分散模糊负荷频率控制器的优化设计

本文针对多区域互联电力系统的特点，建立了一个考虑各区域扰动影响的综合性能指标，并对比例因子采用智能调整措施，提出了一种分散模糊负荷频率控制器的优化设计方法，对一个两区域互联电力系统的数字仿真结果表明，所设计的分散模糊负荷频率控制器具有良好的控制效果和较强的鲁棒性。     

含风光水火储的多区域互联电力系统协同优化负荷频率控制

针对现代电力系统中呈现出的互联和多源的特点,首先提出了一种启发式智能优化算法辅助含风光水火储的多区域互联电力系统协同优化负荷频率控制方法,该方法以每个区域的区域控制偏差为目标函数;然后利用鲸鱼智能优化算法鲁棒性强、求解精度高及收敛快速度等优点,对各区域的PID负荷频率控制器参数进行协同优化,使得系统在各种随机扰动下,都能够维持频率稳定和长期安全运行;最后建立含风光水火储的三区域互联电力系统模型,对比不同优化整定方法下的互联电力系统频率和联络线功率偏差,测试系统在不同扰动时各区域的稳定性及所提方法的有效性。实验结果表明,所采取的多区域互联负荷频率控制器协同优化整定方法有效地改善了系统的稳定性,具有良好的鲁棒性和实用性。     

云模型理论在互联电力系统负荷频率控制中的应用

针对负荷频率控制系统具有不确定性问题,提出一种基于云模型理论的多区域互联电力系统负荷频率自适应PI控制方法。该方法以区域控制偏差量e作为云模型发生器的前件,PI控制器参数的整定值P和I作为云模型发生器的后件,建立适于负荷频率控制的一维云模型PI控制器。同时分别从频域和时域角度模拟不同情况下的负荷扰动,采用云模型控制器对PI控制器参数自调整,实现电力系统的负荷频率控制。仿真结果表明,在满足各种负荷扰动情况下,所提方法可有效地跟踪功率波动所引起的频率偏差,满足负荷频率控制指标,具有更强的抗干扰性和鲁棒性,其控制效果明显优于传统PI控制器。     

MIMO伺服补偿分散控制原理在互联电力系统负荷频率控制中的应用

本文应用极点位移的方法,对互联电力系统的负荷频率控制(LFC)问题,设计了多输入一多输出(MIMO)伺服补偿分散控制器;并以一个两地区互联电力系统的实例,考察了这类控制器对地区系统频率f_i和联络线交换功率P_(tie,ij)对于给定值的跟踪效果。数字仿真的结果表明:由于伺服控制器对各地区系统的频率偏移Δf_i进行了二次积分,所以当电力系统中出现缓慢持续上升(或持续下降)的负荷扰动时,各地区发电量亦随之相应变化,使各地区系统频率偏移Δf_i经一定时间后到达零稳态。这类控制器同PI控制一样,易于实现,而控制效果更好。     

SSSC在互联电力系统负荷频率控制中的应用

建立了两区互联电力系统模型,分析了静止同步串联补偿器(SSSC)负荷频率控制的原理.SSSC频率控制器采用一阶控制环节,并通过超前滞后补偿进行校正.对两区互联系统线性化处理推出系统的状态方程,利用重叠分解对系统进行解耦求得控制系统阻尼比来设计SSSC频率控制器的目标函数,并通过改进遗传算法对控制器参数进行优化.仿真结果...     

基于粒子群算法的含大规模风电互联系统的负荷频率控制

以含大规模风电的互联电力系统为研究对象,以抑制风电并网时所引起的系统频率不稳定为目的,提出了基于PSO的负荷频率控制器。传统的负荷频率控制器根据区域控制偏差来调整机组的出力,使区域控制偏差ACE趋于零,从而保证全系统发出的出力和负荷功率相匹配。把风电输出当作一个负的负荷作为等效负荷,在传统的比例积分控制器中引入PSO智能控制,可以进一步提高对等效负荷的控制效果。通过在Matlab/Simulink中构建的含风电的两区域互联电力系统的仿真结果表明,无论是互联电网的频率偏差还是联络线的交换功率,控制指标更优。     

互联电力系统负荷频率分散次最优输出控制

本文探讨了一种适用于多区域互联电力系统负荷频率分散控制的设计方案。其中包括分散等值模型的辨识、新的最优输出控制方法的应用和一种循环设计方法。设计方案克服了以往分散等值模型不考虑外区域控制作用所带来的缺陷,取得了较满意的控制效果。     

