Design and analysis of multi-source multi-area deregulated power system for automatic generation control using quasi-oppositional harmony search algorithm

The present article focuses on the study of automatic generation control (AGC) of a realistic power system having a distinct combination of multi-area multi-source generating units in each control area under deregulated framework. An attempt is made in this paper to integrate reheat thermal, hydro and gas generating unit in a single control area and, then, extended this combination to five control areas. In this work, six reheat thermal, six hydro and three gas generating units are taken into account for the modeling of five-area power system. Some important physical constraints like time delay, governor dead band and generation rate constraint are imposed in the power system dynamics to get an accurate perception of the deregulated AGC subject. The highlighting features of the present work are to model, simulate, optimize and co-relate their inter-related dynamic performances for the purpose of AGC study. For such a complex AGC model, the vital role of the proposed quasi-oppositional harmony search (QOHS) algorithm, as an optimizing tool, is signified while solving the AGC problem in deregulated regime. The simplicity of the structure and acceptability of the responses of the well-known proportional–integral–derivative controller, inherently, enforces to employ in this work. The three classes of extensive deregulated cases (in the presence of load following and physical constraints) are demonstrated by examining the closed loop performance of the studied model. The simulation results show that the designed power system model may be a feasible one and the proposed QOHS algorithm may be a promising optimization technique under these circumstances.     

含风电的交直流互联电网AGC两级分层模型预测控制

随着大规模风电接入交直流互联电网,传统的自动发电控制(AGC)方法难以有效地抑制风功率波动带来的频率稳定问题。为此,提出基于两级分层模型预测的AGC策略。该两级分层控制方法在下层对多个区域电网采用分散式模型预测控制;在上层对下层分散的控制器采用动态协调控制方式。以含多电源的两区域交直流互联电网AGC模型为例,仿真结果表明:与集中式模型预测控制和分散式模型预测控制方法相比,文中所提控制策略不仅对频率和联络线功率等具有良好的控制效果,还兼具高可靠性。     

Automatic generation control of TCPS based hydrothermal system under open market scenario: A fuzzy logic approach

This paper presents the analysis of automatic generation control of a two-area interconnected thyristor controlled phase shifter based hydrothermal system in the continuous mode using fuzzy logic controller under open market scenario. Open transmission access and the evolving of more socialized companies for generation, transmission and distribution affects the formulation of AGC problem. So the traditional AGC two-area system is modified to take into account the effect of bilateral contracts on the dynamics. It is possible to stabilize the system frequency and tie-power oscillations by controlling the phase angle of TCPS which is expected to provide a new ancillary service for the future power systems. A control strategy using TCPS is proposed to provide active control of system frequency. Further dynamic responses for small perturbation considering fuzzy logic controller and PI controller (dual mode controller) have been observed and the superior performance of fuzzy logic controller has been reported analytically and also through simulation.     

Effective oscillation damping of an interconnected multi-source power system with automatic generation control and TCSC

Stabilizing area frequency and tie-line power oscillations in interconnected power systems are main concerns that have received significant attention in automatic generation control (AGC) studies. This paper deals with modeling and simulation of thyristor controlled series capacitor (TCSC) based damping controller in coordination with AGC to damp the oscillations and thereby, improve the dynamic stability. The contribution of TCSC in tie-line power exchange is formulated analytically for small perturbation and a systematic method based on the Taylor series expansion is proposed for modeling of TCSC based damping controller. The integral gains of AGC and TCSC parameters are optimized simultaneously using an improved particle swarm optimization (IPSO) algorithm through minimizing integral of time multiplied squared error (ITSE) performance index. The performance of the proposed TCSC–AGC coordinated controller is compared with case of AGC alone. A two-area interconnected multi-source power system, including TCSC located in series with the tie-line, is studied considering nonlinearity effects of generation rate constraint (GRC) and governor dead band (GDB). Simulation results show that proposed controller shows greater performance in damping of the oscillations and enhancing the frequency stability. Furthermore, sensitivity analyses are carried out against system loading condition, parametric uncertainties, and different perturbation patterns to show the robustness of TCSC–AGC.     

