弱交流电网下含STATCOM的LCC-HVDC系统的附加阻尼协调控制方法  

A Supplementary Damping Coordination Control for LCC-HVDC System With STATCOM Under Weak AC Grid Conditions

作　　者：郭春义[1] 蒋雯[1] 殷子寒 赵成勇[1] GUO Chunyi;JIANG Wen;YIN Zihan;ZHAO Chengyong(State Key Laboratory for Alternate Electrical Power System with Renewable Energy Sources（North China Electric Power University）,Changping District,Beijing 102206,China)

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)

出　　处：《中国电机工程学报》2018年第20期5957-5964,共8页Proceedings of the CSEE

基　　金：国家自然科学基金项目(51507060)~~

摘　　要：通过在电网换相换流器高压直流输电（line commutated converter based high voltage direct current,LCC-HVDC）逆变侧交流母线装设静止同步补偿器（static synchronous compensator,STATCOM）,来达到抑制换相失败的目的。然而研究发现,在弱交流系统工况下,STATCOM的控制系统（特别是交流电压控制外环）与LCC锁相环之间存在相互作用,会对后者的稳定可行域造成不利影响,进而可能引发整个混合系统的小干扰失稳现象。针对此现象,该文提出一种适用于弱交流系统下含STATCOM的LCC-HVDC系统的新型附加阻尼协调控制（supplementarydampingcoordination control,SDCC）,该方法基于LCC锁相环输出频率信息,引入阻尼系数以附加分量形式反馈到STATCOM定交流电压控制器外环输入中。基于Matlab的特征根理论分析及基于PSCAD/EMTDC的详细电磁暂态仿真结果表明,提出的SDCC控制可以有效抑制含STATCOM的LCC-HVDC系统中LCC锁相环增益过大引起的系统小干扰失稳现象,从而提高系统的稳定裕度。Static Synchronous Compensator （STATCOM） is utilized at the inverter bus of the line-commutated-converter based high voltage direct current （LCC-HVDC） system to mitigate the commutation failure （CF）. However, it is found that under weak AC systems, the control system of STATCOM （AC voltage controller in particularly） will interact with PLL of LCC system, which imposes an adverse effect on the whole system stability, and might even lead to oscillation owing to larger PLL gain of LCC system. This paper proposed a novel control approach i.e., supplementary damping coordination control （SDCC）, for LCC-HVDC system with STATCOM under weak AC grid conditions. Based on the tracked frequency from PLL of LCC system, the SDCC approach introduces a damping coefficient and generates an additional component to the input of AC voltage controller of STATCOM. The results from the eigenvalue analysis in Matlab and time-domain responses from PSCAD/EMTDC indicate that the SDCC approach can suppress the system instability due to the larger PLL gain of LCC system effectively, and thus improve the stability margin of the whole hybrid system.

关 键 词：电网换相换流器高压直流输电 锁相环 静止同步补偿器 小干扰稳定性 附加阻尼协调控制 弱交流电网 

分 类 号：TM73[电气工程—电力系统及自动化]