Optimal Automatic Generation Control with Hydro,Thermal, Gas,and Wind Power Plants in 2-Area Interconnected Power System

Abstract

This paper explores automatic generation control (AGC) of a more realistic 2-area multi-source power system comprising hydro, thermal, gas, and wind energy sources-based power plants in each control area. The wind power plants (WPPs) have been growing continuously worldwide due to their inherent feature of providing eco-friendly sustainable energy. But, operations of WPPs are associated with system stability problems due to lack of inertia. However, WPPs do not participate in the elimination of mismatch between generation and demand by AGC but disturbance can be injected by the WPPs due to the stochastic nature of wind energy. An optimal controller based on full state feedback control theory is designed to conduct the study. The system dynamic performance analysis is carried out for 1% step load disturbance in corresponding control areas. It is observed that the system dynamic graphs of deviation in area frequency and tie-line power are significantly improved with the implementation of optimal AGC controller compared to GA tuned classical controller. It has also been shown that the WPPs aid the increase in load disturbance when the input wind power reduces but it negates the effect of increase in load disturbance for increase in wind energy to the WPPs.     

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.     

计及大规模电动汽车接入的AGC功率动态分配深度交互教学优化算法

为提高区域电网自动发电控制(automatic generation control,AGC)的控制性能指标,利用接入电网的大规模电动汽车参与AGC。在满足车主充电需求的前提下,建立了电动汽车的实时上下调节容量评估模型。在此基础上,构建了电动汽车集群与传统水电、火电机组的AGC功率分层分配框架。为满足上层不同类型机组的快速经济分配,提出了一种深度交互教学(deep interactive teaching-learning,DITL)优化算法进行求解,该算法在标准教学优化算法的基础上,将单个班级扩展到多个班级,并采用小世界交互网络构建不同教师/学生之间的交互网络,从而提升算法的全局搜索及局部搜索能力。在电动汽车集群内部,则根据调节成本系数实现第二层不同局部控制中心的AGC功率分配,然后根据充电时间裕度排序实现不同电动汽车的底层AGC功率分配。海南电网仿真算例表明:该文所提的上层分配框架可有效实现电动汽车与传统水火电机组的协调,DITL算法能有效提升AGC的动态控制性能,降低系统的调节成本。     

浙江电网AGC现状及有关问题的对策

从主站端子系统与厂站端子系统2个层次分析浙江电网自动发电控制（AGC）系统的基本配置；介绍浙江全省具备AGC功能的机组情况；从电网与发电厂2方面总结浙江电网AGC运行过程中遇到的技术、厂网协调、电网方式及负荷特性等问题，并从管理和技术等层面上提出解决现有问题和充分发挥浙江电网AGC作用的方法和建议：加强并网机组的考核管理；提高超短期负荷预测的准确性；现实水、火电AGC联合调整；合理设置AGC调节周期；优化AGC主站端控制系统。     

互联电网AGC控制研究进展

综述了互联电网AGC控制研究进展。归纳并分析了6个研究方向:基于经典控制器的结构与参数优化的AGC控制;基于模糊控制器及改进的AGC控制;基于CPS信息的AGC控制;多类型发电机组协调下的AGC控制;利用SMES的AGC控制;利用TCPS的AGC控制。     

扰动控制性能评价标准在福建电网的应用

简要介绍了华东电网正在推行的控制性能标准(control performance standard,CPS)/扰动控制标准(disturbance control standard,DCS),以及基于CPS/DCS的系统扰动控制性能评价及考核办法。提出在福建电网采用自动发电控制(automatic generation control,AGC)机组及非AGC机组按照正常速率或紧急速率自动调节,或采用人工调节相结合的DCS控制策略。建立了基于CPS/DCS的AGC控制策略中4个控制器之间的协调机制,并根据华东电网CPS/ DCS考核结果对各控制器的控制修正系数进行优化。在福建电网EMS系统中完成了DCS控制策略及AGC控制策略的功能开发,最后通过福建电网实际发生的扰动对该策略进行了验证。     

