±800 kV直流线路故障过程中电磁耦合特性与保护研究  

Research on Electromagnetic Coupling Characteristics During Fault Process in ± 800 kV UHVDC Transmission Line and Its Protection Strategy

作　　者：周全[1] 别睿[2] 涂莉[2] 冯鸫[1] 樊友平[2] 

机构地区：[1]中国南方电网超高压输电公司检修试验中心,广东省广州市510663 [2]武汉大学电气工程学院,湖北省武汉市430072

出　　处：《电网技术》2014年第8期2133-2140,共8页Power System Technology

基　　金：国家自然科学基金项目(61074101);高等教育博士学科点专项科研基金(20090141120062)~~

摘　　要：为提高直流输电系统运行的可靠性,实现直流线路保护的有效动作,避免误动,必须对直流输电系统的电磁耦合特性进行研究。以云广特高压直流输电工程为研究对象,并参照其线路参数,建立了包含杆塔、输电线路、避雷器、绝缘子串闪络以及换流站内各种设备的仿真模型。采用EMTP,以雷击直流输电线路极导线、一极接地故障后对另一极的影响为具体算例进行仿真计算。对仿真结果进行分析,结果表明在故障情况下,对直流输电线路感应电压影响较明显的是土壤电阻率、极线间距与接地故障位置,而线路运行电压对感应电压的影响不大。比较研究了不同故障过电压仿真结果,对于雷击故障,可以用电压突变量的比值来确定故障极;对于接地故障,用分别对金属性接地和阻抗接地故障波进行小波变换分析的结果作为区分依据。最后,依据故障区分特性,提出了考虑电磁耦合的高压直流输电线路保护判据和保护整定方案,经过验证表明,所提出的保护判据可有效地区分输电线路故障。To improve the reliability of UHVDC transmission system operation and implement the action of protective relalyings for UHVDC transmission line and avoid their misoperation, it is necessary to research the electromagnetic coupling of UHVDC transmission system. Taking UHVDC transmission project from Yunnan to Guangdong as research objective and referring to its parameters, a simulation model, in which the tower, transmission line, lightning arrester, flashover characteristics of insulator string and various equipments in converter stations are included, is established. Based on EMTP, the influence of a pole conductor, which is earthed due to lightning stroke, on another pole conductor is taken as the case and simulated, and the analysis on simulation results shows that in the case of such a fault three factors, namely the soil resistivity, the spacing between polar conductors and the position where the earth fault occurs, obviously influences the induced voltage in UHVDC transmission system while the operating voltage of UHVDC transmission line does not influence on the induced obviously. Comparative research on simulation results of over-voltage caused by different faults is performed, for the fault caused by lightning stroke the faulty pole can be determined by the ratio of abruptly changed voltages of the two pole conductors; for the earth fault, the wavelet transform result of traveling wave due to metallic grounding fault and that due to impedance grounding fault are respectively used as the distinguishing criteria. Finally, based on the characteristics to distinguish the fault, the protection criteria for UHVDC transmission line, inwhich the electromagnetic coupling is taken into account, and the protection setting scheme are proposed, and their effectiveness is validated by simulation results.

关 键 词：电磁耦合 特高压直流输电 故障过电压 雷电故障 接地故障 线路保护 

分 类 号：TM773[电气工程—电力系统及自动化]