特高压串补线路中性点小电抗工作条件研究  

Research on Neutral Reactor Working Condition of UHV Lines With Series Capacitors

作　　者：郑彬 毕天姝 班连庚[2] 项祖涛[2] 马其燕[2] 杨大业[2] 杜宁[2] 

机构地区：[1]新能源电力系统国家重点实验室(华北电力大学),北京市昌平区102206 [2]中国电力科学研究院,北京市海淀区100192

出　　处：《电网技术》2017年第3期872-880,共9页Power System Technology

基　　金：国家电网公司科技项目(SGNX0000DKJS1500066)~~

摘　　要：特高压串补线路发生单相故障后,在串补电容器残压及其放电电流作用下,高抗中性点小电抗的电气应力特性与无串补线路发生变化。远距离特高压线路有加装更高补偿度串补的需求,使得串补线路的中性点小电抗过电压、过电流幅值可能超过现有小电抗设备的设计参数,有必要深入研究并提出有效对策。高幅值的低频振荡电流流经高抗可能致其饱和,使得中性点小电抗电气应力与将高抗视作线性元件时存在差别,目前尚未开展过相关研究。探讨了串补对特高压线路高抗中性点小电抗过电压、过电流问题的影响机理,基于典型系统条件仿真研究了提高串补度、高抗饱和对中性点小电抗过电压、过电流的影响特性,分析了联动旁路措施的抑制效果,并提出了解决小电抗电气应力超过现有设计参数问题的对策建议。研究成果可为特高压串补线路的工程设计、小电抗设备选型提供技术支撑。UHV transmission line with series capacitors（SC） can bring change to neutral reactors overvoltage and overcurrent characteristics compared to line without SC because of residual voltage and discharge current of series capacitor after line single phase fault. Long distance UHV lines have need to elevate series compensation degree, thus possibly leading to neutral reactor overvoltage and overcurrent higher than design parameters of present UHV neutral reactors, making further research necessary. High-amplitude low-frequency oscillation current flowing through shunt reactor may cause its saturation before bypassing the SC, making electric stress of neutral reactor different from that regarding the shunt reactor as linear element. Present research rarely involves this issue. This paper analyzes the influencing mechanism by SC on neutral reactors overvoltage and overcurrent of UHV line shunt reactors. Based on typical system conditions, influence characteristics of shunt reactor saturation and rising SC compensation degree on neutral reactors overvoltage and overcurrent are simulated. Inhibitory effect of linkage bypass measure is analyzed, and suggestions for technical parameters requirement of neutral reactors adapting to SC installation on UHV lines are put forward. Research results can provide technical support for engineering design and neutral reactor equipment selection of UHV lines with high series compensation degree.

关 键 词：特高压 串补 高补偿度 高抗饱和 中性点小电抗 工作条件 

分 类 号：TM76[电气工程—电力系统及自动化]