基于中心地理论的充换电服务网络布局研究

将中心地理论引入电动汽车充换电服务网络规划,根据充电设施服务能力划分充换电服务网络层次结构,提出了充换电服务网络的空间结构图和充换电服务半径计算方法.     

电动汽车充换电设施典型设计方案研究

为规范充换电设施建设规模和站体布置,研究了电动汽车充换电设施标准化问题,提出了典型设计方案。阐述了典型设计方案编制原则,给出了服务对象具体参数和典型设计方案分类,举例对充电站典型设计方案进行分析研究,包括总平面布置、充电设备、供配电系统、二次系统、土建、消防等内容,并从电池架充电、分箱充电机选型及组柜、换电设备设计、换电监控、电池检测维护等五方面详细阐述换电系统设计方案。提供了所有典型设计方案的配置情况。该典型设计方案可用于统一设备类别和选型,有效控制充换电设施工程造价,也为后续充换电设施运行维护取费标准作好准备,已成功用于指导国家电网公司系统各单位编制充换电设施项目建设方案。     

电动汽车换电站设计模型的建立与优化

在全球能源问题越来越严峻的情况下,电动汽车的发展已经上升为国家战略,电动汽车换电设施是发展电动汽车所必须的重要配套基础设施。紧密结合唐山北郊电动汽车换电站项目建设,研究换电站系统的工程设计计算模型和方法,对影响工程规模和运行经济性的主要参数:换电需求量、换电设计能力、换电工位数量、充电工位数量等进行工程建模优化分析计算;在理论分析计算的基础上,形成换电站的充换电系统标准建设方案,为本地区后续换电站的建设提供参考依据。     

基于车辆时空状态链的电动汽车充换电需求模型

随着电动汽车普及,充换电设施网络整体规划建设已成为电动汽车产业发展的重要环节。整体考虑充电需求与换电需求,提出一种基于出行时空状态链的电动汽车充换电需求模型。首先,通过分析车辆行驶与停留多状态间相互转换过程,定义车辆出行时间链与空间链的特征量,并设计车辆状态转移矩阵。然后根据多种充换电模式,以及温度对单位里程耗电量影响,构建电动汽车充换电需求模型。最后,提出基于自适应混合细菌觅食算法,计算车辆处于充电需求时,多种充电模式选取情况。算例分析表明,该模型可以准确模拟用户出行规律,体现电动汽车在行驶与停留多状态下的充换电需求时空分布特点。     

基于闭环供应链的集中性充–换电系统运营优化

为提高充电站运营的经济性和电网接纳电动汽车充电的积极性,提出集中性充–换电系统的运营优化方案。在设计供应链时,采用C型闭环供应链,明确了系统运营经济性、电网影响与运营计划间的关系;在运营优化时,基于用户行为特性、电池充电特性和计及配送周期的配送模型,以用户的换电需求、充电设施和负荷峰值等为约束,通过优化站内电池的接入充电计划,实现负荷波动的平抑和电池数量的减少;随后提出适用于电池接入优化的约束多目标整数差分进化算法。并与非控制充电、填谷充电、其他算法、不同配送计划和负荷曲线下的结果进行对比,验证了所提出模型和算法的有效性和适用性。     

基于不同购电模式相结合的电动汽车充换电站运营模式研究

电动汽车达到一定规模后可能带来大量充电负荷,为使收益最大,提出充换电站应采用充电与换电相结合的工作方式,充電模式采用直接从电厂购电,而换电模式通过电网购电。以充换电站的运营收益最大为目标,结合了合同电价与市场电价之间的联动模型对该工作模式下的充换电站运营进行了经济效益分析,确定了最佳充换电比例。最后针对某地区充换电站运营进行了算例分析,证明了此方法的可行性。     

基于互联互通的电动汽车充电设施标准优化设计

作为服务电动汽车发展的基础性设施,充电设施是电动汽车规模化应用的重要保障。按照系统、通用、高效和兼容的设计思路和原则,通过研究充电接口、通信协议及充电系统的关键技术,结合充电设施建设运行的实践经验,在物理尺寸、电气性能、防护等级和主动监测等方面对原有标准进行优化设计,极大提升了充换电设施的安全性、兼容性和可靠性。新标准为充电设施的建设运营提供了技术保障,已全面应用于国内充换电设施产业,助力充电基础设施互联互通。     

