提高关键负荷供电可靠性的交直流微网分布式能量优化管理策略

交直流混合微电网具有较高的灵活性和可控性,能够为多种类型的分布式电源提供并网接口。然而,交直流微网中可再生能源占比较高,容易出现出力波动或出力不足等现象,难以保障关键负荷可靠供电;此外,交直流微网中分布式电源可能从属于不同运营主体,相互之间缺乏有效的信息交换,集中式管控较为困难。为此,提出提高关键负荷供电可靠性的交直流微网分布式能量优化管理策略,构建了微网分布式能量优化管理架构,建立以考虑微网负荷优先级的供电可靠性为优化目标、考虑各设备运行约束的能量优化管理模型,提出基于分布式模型预测控制的能量优化管理策略,并通过分布式次梯度算法求解。多个场景下的仿真分析表明,所提方法不仅可平抑可再生能源波动对负荷供电的影响、保障关键负荷的供电可靠性,还能有效保护微网设备隐私信息、满足交直流微网多运营主体环境下的负荷供电可靠性需求。     

集中控制式微网系统的稳态建模与运行优化

包含多种分布式能源和可控负荷、作为一个可控整体的微网具有灵活的运行方式和可调度性能,既可与主网并网运行,也可以孤岛形式自主运行.在建立各种分布式能源稳态模型的基础上,建立了集中控制模式下的微网优化调度模型,提出了运行和折旧成本最低、环境和综合效益最高等优化目标函数.以一个微网系统为例,讨论了所采用的交互式运行控制策略、优化目标函数以及主网电价类型的不同对系统运行优化结果的影响,验证了所建立的模型的合理性.     

含多能微网群的区域电热综合能源系统分层自治优化调度

分布式能源与负荷聚合形成多能微网群连接至区域供热系统和上级配电网,构成区域电热综合能源系统.为保护多利益主体隐私并满足其利益诉求,提出了基于分布自治、集中协调设计架构的区域电热综合能源系统分层优化调度方法.在上层,计及多能流异质动态特性,提出了区域电热综合能源系统的动态经济调度模型;在下层,考虑用户柔性热需求和分布式光伏不确定性,建立了多能微网自治能量管理的机会约束模型.基于目标级联分析法将上下层解耦,层间仅需交换边界电功率和热功率,通过微网并行计算与层间迭代求解获得全局最优策略.算例结果证明,该方法能够在保证收敛性的前提下,为含多能微网群的区域电热综合能源系统提供高精度的多能互补优化调度结果.此外,对缩放因子进行灵敏度分析,讨论了算法误差来源并说明了算法最优性.     

基于一致性的微网分布式能量管理调度策略

基于多智能体一致性理论,设计了具有完全分布式特征的微网能量管理调度策略,以解决集中式控制方式通信压力大和无法满足即插即用要求的问题。以可控发电单元和储能单元运行成本最低为目标函数,结合微网功率平衡和发电单元出力的约束条件,建立了分布控制式微网最优经济调度模型。根据多智能体及一致性理论设计了微网的分布式能量管理调度算法,给出了该方法的具体实施步骤。通过在IEEE-14节点微电网系统中的仿真算例,验证了所提出调度策略的正确性和有效性。     

基于分布式模型预测控制的综合能源系统多时间尺度优化调度

采用具有滚动优化、反馈校正特点的模型预测控制是实现综合能源系统多时间尺度优化调度的关键技术之一.鉴于集中式模型预测控制实现系统整体在线优化的复杂性,文中提出一种基于分布式模型预测控制的综合能源系统多时间尺度优化调度方法,通过各子系统协调配合实现综合能源系统灵活调度.首先,建立以系统日运行经济最优、系统日运行费用及机组启停惩罚费用最小为目标的日前、日内滚动优化模型.然后,在实时阶段采用基于分布式模型预测控制的优化调度策略对整体优化问题进行分解,各子系统根据其他子系统前一时刻的输入序列进行状态估计并优化自身性能指标.最后,通过对各子系统的协调控制进而实现整个系统的在线优化,满足其动态调整需求.仿真结果表明,所提方法能够在改善系统控制性能的同时,提高系统运行的经济性.     