基于变论域模糊逻辑的互联电力系统负荷频率控制

随着风电在电力系统中的渗透率不断提高,其出力不确定性对系统频率稳定造成威胁。针对风电接入系统后的频率波动问题,提出变论域模糊PI负荷频率控制策略。为克服传统模糊控制器由于论域固定导致自适应能力有限的缺点,设计的变论域模糊PI负荷频率控制器通过变论域方法实现输入、输出论域的动态调整。为满足风电接入系统后复杂的论域调整需求,基于模糊推理设计新型变论域伸缩因子。典型两区域互联系统仿真实验表明,在不同形式的扰动下,该新型控制器较PI控制器、模糊PI控制器有更好的控制表现,能更好地处理风电出力不确定性对互联电力系统频率稳定的影响。     

Fuzzy电压调节器的一种自动设计方法

将Ｆｕｚｚｙ控制表用一个带修正因子的数学式表达，利用优化方法提出了一种Ｆｕｚｚｙ电压调节器的自动设计方法。对一个单机－无穷大系统的数字仿真结果证明了新提出方法的实用性和有效性。     

计及时延的互联电力系统分散式阻尼控制

针对广域互联电力系统的低频振荡问题,计及信号在广域控制回路中的时延,设计了一种分散式阻尼控制器。首先定性分析了广域控制回路中的信号时延特点,然后在计及时延的互联电力系统线性化模型基础上,使用时延依赖稳定性充分条件进行控制器的求解,最后进行了两区四机系统分散式阻尼控制器设计。在固定时延与随机时延情况下系统仿真结果表明所设计分散控制器能够有效提高系统阻尼,抑制系统低频振荡,提高互联电力系统的动态稳定性能。     

Optimal variable structure controller for the load-frequency control of interconnected hydrothermal power systems

A new approach is presented for the load-frequency control of interconnected power systems using the theory of variable-structure systems and linear optimal control theory. A systematic procedure for the selection of the switching hyperplane, which is of vital importance in the design of variable-structure controllers, is developed by minimizing a performance index in the sliding mode operation. The proposed control scheme is illustrated by digital simulation of an interconnected power system consisting of a hydro power plant and a steam power plant.     

微粒群优化负荷频率控制

针对两区域电力系统运用微粒群优化算法进行负荷频率控制,将模糊控制和微粒群优化算法相结合,利用微粒群算法优化模糊控制规则和PI控制器参数,以实现对控制规则的自调整,并在负荷频率控制中引入模糊决策控制,以减弱由时延引起的系统振荡。对两区域的负荷频率控制系统用MATLAB软件进行仿真,并将其与传统的积分控制和模糊自调整PI控制进行比较,仿真结果表明该方法的有效性,对复杂的非线性电力系统能取得良好的控制效果。     

基于CPS考核标准的专家控制器的设计及其在负荷频率控制中应用

针对CPC控制性能标准存在的不足,本文在对NERC所采用的CPS新标准的研究的基础上,对大区域互联电网中的负荷频率控制采用了专家PID控制器的设计。专家的规则主要由两部分组成,一部分来自于对CPS标准的分析和实践经验,另一部分则是根据PID控制器的动态特性并结合负荷频率控制的实际情况获得。鉴于控制过程是一两区域的互联电网模型,因此首先对系统进行了鲁棒性分析,在此基础上应用分散控制对系统进行专家控制器的设计。通过仿真实验表明:专家经验和知识应用,提高了系统负荷频率控制的品质,在专家规则中适当引入CPS考核标准的要求,在一定程度上可以提高整个电网CPS/DCS的合格率,并且能够减少发电机组不必要的磨损。     

An Evaluation of Different Controllers Based on the Network Frequency Maintenance Strategy for a Large and Multi-control-area Interconnected Power System

Abstract—Maintaining the network frequency at its nominal value due to the load changes is one of the most important issues in the control and operation schedule of a large and multi-area interconnected power system. For the effective control solution, two types of tie-line bias control strategy-based controllers have been applied, i.e., classical and improved controllers. The classical controllers using conventional regulators, including integral, proportional–integral and proportional-integral-derivative, have achieved initial control results to bring the steady state back to the network. However, due to the very poor control features (e.g., large overshoots and long settling times), they need to be replaced with improved controllers, such as fuzzy logic and artificial neural network. To obtain an entire evaluation of the application of different load-frequency controllers, a five-control-area interconnected power system was built as a typical case study. Three improved controllers using proportional-plus-integral-based fuzzy logic and artificial neural network-based non-linear autoregressive moving average (NARMA-L2) architectures as well as their hybrid combination will also be investigated in this study. Simulation results obtained reveal that the improved controllers have obtained smaller overshoots (from 13.95 to 84.18%) and shorter settling times (from 19.91 to 65.71%) compared with the classical controllers.     

