摘要
现有交流线路保护仍基于同步机电源特性,随着新能源占比不断提升、电力电子化特征更加明显,其适应边界将逐渐减小,有必要研究不依赖电源特性的继电保护新原理。文中提出了利用行波波前故障信息实现高性能保护的原理。首先,推导了交流线路故障行波波前解析表达式,指出行波波前表达式包含工频正弦项和直流衰减项。直流衰减项的指数系数仅受故障距离影响,而两代数项的幅值系数与故障严重程度有关,由此实现了行波波前故障距离、故障严重程度信息的表征与解耦。进一步,提出了基于多点消去的波前指数系数提取算法,实现了波前故障距离信息的有效提取。在此基础上,提出了交流输电线路单端量波前保护新原理,分析了串联/并联/组合型线路边界对波前指数系数的影响。仿真验证结果表明,保护能够快速、可靠、灵敏地识别交流输电线路故障,不受故障类型和过渡电阻的影响,适用于不同的新能源及电力电子装备接入场景,且运算量小,受噪声影响小。
The existing AC line protection methods are still based on the characteristics of synchronous generator.As the proportion of renewable energy continues to increase and the characteristics of power electronics become more obvious,its adaptation boundary will gradually decrease.It is necessary to study new principles of relay protection that are independent of power source characteristics.The principle of using traveling wavefront fault information to achieve high-performance protection is proposed.Firstly,an analytical expression for the traveling wavefront of AC line faults is derived,indicating that the traveling wavefront expression includes the power frequency sine term and the DC attenuation term.The exponential coefficient of the DC attenuation term is only affected by the fault distance,while the amplitude coefficients of the two algebraic terms are related to the severity of the fault.Thereby the representation and decoupling of fault distance and fault severity information are realized.A wavefront exponential coefficient extraction algorithm based on the multi-point elimination is further proposed,achieving effective extraction of wavefront fault distance information.On this basis,a new principle of single-ended wavefront protection for AC transmission lines is proposed,and the influence of series/parallel/combination line boundaries on the wavefront exponential coefficient is analyzed.The simulation results show that the protection can quickly,reliably,and sensitively identify AC transmission line faults,without being affected by fault types and transition resistors.It is suitable for different scenarios of renewable energy and power electronic equipment integration,and has low computational complexity and is less affected by noise.
作者
张晨浩
闫吉飞
吕艺超
宋国兵
郑玉平
吴通华
ZHANG Chenhao;YAN Jifei;LYU Yichao;SONG Guobing;ZHENG Yuping;WU Tonghua(School of Electric Engineering,Xi'an Jiaotong University,Xi'an 710049,China;NARI Group Corporation(State Grid Electric Power Research Institute),Nanjing 211106,China)
出处
《电力系统自动化》
EI
CSCD
北大核心
2023年第22期33-43,共11页
Automation of Electric Power Systems
基金
国家自然科学基金青年基金资助项目(52207136)
国家电网有限公司科技项目(新型电力系统继电保护体系架构与关键技术研究,5108-202240278A-2-0-XG)。
关键词
交流输电线路
线路保护
单端量保护
电源特性
行波
AC transmission line
line protection
single-ended protection
power source characteristic
traveling wave
