Koteswara Raju D, Umre Bhimrao S, Junghare Anjali S, Thakre Mohan P, Motamarri Rambabu, Somu Chaitanya
Department of Electrical Engineering, VNIT, Nagpur, Maharashtra India.
Electrical and Electronics Engineering Department, Aditya Engineering College, Kakinada, Andhrapradesh India.
Springerplus. 2016 Sep 19;5(1):1599. doi: 10.1186/s40064-016-2727-y. eCollection 2016.
This research article proposes a powerful fractional-order PI controller to mitigate the subsynchronous oscillations in turbine-generator shaft due to subsynchronous resonance (SSR) with flexible AC transmission system devices such as static synchronous compensator (STATCOM) and unified power flow controller (UPFC). The diminution of SSR is achieved by the raising of network damping at those frequencies which are proximate to the torsional mode frequency of the turbine-generator shaft. The increase of network damping is obtained with the injection of subsynchronous frequency component of current and both current and voltage into the line. The subsynchronous component of current and voltage are derived from the measured signal of the system and further the same amount of shunt current is injected with STATCOM and simultaneous injection of current and voltage with UPFC into the transmission line to make the subsynchronous current to zero which is the prime source of turbine shaft oscillations. The insertion and proper tuning of Fractional-order PI controller in the control scheme, the subsynchronous oscillations are reduced to 92 % in case of STATCOM and 98 % in case of UPFC as compared to without controller and 14 % as compared with the results of conventional PI controller. The IEEE first benchmark model has adopted for analyze the effectiveness and speed of the proposed control scheme using MATLAB-Simulink and the corresponding results illustrates the precision and robustness of the proposed controller.
本文提出了一种强大的分数阶PI控制器，以减轻由于与柔性交流输电系统装置（如静止同步补偿器（STATCOM）和统一潮流控制器（UPFC））发生次同步谐振（SSR）而导致的汽轮发电机轴系中的次同步振荡。通过提高接近汽轮发电机轴系扭转模式频率的那些频率下的网络阻尼来实现SSR的减小。通过向线路中注入电流的次同步频率分量以及电流和电压来获得网络阻尼的增加。电流和电压的次同步分量从系统的测量信号中导出，并且进一步通过STATCOM注入相同量的并联电流，并通过UPFC同时向传输线注入电流和电压，以使作为汽轮机轴振荡主要来源的次同步电流变为零。通过在控制方案中插入分数阶PI控制器并进行适当调整，与无控制器的情况相比，STATCOM情况下次同步振荡降低了92%，UPFC情况下降低了98%，与传统PI控制器的结果相比降低了14%。采用IEEE第一个基准模型，利用MATLAB-Simulink分析所提出控制方案的有效性和速度，相应结果说明了所提出控制器的精度和鲁棒性。
