1.国家电网有限公司华中分部,湖北省武汉市 430077;2.柳焕章劳模创新工作室,湖北省武汉市 430077;3.华中科技大学电气与电子工程学院,湖北省武汉市 430074;4.强电磁工程与新技术国家重点实验室(华中科技大学),湖北省武汉市 430074
交流线路零序电流保护最末一段均采用300 A定值,存在无序跳闸风险。因此,文中提出了基于零序电抗线和非故障相极化的高阻接地距离继电器原理。继电器采用先选相、后测量的技术路线,选相元件将零序电抗线与非故障相极化方法相结合,构成多种组合判据,以分工完成选相。由于保护安装处零序电流与故障点零序电流存在相位差异,单相接地故障的故障相和相间接地故障的超前相的零序电抗线在故障点位于整定点附近时存在混叠区。区内近端、低阻单相接地故障时非故障相工作电压大幅变化,不利于区分混叠区的两类故障,故将选相元件分为低阻模块和高阻模块。低阻模块采用下偏的零序电抗线,用于识别近端、低阻故障;经低阻模块辅助后,高阻模块只需针对性处置故障点位于整定点附近的故障,可有效区分两类故障。选相完成后,通过非故障相极化的方法获得故障前工作电压,从而确定继电器的动作特性。高阻距离继电器的耐过渡电阻能力远超规程要求,提高了接地后备保护对高阻接地故障的选择性。
国家电网有限公司华中分部科技项目(521400230004);已申请国家发明专利(申请号:2024109442260)。
李勇(1981—),男,教授级高级工程师,主要研究方向:继电保护运行管理。E-mail:500ly@163.com
李银红(1976—),女,博士,研究员,主要研究方向:继电保护整定计算。E-mail:799758486@qq.com
柳焕章(1954—),男,高级工程师,主要研究方向:继电保护运行管理、整定计算、继电保护原理。E-mail:liuhz@cc.sgcc.com.cn
刘阳(1988—),男,通信作者,博士,高级工程师,主要研究方向:继电保护整定计算。E-mail:liuyangwuh520@sina.com
1.Central China Branch of State Grid Corporation of China, Wuhan 430077, China;2.Lamor Innovation Studio of Liu Huanzhang, Wuhan 430077, China;3.School of Electrical and Electronic Engineering, Huazhong University of Science and Technology, Wuhan 430074, China;4.State Key Laboratory of Advanced Electromagnetic Technology (Huazhong University of Science and Technology), Wuhan 430074, China
The last section of zero-sequence current protection of AC line adopts 300 A, which has the risk of disordered tripping.Therefore, a new principle of high-resistance grounding distance relay based on zero-sequence reactance line and non-fault phase polarization is proposed. The relay adopts the technical route of phase selection before measurement. The phase selection element combines zero-sequence reactance line and non-fault phase polarization method to form a variety of combined criteria to complete the phase selection. Due to the phase difference between the zero-sequence current at the protection installation site and the zero-sequence current at the fault point, the zero-sequence reactance lines of the single-phase grounding fault phase and the advance phase of the inter-phase grounding fault have aliasing region when the fault point is near the setting point. The large variation of the operation voltage of the non-fault phase is not conducive to distinguishing the two types of faults in the aliasing region, and thus the phase selection element is divided into low-resistance module and high-resistance module. The low-resistance module adopts the zero-sequence reactance line with the downward bias, which is used to identify the near end and low-resistance short circuit. With the assistance of the low-resistance module, the high-resistance module only needs to deal with the faults near the setting point, which reduces the difficulty in distinguishing the two types of faults. After phase selection, the operation voltage before fault is obtained by non-fault phase polarization method, so as to determine the operation characteristics of the relay. The ability of high-resistance distance relay to withstand the transition resistance is far beyond the requirements of the regulations, which improves the selectivity of grounding backup protection to high-resistance faults.
[1] | 李勇,李银红,柳焕章,等.基于高阻接地距离继电器的零序电流保护选择性提升方案[J].电力系统自动化,2024,48(21):169-179. DOI:10.7500/AEPS20240228008. LI Yong, LI Yinhong, LIU Huanzhang, et al. Selectivity Enhancement Scheme for Zero-sequence Current Protection Based on Distance Relay for High-resistance Grounding Fault[J]. Automation of Electric Power Systems, 2024, 48(21):169-179. DOI:10.7500/AEPS20240228008. |