改变直流电流控制器特性抑制次同步振荡的机理及实现

Mechanism and Implementation for SSO Suppression Through Altering Characteristics of CCA Controller in HVDC Control

当高压直流（HVDC）整流站主要输送配套火电基地电力时,利用高压直流附加控制抑制次同步振荡（SSO）是一种经济有效的措施。基于单机和高压直流的简化模型,分析了整流站直流电流控制器（CCA）电流偏差增益对发电机次同步电气阻尼的影响,提出动态改变控制器增益抑制次同步振荡的控制策略及其工程实现方法。该方法通过优化直流电流控制器动态响应特性,改善了直流控制器在次同步频率范围内的阻尼。算例证明该算法可以快速抑制发电机次同步振荡,同时对直流系统原有的动态性能和暂态响应没有影响。与目前工程中应用的附加阻尼控制器相比,该方法实现简便,抑制效果好。

When a rectifier station of high voltage direct current（HVDC） system mainly transmits power of nearby thermal generators, supplementary control function of HVDC control system is widely used to suppress sub-synchronous oscillation（SSO） because of its economic and effectiveness. In this paper, the influence of gain in rectifier current control amplifier（CCA） on sub-frequency electric damping is analyzed and calculated based on a simplified model of single generator plus HVDC. A control strategy of altering the gain of CCA in HVDC control and its project realization algorithm is proposed to eliminate SSO. This method improves the electric damping of HVDC through optimization of CCA characteristic. Simulation shows that the SSO of generator shafts can be mitigated rapidly after applying the method, and the dynamic performance as well as transient response of HVDC system is not impaired simultaneously. Compared to the presently-used SSDC method, this method is easy to be realized and achieves a good damping effect.