Basic concept and decentralized autonomous control of super‐distributed energy systems

New small‐scale dispersed generation systems, such as fuel cells and micro gas turbines, have made remarkable advances lately and they will be applied practically in the near future. Although a large number of researches on the introduction of small‐scale dispersed generation systems have been carried out, only a small number of small‐scale dispersed generation systems are considered in these researches. Therefore, little is known about problems to be solved when a large number of small‐scale dispersed generation systems are introduced into electric power systems. This paper deals with a super‐distributed energy system that consists of a great number of dispersed generation systems such as fuel cells, micro gas turbines, and so on. The behavior of a customer with a dispersed generation system is simulated as the Ising model in statistical mechanics. The necessity of a distribution network in super‐distributed energy systems is discussed based on the Ising model. The feasibility of decentralized autonomous control using vicinity information is also investigated on the basis of stability analysis of the Hopfield neural network model. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 151(1): 43–55, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10368     

含异构分布式电源的微电网无功功率分散分层控制策略

无功功率—电压下垂与电压—无功功率下垂是多逆变器孤岛微网系统中两种典型的分布式电源无功控制方式。针对含异构分布式电源的微电网,提出了无功功率的分散分层控制策略:①通过改进空载电压,能够在阻抗不匹配的情况下实现无功功率的合理分配,并将公共连接点(PCC)电压恢复至额定值;②基于不同时间尺度搭建分层结构,能够满足微网静态和动态性能的需求;③摆脱传统控制中通信的制约,实现分布式电源即插即用效果。最后,小信号分析、时域仿真以及RT-LAB硬件在环仿真实验验证了控制策略的可行性和有效性。     

Autonomous decentralized voltage profile control of super‐distributed energy system using multi‐agent technology

A super‐distributed energy system is a future energy system in which a large part of its demand is fed by a huge number of distributed generators. At one time some nodes in the super‐distributed energy system behave as load, whereas at other times they behave as generator—the characteristic of each node depends on the customers' decision. In such situation, it is very difficult to regulate the voltage profile over the system due to the complexity of power flows. This paper proposes a novel control method of distributed generators that can achieve autonomous decentralized voltage profile regulation by using multi‐agent technology. The proposed multi‐agent system employs two types of agent: a control agent and a mobile agent. Control agents generate or consume reactive power to regulate the voltage profile of neighboring nodes and mobile agents transmit the information necessary for VQ‐control among the control agents. The proposed control method is tested through numerical simulations. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 164(4): 43–52, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20484     

计及分布式电源集群不确定性的配电网分散鲁棒电压控制

随着光伏、储能等分布式电源广泛接入,导致配电网区域电压波动频繁。针对分布式电源分散接入带来的不确定性问题,提出了一种计及分布式电源集群不确定性的配电网分散鲁棒电压控制方法。将大规模分布式电源聚合成相互关联的集群,对电压控制进行分区域调节。首先,针对配电网结构复杂和分布式电源点多面广的问题,设计一种基于改进Louvain算法的配电网集群划分方案,利用模块度函数并兼顾了集群的电压灵敏度和分布式电源调控容量。然后,由于分布式电源接入后配电网潮流更加复杂多变,在划分集群的基础上提出一种考虑不确定性的分散鲁棒控制方法,协同各分布式电源集群的调控能力,抑制由于模型参数及功率波动等不确定性导致的配电网电压波动。最后,通过算例分析验证了所提方法的可行性和有效性。     

主动配电网区域自适应性电压分层分区控制

针对主动配电网集中控制周期长,调节有载变压器分接头响应速度慢,难以有效地解决局部电压越限等问题,提出一种新型电压分层分散控制方法。该方法基于多代理系统架构,以分布式电源为中心将配网划分为多个随系统运行状态变化而具有自适应性的本地控制区域,充分利用分布式电源无功输出调节能力,从而实现电压分区自治控制,并且在分散控制架构下实现与传统变压器调节手段相配合的配网综合电压调控。最后基于IEEE33节点配电测试系统对所提方法的有效性进行了分析与验证。     