电动汽车充换电设施接入电网典型模式

结合电动汽车发展及其充换电设施的建设情况,分析了电动汽车接入对配电网的影响,并从电压等级选择、用户等级确定、接入点选择、供电电源配置、设备选型和电能质量要求等方面,提出了电动汽车充换电设施接入电网的技术原则,最后给出了电动汽车充换电设施接入的典型模式,为指导规划设计、规范运行管理,保障充换电设施及时可靠、合理有序地接入提供重要依据。     

“充电”OR“换电” 利益左右下的暗战

中国新能源汽车发展究竟是采用充电模式还是换电模式,争论从2008年国家大力扶持新能源汽车产业起就没有停过。近期,国务院正式公布的《节能与新能源汽车产业发展规划(2012—2020年)》中明确提出:"积极推进充电设施建设",而对换电模式只是简单提及"探索新能源汽车及电池租赁、充换电服务等多种商业模式,形成一批优质的新能源汽车服务企业"。专家分析认为,这是对新能源汽车充换电模式发展在政策上的一锤定音,换电模式实际上已经被边缘化。这一结果对于换电模式的拥护者来说是始料未及的。     

电动汽车充换电设施与低压电器

分析了电动汽车充换电设施涉及的电工领域,概括了电动汽车充电设施对低压电器的要求,总结了低压电器在4种充电模式下的应用及适用于4种充电模式的剩余电流保护电器(RCD)的发展动态。     

电动汽车接入电网的影响与利用

未来电动汽车(plug-in electric vehicle,PEV)的大规模接入,将给电力系统规划和运行带来不可忽视的影响。从电动汽车充电负荷建模与仿真计算、电动汽车接入对电力系统的影响、电动汽车的充放电控制与利用3大方面,讨论电动汽车接入电网的研究现状。指出电动汽车充电负荷分析应考虑的主要因素;总结电动汽车接入对电源发展、电网运行、充电设施与配电网规划方面的影响,并分析电动汽车有序充电及与电网互动(vehicle to grid,V2G)的研究现状和应用难点。最后,对今后的研究方向进行讨论。     

基于双层优化的电动汽车充放电调度策略

大量电动汽车无序充放电会给电力系统的安全与经济运行带来严重的负面影响。为避免这一问题,引入了对电动汽车进行分层分区调度的理念,并构建了基于双层优化的可入网电动汽车充放电调度模型。在上层模型中,通过优化各电动汽车代理商在各时段的调度计划(包括充电负荷和放电出力),使系统在研究时间区间内总负荷水平的方差最小化,从而实现削峰填谷;在下层模型中,通过各电动汽车代理商对其所管辖电动汽车充放电时间的优化管理,以便与上层的调度计划尽可能一致。之后,采用AMPL/IPOPT和AMPL/CPLEX高效商业求解器对上下层问题分别进行迭代求解。最后,以包含5个电动汽车代理商的、修改的IEEE 30节点测试系统为例,说明了所提出的模型与方法的基本特征。     

Multi-objective optimal charging of plug-in electric vehicles in unbalanced distribution networks

Plug-in electric vehicles (PEVs) as new generations of transportation systems have recently become a promising solution to mitigate emissions of greenhouse gases produced by petroleum-based vehicles. Existing power systems may face serious reliability and power quality problems in supplying emerging PEV charging loads unless the charging task is coordinated. In addition, in real world applications, most PEVs are single-phase loads supposed to be charged from residential or commercial outlets. In this paper, a multi-objective optimization framework is proposed to optimally coordinate the charging of single-phase PEVs with dynamic behavior in unbalanced three-phase distribution systems employing smart grid facilities. Objective functions include total cost of purchasing energy in a multi-tariff pricing environment as well as grid total energy losses over charging span. The objective functions are optimized subject to network security, power quality, and PEV constraints. Fuzzy memberships are used to transform differently-scaled objective functions into a same range in order to ensure the Pareto optimality of the multi-objective solution. The proposed method is tested on an unbalanced three-phase distribution system and obtained results, which are discussed in detail, confirm its efficiency in getting a solution satisfying both objective functions as well as in the speed.     