基于PSO-GSA算法的含DFIG互联系统AGC优化控制研究

传统双馈感应风力发电机(DFIG)的解耦控制使其无法响应电网的频率变化。随着风电渗透率的不断提高,电网调频压力不断增大,有必要对含DFIG互联系统AGC优化控制进行研究。首先建立了将风电作为"负的负荷"的两区域AGC模型,通过引入改进的虚拟惯性控制使DFIG具有更好的频率响应的能力。同时以快速消除系统区域控制偏差和风机转速偏差为目的,采用PSO-GSA算法对控制区PID控制器和DFIG转速控制单元PI控制器参数进行优化。仿真结果表明,单个区域受负荷扰动时,风电参与调频时能提供更多的有功功率支撑以减小同步机调频出力,能有效缓解同步机调频压力。PSO-GSA算法较PSO和GSA迭代速度快且适应度值更好,基于PSO-GSA参数优化后的控制器对系统区域频率偏差、联络线功率变化和区域控制偏差信号的超调量和调节时间都有明显改善,增强了系统的稳定性。     

Ant Colony Optimized Fuzzy Control Solution for Frequency Oscillation Suppression

This paper presents a novel approach in addressing a critical power system issue, i.e., automatic generation control (AGC) in a smart grid scenario. It proposes the design and implementation of an optimized fuzzy logic controller (FLC) for AGC of interconnected power network. There are three different sources of power generation considered in the two-area interconnected model of power system network. First area is equipped with a single reheat thermal unit and a superconducting magnetic energy storage (SMES) unit, while another area has a hydro-unit with SMES. A multi-stage optimization strategy for the optimal solution of FLC for tie-line and frequency oscillation suppression is proposed in this paper using an ant colony optimization technique. The optimization of FLC is carried out in four different stages. The first stage is the optimization of range of input and output variables; the second stage is the optimization of membership function; the third and fourth stages are the optimization for rule base and rule weight optimization, respectively. The performance of the proposed controller is also compared with another control approaches to stabilize P_tie-line and Δf oscillations; these are the Ziegler–Nichols-tuned proportional–integral–derivative (PID) controller and genetic algorithm optimized PID controller. A comprehensive analysis of the traditional techniques and proposed techniques is presented on the basis of major dynamic performance parameters, i.e., settling time and peak overshoot.     

Quasi oppositional harmony search algorithm based controller tuning for load frequency control of multi-source multi-area power system

This paper deals with the load frequency control (LFC) study of single-area and interconnected two-area power system having diversified power sources. The two areas considered in the present study are identical. Each area is having thermal, hydro and gas based power plants. Split-shaft model of gas turbine is used in the present work as one of the diversified generating unit for the purpose of LFC study. Optimal gains of the classical controllers (like integral controller, proportional–integral controller and proportional–integral–derivative (PID) controller, one installed at a time in the studied models) are obtained by using a novel music-inspired metaheuristic harmony search algorithm (HSA) which incorporates quasi opposition based learning technique for memory initialization and also for generation jumping. Single-area power system with diverse power sources is considered and its optimal transient performances are obtained and compared for step load perturbation. The same approach is further extended to two-area interconnected power system consisting of diverse power sources with nominal values of area input parameters. The performance of PID controller is found to be the best one for the studied power system models. It is also revealed that the performance of the interconnected two-area power system with AC–DC tie line is better in comparison to AC tie line.     

基于串级PI-(1+PD)算法的含飞轮储能互联电网AGC控制器设计

针对传统控制器存在的响应速度较慢、超调较大及鲁棒性较差等问题,提出一种基于串级PI-(1+PD)算法的含飞轮储能互联电网AGC控制器设计方法。首先,建立含飞轮储能的两区域互联电网AGC系统模型,模拟飞轮储能联合火电机组参与AGC的过程。然后,设计一种基于串级PI-(1+PD)算法的AGC控制器。外环采用PI控制,内环采用带滤波系数的(1+PD)控制。在保证系统稳态性能的前提下,提高动态响应速度和抗扰能力,并通过粒子群算法的迭代寻优获得最优的控制器参数。最后,基于Matlab/Simulink进行算例仿真分析。结果表明：与传统PID控制和PI-PD控制相比,所提方法不仅具有更快的响应速度与更小的超调量,而且增强了系统抵御内部参数摄动的鲁棒性。     

Automatic Generation Control in an Interconnected Power System Incorporating Diverse Source Power Plants Using Bacteria Foraging Optimization Technique

This article presents automatic generation control (AGC) of a two-area interconnected power system with diverse energy sources using the bacteria foraging optimization technique. The control areas of interconnected power systems consist of hydro, thermal, and gas power plants. In this study, the proportional-integral-derivative (PID) structures of AGC regulators are designed for various case studies identified herein. An artificial intelligent optimization algorithm using the modeling behavior of E. Coli bacteria present in human intestines, is applied to tune the gains of PID structured AGC regulators. The closed-loop system dynamic response plots are obtained with designed AGC regulators for various power system models. The effectiveness of the proposed AGC regulators is demonstrated in the wake of a 1% step load disturbance in one of the control areas. It has been shown that the system dynamic responses subject to a step load disturbance are superior over other power plant combinations in a control area with only thermal and gas power plants participating in the AGC schemes, and it is sluggish/poor when only hydro power plants participated in the AGC scheme as one of the diverse sources in the power system.     

