Distributed Control of Thermostatically Controlled Loads in Distribution Network with High Penetration of Solar PV

High penetration of solar energy can result in voltage rise in midday,while growth in residential air conditioning is the main contributor of overloading and voltage drop issues during peak demand time.This paper provides a hierarchical control scheme to coordinate multiple groups of aggregated thermostatically controlled loads to regulate network loading and voltage in a distribution network.Considering the limited number of messages that can be exchanged in a realistic communication environment,an event-triggered distributed control strategy is proposed in this paper.Through intermittent on and off toggling of air conditioners,the required active power adjustment is shared among participating aggregators to solve the issue.A case study is conducted and simulation results are presented to demonstrate the performance of the proposed control scheme.

Coordinated Control Strategy for Operation Mode Switching of DC Distribution Networks

Due to the advantages such as low line cost,low transmission loss,and high power supply reliability,DC distribution networks have become the main development trend for future distribution networks.In this paper,a typical DC distribution network with multiple voltage levels is considered as a research object.It is proposed that the interface converters between DC buses with different voltage levels be implemented through the series-parallel combination of full-bridge LLC resonant converters.To realize the decentralized self-discipline control of DC voltage under various working conditions,different slack buses are prepared according to the voltage ranges of the DC buses,and the voltage regulation modes of the DC distribution network are divided into main voltage regulation mode,backup voltage regulation mode,and off-grid voltage droop regulation mode.By introducing a voltage coefficient related to DC voltage deviation as a basis for mode switching,the voltage fluctuations caused by slow switching between control modes in the method of traditional voltage margin control is reduced,facilitating fast and smooth switching between different voltage regulation modes.Finally,a simulation model for DC distribution networks is constructed utilizing MATLAB/Simulink.Simulation results verify the effectiveness and feasibility of the proposed voltage regulation modes and switching methods for DC distribution networks.Finally,an experimental platform is also constructed to verify the feasibility of the mode switching method proposed in this paper.

Learning Reactive Power Control Polices in Distribution Networks Using Conditional Value-at-Risk and Artificial Neural Networks

Scalable coordination of photovoltaic(PV)inverters,considering the uncertainty in PV and load in distribution networks(DNs),is challenging due to the lack of real-time communications.Decentralized PV inverter setpoints can be achieved to address this issue by capitalizing on the abundance of data from smart utility meters and the scalable architecture of artificial neural networks(ANNs).To this end,we first use an offline,centralized data-driven conservative convex approximation of chance-constrained optimal power flow(CVaR-OPF)in which conditional value-at-risk(CVaR)is used to compute reactive power setpoints of PV inverter,taking into account PV and load uncertainties in DNs.Following that,an artificial neural network(ANN)controller is trained for each PV inverter to emulate the optimal behavior of the centralized control setpoints of PV inverter in a decentralized fashion.Additionally,the voltage regulation performance of the developed ANN controllers is compared with other decentralized designs(local controllers)developed using model-based learning(regressionbased controller),optimization(affine feedback controller),and case-based learning(mapping)approaches.Numerical tests using real-world feeders corroborate the effectiveness of ANN controllers in voltage regulation and loss minimization.

高比例分布式可再生能源交直流混合配电网运行调控:科学问题与技术框架

随着分布式可再生能源发电与中低压直流组网技术的快速发展,未来配电网必然向复杂的交直流混合形态演进,其运行调控技术面临许多新的挑战。在高比例分布式可再生能源交直流混合配电网(HR-HDN)运行调控技术发展需求分析的基础上,提炼出HR-HDN运行调控技术的3个科学问题,并以多类型可控设备协同、源-网-荷-储高度互动化和市场化需求为研究主线,从稳定控制、故障主动防御与恢复、电力市场机制辅助调控以及“平台+数据”数字化集成调控4个方面,提出了HR-HDN的运行调控技术框架。最后,对HR-HDN运行调控关键技术的未来发展进行了展望。