A study of autonomous reactive power control method for distributed power generators to maintain power quality of the grid

Distributed power generators, such as cogenerators and renewable energy systems, have continued to advance and their penetration capacity is increasing. However, they may cause power quality problems in voltage regulation because of the reverse power flow. At present, when the distribution line voltage exceeds the limit value, distributed generators control reactive power to reduce the voltage, and if the reactive power output is not enough, they reduce the active power output. Therefore, an imbalance of active power output between distributed generators may occur because the voltage of generators varies by location and generators at lower voltage locations do not control the reactive power. A power control method for distributed generators needs to be established to solve these problems. In this study, an autonomous reactive power control method of sharing reactive power between distributed generators is proposed. The availability of this method is discussed experimentally and its applicability area is considered analytically by use of a model distribution system. © 2006 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

自律分散式AVC系统在地区电网中的应用

针对传统集中式AVC系统存在的问题,结合自律分散系统的思想,提出正常情况下集中控制与故障情况下自律分散控制相结合的控制模式,构建了地区电网自律分散式AVC系统;在地区电网内部进行分区,将大规模地区电网的无功优化问题分解为若干小规模子系统的优化问题,对粒子群算法进行改进,采用多线程技术实现各区域并行计算;并结合地区电网的...     

Evaluation of the reduction in CO2 emissions by applying Micro‐Grid to home energy supply system

Dispersed generators such as wind power systems, photovoltaic systems, and cogeneration systems are expected to mitigate the environmental burden of energy consumption, and their installation has been promoted recently. Micro‐Grid is focused on as a method to solve some problems in a commercial electric power line when installing a large number of dispersed generators, and some demonstrative research on Micro‐Grid for large‐scale systems is being carried out now. Also, small cogeneration systems for houses, such as gas engines and fuel cells, are expected to improve CO₂ emissions. However, if the power and heat demand of a family are relatively small or are unbalanced, the cogeneration system does not operate effectively. The authors have studied the application of Micro‐Grid for home energy supply, and have developed a control system to solve this problem. The system achieves a reduction of CO₂ emissions and energy costs by sharing electric power and heat among some houses with cogeneration systems. This paper presents an outline of the newly developed system, and in particular describes the effect of the reduction in CO₂ emissions compared with a conventional energy supply method, and the case in which dispersed generators are installed in some houses and operate independently. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 170(3): 19–27, 2010; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20879     

并网分散电源的解列与孤岛运行

根据有功功率平衡原则、分散电源的产权关系和电气分布,提出了一种配电网分层孤岛运行的概念,可充分利用分散电源的供电能力,提高供电可靠性。接入多个分散电源的配电网络可划分为电厂级孤岛和变电站级孤岛,故障后的网络根据负荷匹配情况分层逐级解列。孤岛形成过程中,通过监测联络线的稳态功率变化计算孤岛内的功率不平衡,充分考虑孤岛的调节能力实现实时减载。最后,介绍了一种实现分层孤岛运行的分层分布式控制系统,借助高速通信网络,完成分层解列、实时减载、再同步与重合闸等功能。     

兼顾系统调频需求的分布式风电分散自治调控策略

越来越多的风力发电将分布在配电系统中,它们无法像常规电源一样由输电网调度中心集中调度和控制,通常需要采用分散自治的调控方式。然而,风电机组完全不顾输电系统的运行需求充分自治,会在某些方式下导致系统运行状态恶化。因此,需要研究风电机组新型调控策略,使充分自治转变成能够兼顾系统某些特殊运行需求的有限自治,配合系统渡过难关。针对此问题,提出了能够兼顾系统调频需求的分布式风电机组分散自治调控策略,该策略根据风电机组运行信息和系统频率将风电机组调控区划分为并网控制区、正常调控区、异常调控区、紧急调控区和脱网控制区五类,并给出了异常调控、紧急调控和故障调控三种新的调控模式。算例表明:风电机组能够较好地根据系统调频需求,在最大可用输出功率范围内调整自身输出功率,一定程度上给予系统积极的支持。     