基于库存理论考虑局部不确定性的互联微电网分布式鲁棒调度

为实现广域分布式能源系统的高度自治性和鲁棒性,提出了一种用于互联微电网(interconnected microgrids, IMG)的分布式鲁棒经济调度(distributed robust economic dispatch, DRED)。首先,应用多智能体理论搭建IMG的分层分布式调度框架;其次,为了解决分布式鲁棒优化问题,将原问题分解为多层问题,在上两层进行可行性测试和联络线功率优化。在此研究结果的基础上,运用库存理论对可再生能源和负荷的不确定性进行了研究;最后,以一个实际的IMG系统为例,通过对分散和集中式鲁棒方案的比较,验证了该策略的收敛性和可行性。该模型在计算复杂度上也优于传统的DRED模型,利用概率信息实现了某一置信水平下的最优调度。     

Multi-agent system for energy resource scheduling of integrated microgrids in a distributed system

This paper proposes a multi-agent system for energy resource scheduling of an islanded power system with distributed resources, which consists of integrated microgrids and lumped loads. Distributed intelligent multi-agent technology is applied to make the power system more reliable, efficient and capable of exploiting and integrating alternative sources of energy. The algorithm behind the proposed energy resource scheduling has three stages. The first stage is to schedule each microgrid individually to satisfy its internal demand. The next stage involves finding the best possible bids for exporting power to the network and compete in a whole sale energy market. The final stage is to reschedule each microgrid individually to satisfy the total demand, which is the addition of internal demand and the demand from the results of the whole sale energy market simulation. The simulation results of a power system with distributed resources comprising three microgrids and five lumped loads show that the proposed multi-agent system allows efficient management of micro-sources with minimum operational cost. The case studies demonstrate that the system is successfully monitored, controlled and operated by means of the developed multi-agent system.     

Blockchain for decentralized transactive energy management system in networked microgrids

The proliferation of distributed energy resources is reshaping the landscape of power distribution systems, including a network of autonomous microgrids. Networked microgrids transact energy for managing the efficiency, reliability, resilience, security, and sustainability of electric power services. This article offers a vision and analyzes a scheme developed for networked microgrids that utilizes blockchain technologies to optimize the financial and physical operations of power distribution systems. Blockchain provides a powerful and trustworthy path for launching distributed data storage and management, the article explores the possibility of customizing blockchain technologies to meet socioeconomic requirements of transactive energy management at the power distribution level. Then, a set of interoperable blockchains embedded with self-enforcing smart contracts is proposed to manage energy and financial flows among transacting microgrids in a credible manner. The article presents additional smart contract measures for securing optimal energy transactions between networked microgrids and the local distribution grid. It is concluded that blockchain technologies embedded in transactive energy will play a significant role in the evolution of traditional power distribution systems to active distribution networks.     

基于鲁棒随机模型预测控制的园区综合能源系统两阶段优化

可再生能源发电与负荷的不确定性给园区综合能源系统的安全准确调度带来了巨大挑战,为了提高系统调度的准确度和运行经济性,提出了一种基于鲁棒随机模型预测控制的两阶段优化调度策略.该模型考虑到园区综合能源系统中负荷预测误差分布的规律性和可再生能源出力波动的概率分布难以准确刻画的特点,分别利用随机优化和鲁棒优化处理负荷侧和发电侧...     

基于多场景随机规划和MPC的冷热电联合系统协同优化

以包含可再生能源及多种分布式资源的区域冷热电联合系统为研究对象,针对风光和负荷的不确定性,提出多场景随机规划结合模型预测控制(MPC)的方法,建立多时间尺度协调优化模型,其中日前和日内尺度主要以运行经济性最优为目标,求解机组的运行及出力计划;实时尺度采用模型预测控制技术,以日内尺度经济调度结果为参考,通过反馈校正与滚动优化调整机组运行出力,实现机组出力的精确控制,消除可再生能源波动性影响,并进一步讨论了出力扰动对调度结果的影响。算例分析证明所提模型和方法能够有效消除不确定性和风光波动性的影响,实现多能源互补协调优化运行。     

A review of decentralized and distributed control approaches for islanded microgrids: Novel designs,current trends,and emerging challenges

