201999331A-0-0-00)
中国博士后科学基金项目(2018M642838).
关键词
直流电网
边界元件
纵联保护
换流器
DC grid
boundary component
pilot protection
converter
作者简介
魏霖(1994),男,硕士研究生,研究方向为继电保护、直流输电,495316861@qq.com;通信作者:童宁(1988),男,博士后,工程师,研究方向为继电保护、高压直流输电等,tony1109@qq.com;
