考虑逆变器接口电站的线路电流差动保护分析及对策  

Analysis of the line current differential protection considering inverter-interfaced generation station and countermeasures

作　　者：马凯琪 王砚帛 陈哲[1] MA Kaiqi;WANG Yanbo;CHEN Zhe(Department of Energy Technology,Aalborg University,Aalborg 9220,Denmark)

机构地区：[1]丹麦奥尔堡大学能源技术系,丹麦奥尔堡9220

出　　处：《长江大学学报（自然科学版）》2022年第1期110-117,共8页Journal of Yangtze University(Natural Science Edition)

基　　金：ForsKEL and EUDP project“Voltage control and protection for a grid towards 100%power electronics and cable network(COPE)”(880063).

摘　　要：近年来,可再生能源在输电系统中的渗透明显增加,这给现有的保护系统带来了重大挑战。主要研究了与逆变器接口电站(ⅡGS)相连的电网中的线路电流差动保护问题,结合逆变器接口发电机(ⅡG)中流行的各种故障控制策略以及ⅡGS的穿透水平,提出了针对不对称故障下的解耦序分量(DSC)控制方法。与传统的非解耦的控制方式相比,DSC方法能有效消除有功输出和有直流电压连接的线路中的二次谐波振动,同时,DSC方法能模仿同步发电机的故障行为,提高系统电压稳定和继电保护适应性。最后,基于DIgSILENT/PowerFactory进行了仿真验证。仿真结果表明,在一定的ⅡG故障控制模式下,电流差动保护在不接地的相间故障时存在灵敏度较弱甚至故障的风险。但采用DSC方法控制能有效提高电流差动保护的灵敏性。Recently,the penetration of renewable energies in the transmission system has increased evidently,and this brings significant challenges for the existing protection systems.This paper focused on the line current differential protection in the power networks connecting to the inverter-interfaced generation station(ⅡGS).Combining the various fault control strategies popular in the inverter-interfaced generator(ⅡG),as well as theⅡGS penetration level,the decoupled sequencecontrol(DSC)scheme was developed during asymmetrical grid faults.Compared with the conventional non-decoupled control scheme,DSC is effective to eliminate the influence of second harmonic oscillations in the active power output and the DC-link voltage,meanwhile,the DSC is capable of emulating the fault behavior of SG,improving the system voltage stability and protection adaptability.Simulation verification based on the DIgSILENT/PowerFactory was carried out.Simulation results show that the current differential protection is in risk of weak sensitivity(or even malfunction)during non-grounded interphase faults under certainⅡG fault control modes,but the sensitivity of line current differential protection can be improved by using DSC scheme.

关 键 词：逆变器接口电站 线路电流差动保护 故障控制 负序控制 

分 类 号：TM773[电气工程—电力系统及自动化]