基于TCSC的混合串补抑制次同步振荡的研究

Study of hybrid compensation scheme based on TCSC damping sub-synchronous oscillation

研究了一种基于可控串补(TCSC)的混合串补(HTCSC)抑制次同步振荡的新方法。与三相TCSC相比,该方法只在单相上接TCSC,减少了2/3的晶闸管数量,降低了成本及控制难度。采用同步电压反转(SVR)控制方法,并设计出主动阻尼控制器。时域仿真结果表明,采用基于SVR方法的主动阻尼控制器后,HTCSC能有效抑制由线路串补度不合理引起的次同步振荡问题,且短路故障后的电压不平衡度稳态值能满足国家标准的限值要求。

A novel hybrid thyristor controlled series compensation ( HTCSC) scheme for damping the sub-synchro-nous oscillation is studied. In HTCSC structure, TCSC device is connected to single phase and the other two phases use only the fixed compensation capacitor. Under basic power frequency, the three phase impedance is equal;while under sub-synchronous frequency, impedance of three phase is unequal, thus the three-phase current is im-balance, which can weaken the coupling between generator and electrical system and inhibit SSO to a certain ex-tent. Compared with three-phase TCSC, the new structure reduces number of thyristor by 2/3, and lowers the de-vice cost and control difficulty. Synchronous voltage reversal ( SVR) method is used as the control strategy and a supplementary active damping controller is designed. The simulation result shows that with the active damping con-troller based on SVR, HTCSC can effectively suppress the sub-synchronous oscillation caused by unreasonable line compensation degree. Moreover, the steady-state value of line voltage unbalanced rate under HTCSC scheme after a short-circuit fault can meet the requirements of national standard.