基于光伏逆变器调节的中低压配电网电压分层协调控制策略

针对高比例分布式光伏接入配电网引起的电压质量问题,提出一种基于光伏逆变器调节的中低压配电网电压分层协调控制策略。首先分析了中低压有源配电网电压控制方式,提出一种光伏逆变器电压区间分区控制方法;然后,提出了中低压配电网2阶段分层控制架构,构建以网络损耗最小、电压偏差最小和分布式电源消纳最大为目标的优化控制模型;最后,结合IEEE 33节点算例以及某实际配电网算例对有源配电网分层控制策略进行验证。IEEE33节点算例表明,优化方法可使配电网整体损耗降低3.79%,电压偏差率降低27.29%;实际配电网算例结果表明,优化方法可使配电网整体损耗降低36.33%,电压偏差率降低62.59%,并可有效提高光伏消纳平衡能力,保障有源配电网安全稳定运行。

考虑光储一体化系统柔性调节能力的配电网电压优化策略

针对高比例光伏接入城市配电网引发的电压质量问题,本文提出了考虑光储一体化系统(PIESS)柔性调节能力的配电网电压优化策略。首先,分析三种典型的“光伏+广义储能”一体化运行场景,并建立三种场景下广义储能的运行模型,进一步提出PIESS的运行模型;然后,分析PIESS的柔性调节潜力,并计算PIESS有功和无功约束的统一表达式;最后,将PIESS的运行模型及功率约束纳入配电网的电压优化模型,并处理为混合整数二阶锥规划模型进行求解。在改造的IEEE 33节点系统中验证了所提模型的调压效果,结果表明PIESS能有效改善配电网电压分布,充分利用不同类型“光伏+广义储能”的柔性调节能力能保障配电网的安全经济运行。

基于IPSO-SVC的含风电配电网稳压控制策略

当配电网含风电接入时,电能质量会受到较大的影响。为解决不同风速下风力机出力不同影响配电网电压稳定性的问题,利用静止无功补偿器提高含风电配电网电压稳定性。在考虑不同风速场景下,引入改进粒子群算法并以配电网系统有功损耗最小为目标函数,优化SVC控制参数,改善SVC对电压的控制性能。以含风电IEEE 33节点算例进行仿真计算,验证了该算法的正确性和可行性。

基于迁移学习的OMS配网瞬态稳定性控制方法

为了提升一体化控制效果,确保OMS配网的瞬态稳定,研究基于迁移学习的OMS配网瞬态稳定性控制方法。通过迁移学习调整网络中非固定层参数,依据提取的特征训练重构非固定层的网络,构建迁移学习卷积神经网络模型;输入二维电压电流数据图像,输出OMS配网瞬态稳定性预测结果;若OMS配网瞬态失稳,则求解OMS配网内发电机的灵敏度,按照灵敏度生成OMS配网瞬态稳定性一体化控制策略。实验证明,该方法在不同故障下,综合评价指标值较高,一体化控制效果较佳。

主配一体调度自动化系统优化设计方案

主配一体调度自动化系统是实现主配协同的重要技术支撑,文中基于主配一体调度自动化系统的技术发展现状及存在的问题,探讨了主配一体调度自动化系统优化设计方案,提出了实时监控主站+配网调控云主站+配网设备云主站结构,提出了主配一体调度自动化系统实用化在主站整合、网络安防、电网一张图、数据同步和数据完整性、主配协同算法等方面亟待解决的关键问题。

Integrated Distribution Management System:Architecture,Functions,and Application in China

As massive distributed energy resources(DERs)are integrated into distribution networks(DNs)and the distribution automation facilities are widely deployed,the DNs are evolving to active distribution networks(ADNs).This paper introduces the architecture and main function modules of an integrated distribution management system(IDMS)and its applica-tions in China.This system consists of three subsystems,including the real-time operation and control system(OCS),outage management system(OMS),and operator training simulator(OTS).The OCS has a hierarchical architecture with three levels,including the local controller for DER clusters,the optimization of DNs incorporated with multi-clusters,and the coordina-tion operation of integrated transmission&distribution(T&D)networks.The OMS is developed based on the geographical information system(GIS)and coordinated with OCS.While in the OTS,both the ADN and its host transmission network(TN)are simulated to make the simulation results more credible.The main functions of the three subsystems and their interaction data flows are described and some typical application scenarios are also presented.