Distributed energy resources (DER) on the demand side have been fast growing, which could boost energy resilience by uninterruptedly supplying the commercial and residential sectors in the form of islanded microgrids when the utility electricity grid is out of service. Nevertheless, simply applying the centralized hierarchical control strategies, traditionally used for utility electricity grids, onto the islanded microgrids would encounter several critical issues. For instance, the control goals in secondary and tertiary control could be activated tardily, the single-point fault could cause critical system failure, and the properties of dynamic plug and play would be hard to achieve. To this end, decentralized and distributed control approaches have been explored to cope with the issues. Specifically, compared to the centralized hierarchical control, decentralized and distributed control strategies can (i) respond to disturbances more promptly, enhancing the performance of islanded microgrids with limited resources; (ii) guarantee system stability especially when a fault occurs and certain DERs are disconnected from the network; and (iii) facilitate deeper penetration of DERs in the microgrid, owning to the low computational complexity and sparse communication network. In this article, the common approaches for decentralized and distributed control are reviewed, and the current design trends and critical technical challenges are discussed to offer a comprehensive understanding of decentralized and distributed controlled microgrids.     

电—气互联综合能源系统多时间尺度动态优化调度

对于时空相关的天然气管存,应用多时间尺度/模型预测控制尤为重要。计及天然气管网的慢动态特性,考虑暂态天然气系统变量存在时段耦合的特性,提出了基于模型预测控制的多时间尺度优化调度策略,使机组有功出力和气源产气控制过程更为平滑。其中,以日前优化调度得到的有功出力值和产气量为参考值,基于模型预测控制,进行日内多时段滚动优化。最后,对修改的IEEE 24节点电力系统和比利时20节点天然气系统进行算例分析,验证了所提优化调度方法的可行性以及有效性,并分析了气网管存对电—气互联综合能源系统运行的影响。     

A Dual-loop Model Predictive Voltage Control/Sliding-mode Current Control for Voltage Source Inverter Operation in Smart Microgrids

Abstract

The design of a robust controller for the voltage source inverter is essential for reliable operation of distributed energy resources in future smart microgrids. The design problem is challenging in the case of autonomous operation subsequent to an islanding situation. In this article, a dual-loop controller is proposed for voltage source inverter control. The outer loop is designed for microgrid voltage and frequency regulation based on the model predictive control strategy. This outer loop generates reference inverter currents for the inner loop. The inner loop is designed using a sliding-mode control strategy, and it generates the pulse-width modulation voltage commands to regulate the inverter currents. A standard space vector algorithm is used to realize the pulse-width modulation voltage commands. Performance evaluation of the proposed controller is carried out for different loading scenarios. It is shown that the proposed dual-loop controller provides the specified performance characteristics of an islanded microgrid with different loading conditions.     

A Hybrid Agent-based Model Predictive Control Scheme for Smart Community Energy System with Uncertain DGs and Loads

A multi-agent consensus-based market scheme is proposed for the cooperation of community and multiple microgrids (MGs) in a distributed, economic and hierarchal manner. The proposed community-based market framework with frequency regulation (FR) market is formulated as a two-level scheduling problem: the global decision-making process of community agent (CA) to participate in the FR market and the interaction and control process of local MGs to achieve collaboration in response to the global target with efficient pricing rules. Specifically, the model predictive control (MPC) is integrated with the consensus-based theory to allow MG to obtain an economic and reliable dispatch in the presence of uncertainties of distributed generators and loads. Thanks to the distributed nature of the proposed scheme, its robustness to communication issues has been strengthened and a win-win situation for all energy stakeholders can be achieved. The robustness of the proposed scheme is investigated in various conditions, including different implementation strategies, communication topologies, and the level of uncertainties.     

