Design of integral controller for Load Frequency Control of Static Synchronous Series Compensator and Capacitive Energy Source based multi area system consisting of diverse sources of generation employing Imperialistic Competition Algorithm

This paper presents the design of integral controller for Load Frequency Control (LFC) under deregulated environment having diverse sources of power generation employing Imperialistic Competition Algorithm (ICA). Static Synchronous Series Compensator (SSSC) along with Capacitive Energy Storage (CES) has also been proposed to further increase the dynamic performance of the system in terms of peak time, overshoot and settling time. The concept of soft computing techniques greatly helps in overcoming the disadvantages posed by the conventional controllers. Open transmission access and the evolving of more socialized companies for generation, transmission and distribution affects the formulation of LFC problem. So the traditional LFC system is modified to take into account the effect of bilateral contracts on the dynamics. Simulation results show that the Imperialistic Competition Algorithm based system employing Static Synchronous Series Compensator and Capacitive Energy Source has better dynamic performance over the system without these parameters.     

Adaptive Polar Fuzzy logic based Load Frequency Controller

Performance of a Fuzzy logic controller is dependent on sufficient and accurate knowledge base. As the number of rules in a knowledge base increases, its complexity increases which in turn affects the computation time and memory requirements. To overcome these problems, a Polar Fuzzy logic controller is proposed. The aim of the Polar Fuzzy Controller (PFC) is to restore the frequency and tie-line power in a smooth way to its nominal value in the shortest possible time if any load disturbance is applied to any area of power system. In this paper, the PFC is made adaptive using a Genetic algorithm-fuzzy system (GAF) approach. Performance of the simple PFC and adaptive PFC using GAF is compared with fuzzy and conventional PI controllers on a three area system.     

考虑GRC的多区域电力系统负荷频率分散控制

本文讨论了将突迭分解分散控制理论应用于区域性电力系统的负荷频率控制(LFC)的可行性,并提出了一种新的控制系统设计方法。该方法不仅保持了交造分解分散控制的一切优点,考虑了发电速度的限制,而且有效地改善了控制系统的动态品质。对两区域电力系统进行的LFC系统设计及仿真,结果表明本设计方法是可行的,且具有一定的优越性。     

Cuckoo Search algorithm based load frequency controller design for nonlinear interconnected power system

A new optimization technique called Cuckoo Search (CS) algorithm for optimum tuning of PI controllers for Load Frequency Control (LFC) is suggested in this paper. A time domain based-objective function is established to robustly tune the parameters of PI-based LFC which is solved by the CS algorithm to attain the most optimistic results. A three-area interconnected system is investigated as a test system under various loading conditions where system nonlinearities are taken into account to confirm the effectiveness of the suggested algorithm. Simulation results are introduced to show the enhanced performance of the developed CS based controllers in comparison with Genetic Algorithm (GA), Particle Swarm Optimization (PSO) and conventional integral controller. These results denote that the proposed controllers offer better performance over others in terms of settling times and various indices.     

遗传算法PID参数优化的改进

介绍了遗传算法的基本原理 ,并针对简单遗传算法在PID控制中存在的问题进行了分析 ,提出在不同情况下采用不同的变异概率的方法 ,并分别进行了实验仿真。仿真结果表明 ,用改进的遗传算法优化PID参数 ,可以提高优化性能 ,对控制系统具有良好的控制精度、动态性能和鲁棒性     

海外工程中基于BOT项目的孤网负荷与频率控制技术研究

负荷和频率控制系统LFC作为火电项目生产中的要控制主要指标,是影响其安全生产的重要因素。通过分析印尼电网负荷和频率控制(LFC)原理着手,结合购电协议(PPA)分析其意义,揭示负荷和频率控制关键点,在印尼电网孤网和容量小的特殊情况下,同时电网负荷和频率控制系统对IPP投资电厂的安全稳定运行有重要意义,在实际调试和运行过程中必须非常关注,以便保证电网稳定、电厂运行安全,获得最大收益。     

基于尼科尔斯PID设计方法的负荷频率控制

为解决互联水电系统负荷频率控制(load frequencycontrol,LFC)问题,及保持互联电网系统频率、联络线功率及区域控制误差(area control error,ACE)的稳定,根据闭环系统谐振峰值与系统响应最大峰值之间的关系,构建一个与系统参数及控制器参数都相关的优化问题,通过该问题的求解获得控制器参数与系统参数之间的数学关系,针对水轮发电系统非最小相位特性,通过串加比例–微分(proportional-derivative,PD)控制方式降低系统阶次,设计尼科尔斯(Nichols)曲线的比例–积分–微分(proportional-integral-derivative,PID)控制器。基于模型参数扰动和负荷干扰的仿真结果表明:尼科尔斯PID控制器能快速调整系统频率偏差、联络线功率偏差及ACE为0,具有良好的鲁棒性能和抗负荷干扰性能,系统过渡过程性能明显优于传统PID调节器结果。     