考虑变流器无功调节特性的含高比例分布式光伏配电网电压控制方法

高比例分布式光伏接入后,配电网出现潮流随光伏出力在大小和方向上随机变化的现象,造成配电网电压大幅度波动,严重情况下电压发生越限。充分利用光伏变流器及储能变流器的无功调节潜力,能够有效应对含高比例分布式光伏配电网的电压越限问题。首先,对含高比例分布式光伏配电网的电压运行特性进行分析。然后,对变流器无功电压调节特性进行分析,研究影响变流器无功调节能力的各项约束。在此基础上,提出一种考虑变流器无功调节特性的无功自响应电压控制方法,并对该方法的无功动作阈值进行了优化整定。在该方法中,变流器将就地量测电压与无功动作阈值相比较,进行无功快速动作。最后通过仿真证明了该方法能有效解决含高比例分布式光伏配电网的电压越限问题。

配网抢修智慧指挥全流程管控系统设计

为了扩大配网抢修过程中的管控规模、降低风险和损失,设计了配网抢修智慧指挥全流程管控系统。在硬件部分,针对系统实际应用功能设计硬件整体结构,根据IEC 61850标准,利用电缆和三轴磁传感模块优化电子互感器的接口电路,以提升电流与电压信号的传输性能。在软件部分,基于多维数据云调控技术进行数据采集与融合,完成配网抢修智慧指挥全流程管控系统设计,以实现抢修看板可视化管控。测试结果表明,所提方法与理想方法之间的关联度指标优于其他对比方法。该设计可降低配网抢修风险。

基于全景物联调控模型的配网一体化负荷均衡优化控制

为了解决配网一体化中常见的馈线重过载问题,研究基于全景物联调控模型的配网一体化负荷均衡优化控制方法。利用数据层的数据读取采集不同应用系统的配网数据信息,利用数据接口转换解析所得数据,服务层通过SOAP/WSDL服务和REST服务访问数据层中的解析数据,并传输到逻辑层。采用全景物联信息一体化模块对接收到的解析数据进行融合。根据融合结果,应用层的配网一体化负荷均衡调控模块,运用基于多源数据融合的配网一体化负荷均衡优化控制方法,获得负荷均衡优化控制方案。实验结果表明:通过数据融合能很好地识别配网一体化线路风险;负荷均衡优化控制后,不同时刻的馈线负荷曲线均在馈线额定电流以下。该方法能有效降低线路损耗,提升线路的负荷均衡性。

35 kV配电网有功功率潮流调节偏差控制方法

常规的配电网有功功率潮流调节偏差控制方法忽视了无功功率潮流的补偿,降低了潮流调节偏差控制效果。因此,设计了35 kV配电网有功功率潮流调节偏差控制方法。首先,通过控制发电设备的出力可以实现对有功功率的调节。根据系统负荷变化情况,调整发电设备的出力可以使得系统的有功功率匹配系统负荷需求,进而修正潮流调节偏差。其次,通过改变变压器分接头的选取,可以调整变压器的输出电压,从而使得潮流在配电网中的分布更加均衡。同时,通过在配电网中采用HHUPFC控制器,可以补偿潮流中的无功功率,提高系统的功率因数,进而改善潮流分布和降低潮流调节偏差。针对35 kV配电网的特点,该方法还采用单独调节配电网首端电压幅值、线路电抗和首末端相位差等措施。通过分别调节这些参数,可以精确控制潮流的分布,使得潮流调节偏差得到有效控制。通过对比实验验证,该方法在潮流调节偏差控制方面具有更佳的效果。