Autonomous decentralized system for torque control of high‐power permanent magnet synchronous motor

An autonomous decentralized system (ADS) for the control of a high‐power permanent magnet synchronous motor (PMSM) presented in this paper. The system decentralizes a centralized control system into several autonomous subsystems. Thus the power supply and power electronic devices of the control system can be replaced by smaller ones, thereby obtaining better fault tolerance of the system. The subsystems are connected only through the data field, which, in this paper consists of feedback elements and communication modules. This structure enables the autonomous controllability and autonomous coordinability of the system. The mathematical model of the PMSM with decentralized stator coils is proposed. This model takes into account the self‐ and mutual inductance of the coil, as well as the effect of the stator slot‐pitch angle. In addition, an autonomous algorithm for the torque control of the PMSM with decentralized stator coils is proposed, and the fault‐tolerance design is developed. Experimental results of the torque control and fault‐tolerance control confirm the validity of the proposed system. © 2012 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

再论超高压变电站自动化系统的发展策略

通过对超高压变电站自动化系统中集中模式，相对分散模式，分层分布分散模式等主要结构模式的介绍及几个典型工程的实践经验，提出在系统集成，面向对象、标准化，通信通道，抗干扰等方面需要注意的问题，并总结了一种综合考虑了可靠性、灵活性，经济性，可维护性等因素的典型系统方案，该结构模式能够适用目前绝大多数工程的需要，同时，还对超高压变电站自动化系统的体系结构，总线结构，系统安全和通信方式等相关技术发展的新动向，以及发展超高压变电站自动化系统应采取的策略进行了探讨。     

主动配电网的分层调控体系及区域自治策略

合理的运行体系构建及分层分区调控方法,可以实现主动配电网运行过程中的主动决策、管理和控制,保证电网运行的安全性和经济性。构建了基于多时间尺度的主动配电网三层控制体系框架,提出了目标提前决策、全局集中优化、区域分散自治的分层分区协同调控方法。主动配电网的每个控制区域接受全局优化给定的计划目标,进行实时功率校准。提出扰动临界切换指标,对运行中系统受到的扰动大小进行量化,以此作为控制模式选择的依据。以馈线控制误差作为控制目标,提出短时间尺度下的功率调整策略,跟踪上层给定的全局优化目标,进行实时校正。仿真算例结果验证了不同场景下所提策略的有效性。     

An economic evaluation for an autonomous independent network of distributed energy resources

This paper proposes a method for the economic evaluation of an autonomous independent network of distributed energy resources. There are existing proposals for such networks; the system that we are proposing and analyzing in this study is called Microgrid. Microgrid is a new framework of power delivery system that is formed by small, modular generation systems connected to each other to create a small autonomous grid. This paper estimates the total costs to consumers in a Microgrid with optimized operation of distributed generators and energy storage systems. This estimation includes not only installation and operation costs but also the additional expenses to construct the Microgrid itself. In addition, power interruption costs are also taken into account to consider the reliability enhancement created by the Microgrid. The paper attempts to determine whether or not it is economical for consumers to form this kind of autonomous independent network.     

基于2层协调调度的风光储柴优化配置研究

针对风光储柴微网系统中蓄电池放电深度过大的问题,采用了2层协调调度策略。在第1层柴油发电机与混合储能的协调中,在蓄电池荷电状态达到下限之前,预先启动柴油发电机参与平衡调节;在第2层混合储能的功率分配中,基于蓄电池和超级电容器的动态特性进行功率协调分配。根据上述协调调度策略,建立了风光储柴系统的优化配置模型,采用改进的遗传算法寻求最优配置方案。通过具体算例,验证了所采用的协调调度策略的正确性和有效性。     

A local demand forecast by NN method for distributed autonomous voltage and reactive power control system