A new PID load frequency controller design method in frequency domain through direct synthesis approach

In this paper a new PID controller design method based on the direct synthesis (DS) approach of controller design in frequency domain is presented. The parameters of the PID controller are obtained through frequency response matching with the DS controller. The method yields linear algebraic equations, solution of which gives the controller parameters. The design method has been developed for single-area as well as multi-area power systems. Non-linearity like the generation rate constraint (GRC) has been considered. Several examples are taken from the literature to demonstrate the effectiveness of the proposed method in comparison with some prevalent design methods.     

论变频空调器的频率控制逻辑

通过对目前常用的几种变频空调器制冷频率控制逻辑的介绍,分析、探讨频率控制逻辑对变频空调器舒适性的影响。     

基于PID负荷频率控制的电力系统时滞相关鲁棒稳定性分析

基于Lyapunov-Krasovskii泛函方法讨论了单区域电力系统负荷频率控制问题。建立了考虑通信时滞环节的系统模型,并将基于PID控制器的系统转换为具有反馈控制的闭环系统,构造合适的Lyapunov-Krasovskii泛函,并应用逆凸不等式方法处理泛函导数中的积分项,推导出系统矩阵中含有PID参数的鲁棒稳定性判据。并结合数值实例分析了系统在不同时滞类型的情况下,PI控制增益与系统时滞稳定裕度之间的关系,仿真结果表明了文中方法的有效性和相比已有方法的优越性。     

PID controller design for hydraulic turbine based on sensitivity margin specifications

The paper presents a proportional-integral-derivative (PID) controller design procedure for a hydraulic turbine generator governor meeting sensitivity margin specifications. The closed-loop performance is guaranteed over wide range of operating conditions of the interconnected system. The main advantage of the proposed method consists in the simple design using only one tuning parameter. The control performance of the presented method is compared on simulations with the procedure guaranteing gain and phase margins using non-convex optimization.     

Bacteria foraging optimization algorithm based load frequency controller for interconnected power system

Social foraging behavior of Escherichia coli bacteria has recently been explored to develop a novel algorithm for distributed optimization and control. The Bacterial Foraging Optimization Algorithm (BFOA), as it is called now, is currently gaining popularity in the community of researchers, for its effectiveness in solving certain difficult real world optimization problems. This paper proposes BFOA based Load Frequency Control (LFC) for the suppression of oscillations in power system. A two area non-reheat thermal system is considered to be equipped with proportional plus integral (PI) controllers. BFOA is employed to search for optimal controller parameters by minimizing the time domain objective function. The performance of the proposed controller has been evaluated with the performance of the conventional PI controller and PI controller tuned by genetic algorithm (GA) in order to demonstrate the superior efficiency of the proposed BFOA in tuning PI controller. Simulation results emphasis on the better performance of the optimized PI controller based on BFOA in compare to optimized PI controller based on GA and conventional one over wide range of operating conditions, and system parameters variations.     

高频UPS的两种新型节能控制方式

本文介绍了两种新型高频UPS的节能控制法的基本工作原理与控制方法。     

基于区间分析的参数不确定系统PID鲁棒控制器设计

针对区间对象PID鲁棒控制器设计问题,提出了一种基于广义Kharitonov定理和区间分析集逆算法的设计方法。该方法根据广义Kharitonov定理将区间对象的鲁棒稳定控制器综合问题转化为多个顶点对象同时稳定的控制器综合问题,根据劳斯判据得到与控制器参数相关的不等式组,采用基于区间分析的集逆算法求解该不等式组得到PID鲁棒控制器参数。数值算例表明所提出的设计方法可以以任意设定精确度逼近使得整个区间对象族稳定的PID控制器参数域,与传统图解法相比求得的结果是可靠的,同时该方法能够根据集逆算法解集情况准确判断假定的控制器是否可行。     

Frequency domain design of fractional order PID controller for AVR system using chaotic multi-objective optimization

A fractional order (FO) PID or FOPID controller is designed for an Automatic Voltage Regulator (AVR) system with the consideration of contradictory performance objectives. An improved evolutionary Non-dominated Sorting Genetic Algorithm (NSGA-II), augmented with a chaotic Henon map is used for the multi-objective optimization based design procedure. The Henon map as the random number generator outperforms the original NSGA-II algorithm and its Logistic map assisted version for obtaining a better design trade-off with an FOPID controller. The Pareto fronts showing the trade-offs between the different design objectives have also been shown for both the FOPID controller and the conventional PID controller to enunciate the relative merits and demerits of each. The design is done in frequency domain and hence stability and robustness of the design is automatically guaranteed unlike the other time domain optimization based controller design methods.     

