专用于抑制次同步振荡的STATCOM控制策略研究  

Research on a Dedicated Control Strategy for STATCOM to Suppress Subsynchronous Oscillation

作　　者：陈炜[1] 王翀[1] 王凯[1] 朱信舜[1] 

机构地区：[1]南京南瑞继保电气有限公司,江苏南京211102

出　　处：《电力电子技术》2017年第7期100-104,共5页Power Electronics

基　　金：国家电网公司科技项目(5222AS15000C)~~

摘　　要：针对汽轮发电机组接入串补输电系统的次同步振荡(SSO)和轴系扭振问题,提出在机组电网侧安装角型链式静止无功补偿器(STATCOM),并采用专用于抑制SSO的控制策略。在上层控制策略中,设计一种窄带次同步阻尼控制器,以转速偏差信号为输入,经过多组带通滤波器,实现了扭振偏差信号中不同扭振模态的分离,通过相位补偿和比例放大,生成STATCOM的电流指令。在底层STATCOM控制策略中,考虑电网故障扰动引起的SSO问题,提出了基于分相控制的角型STATCOM控制策略。由于机组SSO发生概率较小,该类STATCOM大多数时间内均处于低载工况,为降低设备长期运行损耗,引入最近电平逼近调制策略,以实现无死区零无功运行,同时该调制策略也利于各链节电容电压平衡。通过RTDS仿真试验证实所提控制策略可有效解决信号激励或故障激励引发的SSO和轴系扭振问题,可推广至工程应用。Aiming at the subsynchronous oscillation （SSO） and torsional vibration problem confronted by larger turbine generators connected to series-compensated power systems,A delta-connected H-bridge cascaded static vat com- pensator（STATCOM） installed on power grid side of the generator sets and a dedicated control strategy to suppressing the SSO is adopted.On the upper control system,a kind of narrow-band subsynchronous damping controller is designed, generator speed deviation is sampled,with through the band-pass filter banks ,various torsional frequencies of the signal are separated, the STATCOM current reference is finally generated by the phase compensation and proportional amplifier components.A dedicated STATCOM control strategy based on individual phase control is proposed to suppress SSO produced by grid fault.A novel nearest level approximation modulation strategy for the full bridge topology is proposed considering this STATCOM working under low load condition in the majority cases.Based on this modulation strategy,the STATCOM equipment loss can be reduced and operate at zero reactive power with the balance of all capacitor voltage.Through RTDS simulation test, the dedicated control strategy is verified to be correct and effective, and can be extended to engineering application.

关 键 词：静止同步补偿器 次同步振荡 分相电流控制 

分 类 号：TN711[电子电信—电路与系统]