AGC协调优化策略

随着建设新能源为主体型电网目标的提出,协调新能源主要形式之一的光伏发电系统配合传统水、火电同步机组参与电网频率调节是保证电网稳定运行的必要措施。针对包含光伏以及水火机组系统的二次调频过程,综合考虑系统中火电成本及污染,水电振动区等各类型机组在AGC环节中的特点,通过基于第三代非支配排序遗传算法（NSGA-III）的多目标进化算法对各类型机组出力进行协调优化。最后,在DIgSILENT软件中,搭建了包含光伏并网系统以及调频环节的IEEE 39节点仿真系统,通过与传统比例分配策略的对比验证了所提优化策略的优越性。     

含风电的交直流互联电网自适应SPMC调频策略

大规模风电接入交直流互联电网,对自动发电控制（automatic generation control, AGC）的控制性能及调频能力提出了更高的要求。在风电参与电力系统调频的基础上,提出基于功率调制控制器(supplementary power modulation controller,SPMC)的区域间功率补偿策略。首先,考虑到高压直流输电（high voltage direct current, HVDC）环节过载率变化的弹性特征,提出一种同时考虑功率与频率变化的自适应动态SPMC策略,使其在参与系统调频时,能有效提升HVDC中功率调整的快速性;其次,在HVDC链路主动参与系统调频的基础上,考虑风电的不确定性,利用综合惯性控制改变风电输出功率,以进一步提升系统调频性能指标。仿真结果表明,所提策略的动态功率调制特性可以有效提升区域间功率传输的针对性,并提高电网调频效果。     

基于SSTLF与AGC的机组出力调度系统设计

从浙江电网实际负荷特点及浙江AGC的应用现状出发,提出了基于超短期负荷预测的机组出力调度系统的构想。该系统通过调度员的参与能够实现全网机组出力的实时合理调节,从而达到提高浙江电网守口水平的目标。文章进一步介绍了该出力调度系统的总体结构和设计方案,并介绍了目前成功应用于浙江电网的几种超短期负荷预测方法。文章认为该出力调节系统具有较强的实用性,在国内电网中具有普遍的通用性。     

新型电力系统多能源能量惯性动态优化控制模型

针对新型电力系统中大规模可再生能源并网和高比例电力电子设备的接入,导致系统惯量水平下降,影响电网安全稳定运行的问题,提出一种新型电力系统多能源能量惯性动态优化控制模型。首先,分析电力、热力、燃气的惯性特性,分别建立电力系统和热、气系统能量传递惯性模型。其次,基于多能源输运下的耦合协调关系,提出一种基于事件驱动电力、热力、燃气系统动态惯性优化控制方法。最后,建立修改的IEEE 39节点电力系统、6节点热力系统和7节点燃气系统的仿真模型进行算例仿真,仿真结果表明,所提出的控制方法能够有效改善新型电力系统的频率响应,保持系统运行鲁棒性。     

新型电力系统多能源能量惯性动态优化控制模型

针对新型电力系统中大规模可再生能源并网和高比例电力电子设备的接入,导致系统惯量水平下降,影响电网安全稳定运行的问题,提出一种新型电力系统多能源能量惯性动态优化控制模型。首先,分析电力、热力、燃气的惯性特性,分别建立电力系统和热、气系统能量传递惯性模型。其次,基于多能源输运下的耦合协调关系,提出一种基于事件驱动电力、热力、燃气系统动态惯性优化控制方法。最后,建立修改的IEEE 39节点电力系统、6节点热力系统和7节点燃气系统的仿真模型进行算例仿真,仿真结果表明,所提出的控制方法能够有效改善新型电力系统的频率响应,保持系统运行鲁棒性。     

浙江电网火电机组AGC运行状况及性能考核分析

根据浙江电网火电机组自动发电控制(AGC)的基本运行状况,叙述了电网调度对AGC作为辅助服务的性能考核计算方法,结合统计机组的运行状况和考核情况数据,针对新老两种不同考核标准,对比分析了影响机组AGC性能考核的主要因素,并提出了相应的优化方向,以期改善机组AGC性能指标及考核结果。     

提高广东电网自动发电控制应用水平的探讨

通过对广东电网自动发电控制(AGC)运行情况的分析,指出了影响AGC运行的主要原因是目前的控制方式为滞后的控制方式,适用于水电机组占较大比例的电网,而对火电机组占多数的广东电网,目前的控制方式并不能满足要求。为此,针对负荷预测和发电计划的应用,从管理和技术角度提出了水、火电协调的AGC控制方式。采用该方式可提高广东电网AGC运行水平,但具体的调节效果还有待于实际系统运行的验证。     