考虑风机虚拟惯性的预测优化PIDD2自动发电控制方法

风电的大规模渗透,使分布式发电系统的自动发电控制(automatic generation control, AGC)必须应对自然环境不确定性所带来的影响,构建了风电机组参与频率调节的区域互联电网AGC模型;然后,对风机虚拟惯性的控制特性进行了分析,将其应用于短时负荷波动的快速响应;在此基础上,提出一种对带有二阶微分的比例积分微分控制器(proportional integral differential plus second order derivative, PIDD2)进行预测优化的控制策略。通过建立含PIDD2控制器的AGC模型,采用预测算法计算该系统的最优预测序列,并据此调整PIDD2控制器的参考信号,从而获取最优的AGC效果。仿真结果表明:在大规模风电渗透的AGC系统中,所提方法能有效解决传统固定参数PID控制器对系统动态变化所表现的不适应性问题。     

Power-Frequency Balance in Multi-generation System Using Optimized Fuzzy Logic Controller

This paper emphasizes the development of control strategy for inter-area oscillation suppression for a unified two-area hydro–thermal deregulated power system. A proportional derivative-type fuzzy logic controller with integral (PDFLC+I) controller was proposed for automatic generation control. Further comparisons among conventional integral controller, proportional integral derivative controller, and PDFLC+I are carried out, where the PDFLC+I controller is optimized by four different optimization techniques namely, algorithm, ant colony optimization, classical particle swarm optimization, and adaptive particle swarm optimization. In PDFLC+I controller optimization, scaling parameters of controllers are optimized. A comparative study shows that the proposed PDFLC+I controller has a better dynamic response following a step load change for the combination of PoolCo and bilateral contract-type transaction in deregulated environment. Proposed controller performance has also been examined for ±30% variation in system parameters. Non-linearity in the form of governor dead band is taken into account during simulation.     

基于AGC的高压互联网络频率协调控制

针对高压互联网络频率协调困难,而自动发电控制存在控制跟踪性能差、参数最优值获取难、优化效果不明显等问题,提出了一种基于模拟退火粒子群寻优算法的闭环反馈自动发电控制。改进后的寻优算法结合了模拟退火和粒子群算法的优点,通过该算法对控制器关键参数进行寻优以使区域控制偏差值最小。由MATLAB/Simulink仿真分析验证了四机两区域模型联络线发生故障时,改进参数的闭环反馈AGC控制器能较快地使系统恢复稳定,且能较好地达到频率协调的控制作用。     

AGC of a multi-area multi-source hydrothermal power system interconnected via AC/DC parallel links under deregulated environment

This paper proposes the automatic generation control (AGC) of an interconnected multi-area multi-source hydrothermal power system under deregulated environment. The two equal control areas with hydro and thermal generating power sources are interconnected via AC/DC parallel links. The optimal proportional integral (PI) regulators are designed for the proposed power system to simulate all power market transactions which are possible in a restructured power system. The concept of DISCO participation matrix (DPM) is harnessed to simulate the transactions. Eigenvalue study is conducted to assess the effect of AC/DC parallel links on system performance. The study is also conducted, considering appropriate generation rate constraints (GRCs) for thermal and hydro generating sources. Further, the dynamic responses of the proposed multi-source hydrothermal power system are compared with single-source thermal–thermal power system and it has been ascertained that the responses of proposed power system are sluggish with large overshoots and settling times. Finally, the study is extended to frame and implement optimal PI regulators for the first time for the AGC of a conventional two-area non-reheat thermal power system with governor dead-band nonlinearity. The superiority of the optimal PI regulators has been established by comparing the results with recently published best claimed craziness based particle swarm optimization (CRAZYPSO) and hybrid bacterial foraging optimization algorithm-particle swarm optimization (hBFOA-PSO) algorithms based PI controller tuned for the same interconnected power system.     

Automatic generation control: Decentralized area-wise optimal solution

A decentralized scheme is proposed for the design of automatic generation control (AGC) for interconnected power systems. This scheme uses the natural structural properties of interconnected power systems and gives a new method for decentralized AGC regulator design, using the existing theory of proportional-plus-integral linear regulators applied to each individual power area. It is shown that a decentralized design, based upon the expansion-contraction theory of large-scale systems with overlapping and modified linear regulators with incomplete subsystem feedback, is suitable to handle the design of AGC regulators for present-day interconnected power systems. The resulting AGC retains the autonomous area control concept and load distribution property of conventional AGC regulators, while at the same time allows for improved transients and stability margins for interconnected areas. The application of this decentralized AGC scheme is illustrated on a 17th-order model of a two-area interconnected power system.     