sf型矢量控制系统参数变化对系统控制性能的影响分析和补偿方法

转差频率(sf)型矢量控制系统是一种较为实用的矢量控制系统。但由于该系统是磁通开环控制的,因此,系统动、静态性能对参数变化较敏感。本文着力定量分析并验证了参数变化对系统性能的影响,提出了系统中关键性参数 K_s (转差增益)的整定及补偿方法。本文是以电流源型逆变器进行系统试验的。     

Load frequency control of power system under deregulated environment using optimal firefly algorithm

In this paper, a novel Firefly Algorithm (FA) optimized hybrid fuzzy PID controller with derivative Filter (PIDF) is proposed for Load Frequency Control (LFC) of multi area multi source system under deregulated environment by considering the physical constraints such as Generation Rate Constraint (GRC) and Governor Dead Band (GDB) nonlinearity. As the effectiveness of FA depends on algorithm control parameters such as randomization, attractiveness, absorption coefficient and number of fireflies are systematically investigated, the control parameters of FA are tuned by carrying out multiple runs of algorithm for each control parameter variation then the best FA control parameters are suggested. Additionally, the superiority of the FA is demonstrated by comparing the results with tuned Genetic Algorithm (GA). To investigate the effectiveness of the proposed approach, time domain simulations are carried out considering different contracted scenarios and the comparative results are presented. Further, sensitivity analysis is performed by varying the system parameters and operating load conditions. It is observed from the simulation results that the designed controllers are robust and the optimum gains of proposed controller need not be reset even if the system is subjected to wide variation in loading condition and system parameters. Finally, the effectiveness of the proposed control scheme is evaluated under random step load disturbance.     

Optimal SSSC design for damping power systems oscillations via Gravitational Search Algorithm

In recent years, various heuristic optimization methods have been developed. Many of these methods are inspired by swarm behaviors in nature. In this paper, a new optimization algorithm namely Gravitational Search Algorithm (GSA) based on the law of gravity and mass interactions is illustrated for designing Static Synchronous Series Compensator (SSSC) for single and multimachine power systems. In the proposed algorithm, the searcher agents are a collection of masses which interact with each other based on the Newtonian gravity and the laws of motion. The proposed method has been compared with some well-known heuristic search methods. The obtained results confirm the high performance of the proposed method in tuning SSSC compared with Bacteria Foraging (BF) and Genetic Algorithm (GA). Moreover, the results are presented to demonstrate the effectiveness of the proposed controller to improve the power systems stability over a wide range of loading conditions.     

Bat inspired algorithm based optimal design of model predictive load frequency control

Bat inspired algorithm (BIA) has recently been explored to develop a novel algorithm for distributed optimization and control. In this paper, BIA-based design of model predictive controllers (MPCs) is proposed for load frequency control (LFC) to enhance the damping of oscillations in power systems. The proposed model predictive load frequency controllers are termed as MPLFCs. Two-area hydro-thermal system, equipped with MPLFCs, is considered to accomplish this study. The suggested power system model considers generation rate constraint (GRC) and governor dead band (GDB). Time delays imposed to the power system by governor-turbine, thermodynamic process, and communication channels are accounted for as well. BIA is utilized to search for optimal controller parameters by minimizing a candidate time-domain based objective function. The performance of the proposed controller has been compared to those of the conventional PI controller based on integral square error (ISE) technique and the PI controller optimized by genetic algorithms (GA), in order to demonstrate the superior efficiency of the BIA-based MPLFCs. Simulation results emphasis on the better performance of the proposed MPLFCs compared to conventional and GA-based PI controllers over a wide range of operating conditions and system parameters uncertainties.     

基于PID的互联电力系统LFC的优化研究

针对两区域互联电力系统在受到外界负荷扰动后系统负荷频率的变化规律,基于TBC—TBC联络线频率偏差的控制模式,先后利用经典的PID控制技术和前馈补偿控制技术,对两区域互联电力系统负荷频率的控制算法进行优化研究,使两区域的电力系统在突然遭受负荷扰动时能迅速可靠地减少频率偏差和联络线交换功率偏差,恢复系统的安全稳定运行。在MATLAB7.8.0/Simulink软件的仿真下,其结果表明,经过前馈补偿后的PID控制比经典PID控制具有更佳的控制效果和鲁棒性。