电力市场环境下虚拟电厂两阶段能量经济优化调度

随着分布式可再生能源在电网中的渗透率不断增加,虚拟电厂作为一种高效管理分布式可再生能源的技术已经引起国内外学者的广泛关注。提出一种非管制电力市场环境下的虚拟电厂两阶段能量经济优化调度方法,该方法将虚拟电厂的调度分为日前和日内2个阶段。在日前阶段,基于预测信息制定次日的最优调度计划并与日前电力市场签订协议;在日内阶段,以日前计划为参考,采用模型预测控制策略调整日内的运行计划,以消除由于预测误差导致的净负荷波动,同时尽可能减少来自日内平衡市场的罚款,降低总体运行成本。所提出的模型均使用商业求解器Gurobi进行求解。仿真数值结果表明：所提出的算法通过日前计划和日内调控的手段提高了可再生能源设备的利用率,具备一定的经济性和实用性,为虚拟电厂的经济调度提供了新的思路和途径。     

Optimal hoist scheduling of a deep level mine twin rock winder system for demand side management

This paper presents a near optimal hoist scheduling and control program for rock winders found in South African deep level mines in the context of demand side management and time-of-use (TOU) tariffs. The objective is to achieve a set hoist target at minimum energy cost within various system constraints. The development of a discrete dynamic and constrained mixed integer linear programming model for a twin rock winder system is presented on which a half-hourly model predictive control (MPC) algorithm containing an adapted branch and bound methodology is applied for near optimal scheduling. Simulation results illustrate the effectiveness of the control program by minimising the energy costs through scheduling according to the TOU tariff and controlling output and ore levels within their boundaries even in the case of significant random delays in the system. Scheduling according to the TOU tariff shows a possible 30.8% reduction in energy cost while approximately 6 h of delays in the system resulted in a mere 14% increase in energy cost.     

智能电网中清洁分布式能源的优化利用策略

智能电网是全球经济和技术发展的必然结果。为此,分析了智能电网中清洁能源大量使用的发展趋势,同时借助微电网模式对分布式能源进行管理,研究了智能电网中分布式能源最优化利用问题。提出了基于多代理系统(MAS)的控制框架。为了优化利用分布式能源,设计了协调控制策略。详细分析了各Agent的控制方法。MAS实现了对全网清洁分布式能源信息化、智能化的控制。仿真结果验证了MAS能够快速有效地对全网各电源进行协调控制,保证了各种状态下系统的安全稳定以及对清洁分布式能源的最优化利用。     

基于模型预测控制的智能楼宇用能灵活性调控策略

提出一种基于模型预测控制的智能楼宇用能灵活性调控策略。首先,根据楼宇蓄热特性,构建考虑楼宇内部不同制热区域的智能楼宇能耗预测模型,并将楼宇系统作为灵活可控单元集成到配电网中;然后基于模型预测控制方法,通过楼宇内部暖通空调系统在温度舒适度范围内对室温进行优化调节,实现楼宇系统的能耗灵活管理,降低楼宇运行成本;最后,在冬季制热场景下,对不同暖通空调控制方法下的楼宇集群进行优化调度分析,并对比分析了楼宇集群优化调度对于配电网运行状态的影响。结果表明,所提方法在保证温度舒适度的前提下可充分发掘智能楼宇的需求响应潜力,降低楼宇运行成本,同时可有效解决由可再生能源出力预测数据误差而导致的楼宇日前调控方案与实际运行场景偏差较大的问题,在预测不确定性环境下具有较强的鲁棒性。     

考虑能源效率的综合能源系统多目标优化调度

为提高综合能源系统的能源利用效率,提出一种考虑能效的多目标优化模型与求解方法.首先,分析影响综合能源系统的能源流动环节效率的因素.然后,以运行成本最低为目标建立经济性目标函数,以能源利用效率最优为目标建立能效目标函数,采用加权系数法将多目标优化转化为单目标优化.最后,采用模型预测控制进行优化调度,设立仅考虑单一目标与考...     

考虑通信时延的直流微电网分布式储能单元协调控制

针对计及通信时延的直流微电网分布式储能系统多储能单元之间的协调问题,提出了一种模型预测控制策略。首先搭建多储能单元状态空间模型,设计多储能单元的模型预测控制及其电流期望轨迹。然后分析计及通信时延的一致性规律,补偿时延引起的荷电状态偏差。进而通过求解以快速跟踪电流动态期望值及控制信号变化最小为目标函数的最优解,保证系统直流母线电压稳定,实现各储能单元间协调稳定运行以及基于荷电状态的动态一致均衡。最后利用Matlab/Simulink仿真平台,验证所提控制策略在计及通信时延的情况下储能充、放电过程以及源、荷波动下的有效性和稳定性。