Hybrid Taguchi Genetic Algorithm-Based AGC Controller for Multisource Interconnected Power System

This article presents hybrid Taguchi-genetic algorithm (HTGA) tuned automatic generation controller for two areas interconnected multisource power system model. The control areas consist of thermal, hydro, and doubly fed induction generator-based wind power plants. The optimal tuning of AGC controller using genetic algorithm is less robust due to larger standard deviation of the fitness values. Therefore, Taguchi method which is based on modified statistical approach and has systematic reasoning ability is used to enhance the performance of genetic algorithm. The simulation study is carried out with the optimum gains of AGC controller obtained from HTGA, conventional GA and conventional techniques. The dynamic stability of the power system model is examined to analyze the performance of the HTGA technique. From investigations it is quite clear that the optimum gains of AGC system obtained from HTGA technique has better response in the dynamic stability of the interconnected multisource power system as compared to genetic algorithm and conventional technique.     

双馈风电机组附加阻尼控制器与同步发电机PSS协调设计

针对大规模双馈风电机组接入电力系统后的区间低频振荡问题,提出了一种协调双馈风电机组附加阻尼控制器和同步发电机电力系统稳定器(PSS)的设计策略。首先,考虑风电机组的机械部分、电气部分和控制结构,建立了双馈风电机组的机电暂态模型和附加阻尼控制器模型。在闭环电力系统线性化模型的基础上,提出利用动态指标值的优化模型来协调整定双馈风电机组附加阻尼控制器和同步发电机PSS的控制参数,并使用粒子群算法求解优化模型的全局最优解。最后,通过2个标准仿真系统算例,对比传统的阻尼控制器设计策略,验证了所设计策略的有效性和实用性。     

基于虚拟狼群策略的分层分布式自动发电控制

为解决传统集中式自动发电控制(AGC)无法解决的大规模新能源接入电网所带来的强随机扰动问题,从AGC角度提出一种面向分布式能源、基于虚拟狼群策略的分层分布式控制方法,以实现区域的最优协同控制。该方法简称虚拟狼群策略,它结合新赢输评判标准、爬山算法和资格迹,通过智能体精确计算赢输评判标准并快速收敛到纳什均衡;在总功率指令分配部分采用协同一致性算法。通过对IEEE标准两区域电力系统改进模型以及湖北电网模型进行仿真,表明所提方法能实现区域协同控制、改善闭环系统性能、减少碳排放,同时具有更快的收敛速度。     

多控制区协调自动发电控制的研究与实现

为了解决电源送出问题,提出一种多控制区协调自动发电控制(AGC)模型。结合该模型,对AGC的行为与电网潮流之间的作用关系进行分析,给出了相应的控制策略及控制算法。主控制区的控制目标为频率和联络线偏差控制,子控制区的控制目标为其稳定断面潮流贴近控制要求。子控制区也可参与主控制区的控制,实现与主控制区的协调控制。在云南省调AGC的实际工程应用表明,该方法可以有效地将子控制区稳定断面有功功率控制在允许范围内,保证电力系统的安全稳定运行。     

ANFIS Based Control Design for AGC of a Hydro-hydro Power System with UPFC and Hydrogen Electrolyzer Units

This paper presents the design of artificial neuro fuzzy inference system (ANFIS) based automatic generation control (AGC) scheme for a two-area hydro-hydro dominating power system. The proposed control scheme is flexible with simple structure and may prove to be a promising tool for considered system in the presence of system non-linearity and for wide range of parametric variations. The ANFIS based control are implemented and the system dynamic responses are obtained considering 1% load disturbance in area-1 and compared with fuzzy and conventional proportional integral (PI) based AGC to show the simplicity and effectiveness of the proposed control. The further improvements in the system dynamic responses with the proposed control are observed by considering the unified power flow control (UPFC) in series with the tie-line and hydrogen aqua electrolyzer units installed at one of the terminal of the control areas. The dynamic performance of the designed control is also evaluated considering the governor dead-band and generation rate constraint (GRC) non-linearity and for wide range of system parametric variations.     

含抽水蓄能电站的互联电网负荷频率自抗扰优化控制研究

针对发电能源结构的多元化发展给互联电网负荷频率的稳定性控制带来较大的挑战,建立含抽水蓄能电站的两区域互联电网多元混合发电的负荷频率控制模型,提出一种基于粒子群优化算法的负荷频率线性自抗扰控制器参数整定优化策略,通过粒子群算法的迭代寻优计算获得最优的线性自抗扰控制器参数.考虑互联电网各区域发生不同的负荷扰动,在抽水蓄能电...