链式STATCOM并网电流直流分量间接闭环抑制  

Indirect Closed-loop DC Current Suppression for Cascaded STATCOM

作　　者：周启文[1] 魏星[1] 王鹏飞 王辉 李钊[1] 朱信舜[1] ZHOU Qiwen;WEI Xing;WANG Pengfei;WANG Hui;LI Zhao;ZHU Xinshun(NR Electric Co.,Ltd.,Nanjing 211102,China)

机构地区：[1]南京南瑞继保电气有限公司,南京211102

出　　处：《高电压技术》2022年第8期3146-3154,共9页High Voltage Engineering

基　　金：南瑞集团有限公司科技项目(JS2001707)。

摘　　要：当中高压应用场合的链式静止同步补偿器使用电流互感器采集并控制并网电流时,电流互感器的隔直效应将进一步放大驱动参数和特性差异以及采样零漂引起的直流分量,危害电网及设备安全。因此,提出一种基于直流侧电容电压工频分量检测的并网电流直流分量闭环抑制策略,其无需增加额外元件且不改变原有控制架构。首先分析了并网电流直流分量与直流侧电容电压之间的关系,再通过频谱搬移和滑动平均值滤波提取直流侧电容电压的工频分量,然后经闭环控制后叠加至调制波上实现间接抑制,最后在一套使用电流互感器采样控制的工程应用的10 kV/±10 MVA星型链式STATCOM设备上验证了该策略的可行性和有效性。实验结果表明,该方法能够在无法直接检测直流分量的条件下,有效地将并网电流的直流分量由49.80%抑制到0.72%。When current transformer(CT)is adopted to sample grid-connected currents and to control the closed-loop currents in the cascaded static synchronous compensator(STATCOM)in medium and high voltage applications,the isolated DC current effect of CT will further amplify the DC current caused by the difference of driving parameters and characteristics and sampling zero drift,which endanger the safety of power grids and equipment.This paper proposes an indirect closed-loop DC component suppression strategy for grid-connected current based on extracting the power frequency component of the DC capacitor voltage,without adding additional components and without changing the original control architecture.First,the relationship between the DC component of the grid-connected current and the DC capacitor voltage is analyzed,then the power frequency component of the DC capacitor voltage is extracted through spectrum shift and moving average filtering,and then is superimposed on the modulation wave after closed-loop control to achieve indirect suppression.Finally,the feasibility and effectiveness of this strategy are verified on a set of 10 k V/±10 MVA star-connected cascaded STATCOM equipment for engineering applications using current transformer sampling control.The experimental results show that the method can be used in applications where the DC component cannot be directly detected.Under these conditions,the DC component of the grid-connected current is effectively suppressed from 49.80%to 0.72%.

关 键 词：链式静止同步补偿器 直流分量 电流互感器 间接闭环抑制 直流侧电容电压工频分量 

分 类 号：TM761.12[电气工程—电力系统及自动化]