The paper describes required technological innovation for voltage control of power systems under deregulation of power supply industries and presents a new concept of an autonomous control system for the voltage and reactive power of power systems. Installation of distributed generation connected to distribution networks will significantly increase the short circuit capacity of distribution lines. Therefore, GIS underground substations in the center of a large city are required to enable replacement of circuit breakers with ones of greater capability and to reform GIS bus configurations. Furthermore, a more detailed forecast of local demand and operation data of distributed generators are required for the stable control of voltage and reactive power. This paper presents methods of on‐line autonomous forecasting for short circuit capacity and demand of local transmission and distribution lines, which are indispensable for voltage and reactive control under deregulation of electric power supply industries. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 159(4): 27–37, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20450     

直流微网中混合储能系统的无互联通信网络功率分配策略

直流微网中通常采用混合储能系统作为缓冲环节,对分布式能源和负载引起的不同时间尺度功率波动进行补偿。为实现功率在能量密度型储能元件和功率密度型储能元件之间合理分配,提出无互联通信网络的分层控制策略。其中,底层控制以电压变化率作为虚构的信息载体,通过设置不同储能接口变换器输出电压关于功率的"灵敏度",确保超级电容在负载突变瞬间能够提供大部分功率;二次控制对底层控制产生的稳态误差进行补偿,以实现输出电压稳定,并保证超级电容稳态电流为零。在此控制框架下,各储能单元仅需本地信号即可实现自主协调运行,避免了互联通信网络所带来的经济性和可靠性问题。最后,实验结果验证所提方法的可行性和有效性。     

基于连续潮流的配电网供电能力评估

随着非全相运行的分布式电源大量接入配电网,配电网固有的三相不平衡特征更加突出,传统配电网供电能力评估因忽略配电网三相不平衡特征导致结果不准确。为了准确分析三相不平衡特征对配电网最大供电能力评估的影响,建立了以配电网供电负荷参数最大为目标函数,考虑了支路热约束和节点电压等状态变量和分布式电源的有功和无功功率等控制变量的含分布式电源三相不平衡配电网供电能力评估模型。选择电压跌落情况最严重的相作为连续参数,确保预测-校正过程的的连续潮流法求解的结果更加精确。最后,采用拓展的IEEE33节点配电系统进行仿真验证,表明文中所提的模型和求解方法是有效的。     

Optimal voltage control in distribution systems using PV generators

Recently, renewable energy technologies such as wind turbine generators and photovoltaic systems have been introduced as distributed generation. The connection of large number of distributed generators causes voltage deviation beyond the statutory range in a distribution system. In this paper, a methodology for voltage control in proposed by using the tap changing transformers and the inverters interfaced with the distributed generators. In the proposed method, information of the voltage and power is collected via a communication network. Based on these information, the optimal reference values are calculated at the control center, and sent to the transformers and the inverters. The proposed method accomplishes a coordinated operation among the control equipments and reduces the voltage deviation. Effectiveness of the proposed method is verified by the numerical simulation results.     

区域自治型单相/三相多微网多时间尺度递阶控制

随着微网大规模推广应用,地域上较为相近的多类相序微网可互联形成单相/三相混联多微网系统。针对脱离配电网情况下所形成的区域自治多微网,提出一种多时间尺度集散式递阶控制策略,包括秒级分散式实时控制、分钟级集中式协调和小时级动态孤岛切换。其中,分散式实时控制基于各子微网自身稳定运行裕度实现源—荷—储功率调节,平抑光伏和负荷功率波动的同时跟踪联络线功率;集中式协调考虑分散式控制的弃光切荷量以及三相不平衡度约束,基于多目标混合整数规划实现源—荷—储集中式优化进行全局功率分配;动态孤岛切换通过组合互联方案决策实现区域多微网整体资源配置最优。经仿真实例验证,所提策略可实现单相/三相多微网多时间尺度递阶控制,实现应对源—荷波动的源—荷—储协调控制,有利于多微网离网的安全高效运行。