SVC接入位置对次同步振荡的影响机理与SVC控制策略研究

Influence of SVC Location on Subsynchronous Oscillation and SVC Control Strategy Research

当前研究静止无功补偿器(static var compensator,SVC)抑制次同步振荡,大多将其接入机端或升压变高压侧,并仅考虑阻尼控制作用,对其它接入位置和电压调节的探讨不多,控制器的设计也不够简便。文中基于系统的dq轴数学模型,简化复转矩系数的计算,得到较精确的含SVC串补系统的电磁转矩表达式。利用该式分析SVC附加阻尼的机理以及与接入位置的关系,指出接入线路中点能使SVC在谐振频附近提供更多正阻尼。同时分析SVC电压控制对次同步振荡的影响,指出电压控制的传递函数很可能会增大各扭振频下的附加阻尼相位差。对此提出一种基于相位补偿法的PID控制设计,参数整定简单快速,既可以维持系统电压水平和提高线路传输能力,也可有效抑制系统次同步振荡。特征值计算和时域仿真都证明了分析结果的正确性。

： In the researches of damping subsynchronous oscillation （SSO） by static var compensator （SVC）, SVC was more placed at the terminal of generator or high voltage side of step-up transformer. Also the SVC only included a pure damping Control. The studies of other locations and its voltage loop were fewer, and the design of the controller was not simple. Based on the dq mathematic model of the power system, calculation of the complex torque coefficient was simplified, and a more exact formula of electromagnetic torque used in series compensated system including SVC was derived. The influence of SVC location on its supplementary damping was analyzed. It revealed that SVC can provide more damping in resonance frequency when it is placed at middle of line. Impact of voltage control of SVC on SSO was also studied. Its transfer function would increase the phase displacement of supplementary damping between torsional frequencies. Therefore, a design method of PID controller based on phase compensation was proposed. Parameter tuning is simple and fast. The controller not only maintains system voltage level and enlarges the circuitry of transmitted power but also suppress subsynchronous oscillation. All of the conclusions were confirmed by the eigenvalue calculation and time domain simulations.