Heshmati Mina, Noroozian Reza, Jalilzadeh Saeid, Shayeghi Hossein
Department of Electrical Engineering, University of Zanjan, Zanjan, Iran.
Department of Electrical Engineering, University of Zanjan, Zanjan, Iran.
ISA Trans. 2020 Feb;97:202-215. doi: 10.1016/j.isatra.2019.08.028. Epub 2019 Aug 30.
This paper presents a new robust load frequency control (LFC) technique based on an optimal design of the coefficient diagram method (CDM) in a three area thermal power system equipped with redox flow batteries (RFB). In order to emphasize on a realistic power system and obtain an accurate insight, important nonlinearities due to generation rate constraint (GRC), governor dead band (GDB) and time delay (TD) were considered. The innovation of the proposed controller in this paper is the use of a hybrid intelligent combination of a decentralized CDM technique and optimization throughout its algebraic equations. In addition, a new algorithm namely grasshopper optimization algorithm (GOA) was used to find the key parameters of the proposed controller in solving the LFC problem for the first time. Furthermore, this study applied a powerful modified objective function by considering the integral of time multiplied squared error (ITSE) criteria for both controller input signal (ACE), to minimize the area control error and output signal (Δu) to reduce the size of the actuator, settling time (Ts) to have a faster response and a function to increase the minimum damping ratio (MDR) among all eigen values. To demonstrate the effectiveness of the proposed scheme, the studied simulated power system was tested through different cases including a large step and sinusoidal load perturbations and wide uncertainty in dynamic parameters of a nonlinear power system. Comparative results have revealed the superiority of the optimal CDM technique, especially when it is equipped with RFB. In addition to graphical results, by taking into account the MDR of different control strategies, the preference of the proposed controller has become more validated. This newly developed strategy leads to a flexible and accurate controller with a powerful mathematical back up which can successfully cope with GRC, GDB and TD nonlinearities in perturbed uncertain power systems and provide fast, stable and robust dynamic responses. Thus, the proposed control strategy can be constructive and successfully applied to real world power system application.
本文提出了一种基于系数图法（CDM）优化设计的新型鲁棒负荷频率控制（LFC）技术，该技术应用于配备氧化还原液流电池（RFB）的三区域热力发电系统。为了突出实际电力系统并获得准确的见解，考虑了由于发电速率约束（GRC）、调速器死区（GDB）和时间延迟（TD）引起的重要非线性因素。本文所提出控制器的创新之处在于使用了分散式CDM技术与贯穿其代数方程的优化方法的混合智能组合。此外，首次使用了一种名为蚱蜢优化算法（GOA）的新算法来寻找所提出控制器的关键参数，以解决LFC问题。此外，本研究通过考虑控制器输入信号（ACE）的时间乘平方误差积分（ITSE）准则，应用了一个强大的修正目标函数，以最小化区域控制误差；对于输出信号（Δu），以减小执行器的尺寸；对于调节时间（Ts），以实现更快的响应；以及一个用于增加所有特征值中的最小阻尼比（MDR）的函数。为了证明所提方案的有效性，对所研究的模拟电力系统进行了不同工况的测试，包括大阶跃和正弦负荷扰动以及非线性电力系统动态参数的广泛不确定性。对比结果揭示了最优CDM技术的优越性，特别是当它配备RFB时。除了图形结果外，通过考虑不同控制策略的MDR，所提控制器的优势得到了进一步验证。这种新开发的策略产生了一个灵活且精确的控制器，具有强大的数学支持，能够成功应对扰动不确定电力系统中的GRC、GDB和TD非线性，并提供快速、稳定和鲁棒的动态响应。因此，所提出的控制策略具有建设性，可成功应用于实际电力系统。