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。     

Enhancement of interconnected power system stability using a control strategy involving static phase shifters

The static phase shifting transformer is one of the potential options of the recently proposed FACTS (flexible AC transmission systems). Promising results have been obtained for enhancing the small-disturbance and the transient stability of interconnected power systems.

In this paper, the important concept of involving in the same control strategy both generating units and static phase shifters has been considered. A systematic procedure for designing co-ordinated and decentralized controllers of these components is provided to assure a satisfactory dynamic performance of an interconnected power system under both small and large perturbations. The approach uses optimal control theory as a basis for the co-ordination of static phase shifter and governor controllers. A suboptimal decentralized control scheme is derived from the designed optimal controller by using a ‘minimum norm’ nearness criterion. The resulting feedback control signals for each generating unit and for each phase shifter is expressed in terms of measurable and local variables only.

Test results show the effectiveness of the proposed control strategy and the usefulness of control actions on static phase shifters.     

多馈入交直流输电系统的模糊控制器协调优化算法

设计了一套阻尼区域间功率振荡的模糊控制器。在多馈入交直流输电系统的直流功率控制系统和发电机励磁系统中同时采用了该模糊控制器,并对影响其性能的关键参数进行了协调优化。为了解决优化结果容易限于局部最优的问题,采用了遗传算法进行全局并行寻优,同时引入序优化理论在概率意义上保证优化解的质量。仿真结果表明:与常规阻尼控制器相比,模糊控制器能更好地提高交直流互联系统的动态稳定性且具有鲁棒性。序优化遗传算法比传统遗传算法具有更稳定的性能,可作为多馈入交直流输电系统的模糊控制器参数协调优化的一种有效方法。     

Decentralized bounded input bounded output stabilization of perturbed interconnected time-delay power systems with energy storages

This paper presents a new decentralized bounded input bounded output (BIBO) stabilization problem for a class of interconnected time-delay systems and its application to power systems with energy storages. We first provide conditions for the derivation of an ellipsoid that bounds a given linear functions of the state vector. Then, a design procedure is proposed to synthesize decentralized static output feedback controllers. The designed controllers guarantee that a given linear functions of the state vector, starting from any initial condition, converges exponentially to its prescribed zones. To deal with the time-delay issue, we use an improved weighted integral inequality recently reported in the literature to derive less conservative exponential stability conditions. Then, our presented control approach is applied to an interconnected power system integrated energy storages with multiple time delays. We synthesis decentralized static output feedback load frequency controllers to guarantee that the system frequency and interchanged power converge to their prescribed zones exponentially from any initial conditions. The controller’s construction is simpler and easier for implementation due to only the local output measurements are required. In order to systematically obtain the controller gains, an effective procedure using linear matrix inequality based stabilisation criteria, which can be solved by various computation tools, is provided. Finally, the effectiveness of the proposed control scheme is verified by comprehensive simulations.     

Delay-independent decentralized stabilizer design for large interconnected power systems based on WAMS

Recent stabilizer design using wide-area measurement systems (WAMS) signals has been suggested to enhance the dynamic performance of large interconnected power systems. However, there is an unavoidable delay involved before these signals are received at the stabilizer site. Long time-delay may be detrimental to system stability and may degrade system performance. Therefore, the delay-independent robust control problem of large interconnected power systems based on WAMS is studied via H_∞ fuzzy control method. First, a set of equivalent Takagi–Sugeno (T–S) fuzzy model is employed to represent the large interconnected power systems. A wide-area state feedback decentralized control scheme is developed to stabilize the T–S fuzzy systems without any wide-area signals delay information such that the H_∞ performance is achieved. The H_∞ fuzzy robust control design problem is parameterized in terms of a linear matrix inequality (LMI) problem, and the LMI problem can be solved very efficiently using the convex optimization techniques. Finally, the performance of the robust control is studied using a fourteen-machine interconnected power system example.