基于特高压和超高压直流互联的送端电网AGC系统控制策略

采用基于特高压和超高压直流的电网异步联网方式对现有的自动发电控制(AGC)系统控制策略和电网频率控制的适应性问题逐步显现.为分析直流系统异步联网方式对电网AGC系统控制策略带来的影响,结合直流系统负荷的频率静态特性及其附加频率控制器的动态特性,分析了区域电网AGC对控制区设置、控制模式选择以及与直流附加频率控制器的适应性的影响,并对目前国内广泛应用的控制性能评价标准(CPS)控制策略适应性进行探讨.基于PSD-FDS平台进行直流系统与AGC的频率控制仿真验证和实际工程应用,结果表明基于特高压和超高压直流互联的送端电网AGC控制策略能够较好地适应异步互联电网,为异步联网方式下AGC系统控制策略制定和优化提供参考.     

大型火电机组在AGC运行方式下的控制特性分析

结合华北电网自动发电控制(AGC)的实际运行情况,介绍了AGC控制方式、华北电网对AGC投运机组的控制指标要求以及机组的协调控制系统设计方案,分析了华北电网中的大型火电机组在AGC运行过程中遇到的问题,并提出了提高机组在AGC运行方式下的控制特性的方法和建议.     

TLBO optimized sliding mode controller for multi-area multi-source nonlinear interconnected AGC system

This paper represents design of output feedback sliding mode controller (SMC) for multi area multi-source interconnected power system. After designing output feedback SMC, teaching and learning based optimization (TLBO) technique is utilized to optimize feedback gain and switching vector of the controller. The superiority of the proposed approach is shown by comparing the result with output feedback tuned SMC with differential evolution and particle swarm optimization and state feedback SMC tuned with genetic algorithm for a two area thermal interconnected power system. Further, the proposed approach is extended to multi-area multi-source non linear automatic generation control (AGC) system with/without HVDC link. First area consists up thermal, hydro and gas; second area consists up thermal, hydro and nuclear as generating unit. Additionally, the superiority of proposed approach is shown by sensitivity analysis, which is carried out with wide changes in system parameters.     

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.     

宁夏多直流外送系统SSO特性分析及次同步阻尼控制器设计

针对宁夏电网近电气距离耦合的火电机群与多直流输电的简化等值送端系统,利用基于复频域端口等效导纳矩阵的复转矩系数法对其进行次同步振荡(SSO)特性分析。研究表明,降低宁夏电网直流输电外送功率,加强宁夏电网送端交流系统,增强直流换流站之间电气耦合强度等均有利于改善系统SSO阻尼特性。其次,针对存在SSO风险的灵武二期电厂机组,开展直流输电附加次同步阻尼控制器设计,并通过仿真证明了其有效性。该文研究成果可为宁夏电力外送系统的运行、规划及SSO抑制提供技术支撑和参考。     

超临界火电机组运行灵活性提升控制策略研究及应用

新能源发电装机容量和区外远距离供电量的不断增长,电网供电结构发生了根本性变化,导致调峰压力不断加大,对火力发电机组自动控制灵活性改造的要求也因此逐步提高。通过对电网AGC指令特点分析,并研究超临界火电机组的控制特性,按照电网日趋严格的调度要求,提出了提高宽负荷下机组负荷响应速率、避免AGC指令小幅波动对机组控制的影响,以及提高再热汽温控制稳定性等一系列优化策略。经过实际应用证明,优化后的协调控制系统可以在保证机组主要热力参数稳定的基础上,很好地满足电网对火电机组运行灵活性提升的考核要求。     

火电机组参与自动发电控制运行对机组寿命的影响

目前华东电网的大、中型火电机组都参与自动发电控制(AGC)运行，提高了电网的安全稳定性和电网频率的品质．但AGC产生的负荷大幅度波动对火电机组的寿命也存在一定的负面影响。计算结果表明，变负荷速率与机组寿命之间有着密切的关系，5MW／min变负荷速率升降负荷对转子的寿命损耗为3MW／min变负荷速率时的4～7倍；机组正常运行中经常出现的高频低幅的负荷波动对转子寿命的影响很小，可忽略不计。