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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 current research, static var compensator (SVC) suppresses subsynchronous oscillation, and most of them are connected to the terminal or boost to high voltage side, and only damping control is considered, and other access positions and voltage regulation are discussed Not much, the controller design is not easy enough. In this paper, based on the dq axis mathematical model of the system, the calculation of the complex torque coefficient is simplified, and the more accurate electromagnetic torque expression of the SVC series compensation system is obtained. Using this formula to analyze the additional damping mechanism of SVC and the relationship with the access position, it is pointed out that the midpoint of the access line can make the SVC provide more positive damping near the resonance frequency. At the same time, the influence of SVC voltage control on sub-synchronous oscillation is analyzed. It is pointed out that the voltage-controlled transfer function is likely to increase the additional damping phase difference at each torsional vibration frequency. A PID control design based on phase compensation method is proposed in this paper. The parameter setting is simple and fast, which can not only maintain the system voltage level and improve the line transmission capacity, but also restrain the system subsynchronous oscillation effectively. Eigenvalue calculation and time domain simulation prove the correctness of the analysis results.