基于当前智能电网模式的配网调控一体化分析

在整个国家电网的运营和管理过程中,最广泛应用的电网系统之一是智能电网,智能电网系统早已逐步深入影响社会生活。为此,需要持续更新原来的电力系统,使电力系统在智能电力系统中得到充分利用,确保智能电力系统的高效运转。着重分析和讨论了智能电网中配网调节整合的相关内容,以期为今后配网调节整合提供参考。

Robustness analysis and distributed control of a networked system with time-varying delays

This paper is concerned with the robustness analysis and distributed output feedback control of a networked system with uncertain time-varying communication delays.This system consists of a collection of linear time-invariant subsystems that are spatially interconnected via an arbitrary directed network.Using a dissipation inequality that incorporates dynamic hard lQCs(integral quadratic constraints)for the delay uncertainties,we derive some sufficient robustness conditions in the form of coupled linear matrix inequalities,in which the couplld parts reflect the interconnection structure of the system.We then provide a procedure to construct a distributed controller to ensure the robust stability of the closed-loop system and to achieve a prescribed lzgain performance.The effectiveness of the proposed approach is demonstrated by some numerical examples.

适应光伏高比例接入配电网变流器的控制技术研究

文章探讨光伏系统高比例接入配电网时所需的变流器控制技术,分析配电网的基础接入技术,构建光伏并网模型,并针对高比例接入的特点,提出包括模糊控制、神经网络控制、预测控制、自适应控制以及分布式控制的控制技术,旨在提高系统的稳定性和效率,保证电能质量。通过搭建仿真环境进行仿真验证,结果表明这些控制技术能有效地支持高比例光伏接入,确保配电网的稳定运行。

Design and analysis of control system using neural network for regulated DC power supply

Conventional control systems used for regulated power supplies,including the proportional integral and derivation(PID)controller,have some serious disadvantages.The PID controller has a delayed feedback associated with the control action and requires a lot of mathematical derivations.This paper presents a novel controlling system based on the artificial neural network(ANN),which can be used to regulate the output voltage of the DC power supply.Using MATLABTM,the designed control system was tested and analyzed with two types of back-propagation algorithms.This paper presents the results of the simulation that includes sum-squared error(SSE)and mean-squared error(MSE),and gives a detailed comparison of these values for the two algorithms.Hardware verification of the new system,using RS232 interface and Microsoft Visual Basic 6.0,was implemented,showing very good consistency with the simulation results.The proposed control system,compared to PID and other conventional controllers,requires less mathematical derivation in design and it is easier to implement.

调控一体化下的配电网自愈研究

自愈是智能配网调控一体化最核心的内容。结合国内外智能配网建设实践,对智能配网调控一体化的概念和内容给出新定义,对配网自愈功能的含义、特征进行阐述。在此基础上提出自愈系统的一种分模块设计思路,对其实现方法进行了探讨。强调自愈控制系统在实现自愈过程中占据重要地位,对其按功能进行层次划分,并提出各层次如何分工协作实现控制。提出了评价配网自愈能力的参考指标项,包括自愈时间和自愈率等。指出在自愈控制系统中应用先进的电力电子技术是未来的发展方向。

基于光伏逆变器功率协调控制的电压调节方法

分布式光伏的大量接入会引起接入点出现过电压问题,对逆变器的功率进行控制可以达到调节电压的目的,为此,在深入研究有功功率抑制(active power curtailment,APC)调压方法和Q(U)与Q(P)等调压方法的基础上,提出了一种协调控制区域内各逆变器输出功率的电压调节方法。该方法将APC与无功功率控制的方法相结合,考虑到各分布式光伏电源之间的协调,采用集中控制的思想,建立典型的约束优化数学模型,使用复合形算法优化求解各逆变器的有功和无功功率指令值,以此保证线路上各节点的电压在规定范围内。最后建立典型的低压配电网模型,对比现有Q(U)和Q(P)控制策略,验证了该方法的优越性。