风电电动汽车协同利用对电网风电接纳能力的影响

建立包含电动汽车充、放、耗电约束的风电电动汽车协同利用模型,根据决策变量的不同将充放电模式分为自由充电、不含V2G(Vehicle to grid)和含有V2G的风电电动汽车协同利用。以风电利用率和风电在电网能源结构中电量占比作为衡量水平,分析不同充电模式、电动汽车数量和风电装机容量下的风电接纳能力。含有V2G的风电电动汽车协同利用能够最大限度提高电网风电接纳能力,且在风电装机容量较大时更能显示出含有V2G的协同利用充放电模式的优势,含有V2G的风电电动汽车协同利用是实现大规模风电并网的有效方式,同时一定负荷和风电装机水平的电网存在一个最佳匹配的电动汽车数量。     

Fuzzy Reliability Assessment of Distribution System with Wind Farms and Plug-in Electric Vehicles

Abstract

The equipment failures are highly uncertain in nature and simple average failure rate will not reflect this uncertainty. The uncertainty level further increases in reliability evaluation due to the integration of wind farm (WF) because of the intermittent nature of wind speed and random charging patterns of plug-in electric vehicles (PEVs). In this work, the uncertain variables in the distribution system (failure rate, repair time, WF output, PEVs charging and system load factor) are represented as fuzzy numbers to handle the uncertainty. The available uncertain data are used to find the probability distribution function (PDF) of that parameter and is converted into fuzzy membership function using transformation techniques. Failure rate of equipment is converted into failure probability using Monte Carlo simulation (MCS) method. Sampling method is applied to create the PDF of a variable which has average value. Fuzzy severity index (FSI) is proposed to find the importance of an equipment on reliability and is evaluated by measuring the fuzzy distance between the fuzzy reliability indices. The proposed assessment method is validated on modified RBTS bus 2 by comparing with analytical and MCS methods. The proposed method has been tested with integration of WFs and PEVs.     

风电电动汽车协同调度对电网的影响

建立包含风电功率和电动汽车充电功率在内的机组组合模型,分析电动汽车自由充电、延迟充电和智能充电三种充电模式下的电网运行经济性、电网风电接纳能力,并利用清洁发展机制(CDM)中计算电量边际排放因子(OM)的"简单OM"方法计算不同充电策略下的碳减排效益。     

Multi-agent approach to modeling and simulation of microgrid operation with vehicle-to-grid system

This study presents the modeling and simulation of a vehicle-to-grid (V2G) system within a microgrid considering the requirements of various components of the microgrid system such as distributed renewable energy resources (DERs), plug-in electric vehicles (PEVs) and non-PEV loads. The system modeling is carried out using an agent-based methodology where components of the microgrid are modeled as agents. The use of PEV car batteries collectively as a virtual power plant (VPP) enables PEVs to not only act as loads but as energy sources alongside DERs such as wind and solar power generation. The smart control and scheduling of the charging and discharging of the PEVs by the charging station can be used to achieve sustainable integration of a high number of PEVs in the microgrid power system. In addition to simulating a microgrid operation, results of this study show how agents’ behavior change based on factors such as penetration of renewable energy, penetration of PEVs, travel pattern of PEV drivers and price of energy generation.     

An adaptive supervised wide-area backupprotection scheme for transmission linesprotection

Background: The increasing penetration of a massive number of plug-in electric vehicles (PEVs) and distributed generators (DGs) into current power distribution networks imposes obvious challenges on power distribution network operation. Methods: This paper presents an optimal temporal-spatial scheduling strategy of PEV charging demand in the presence of DGs. The solution is designed to ensure the reliable and secure operation of the active power distribution networks, the randomness introduced by PEVs and DGs can be managed through the appropriate scheduling of the PEV charging demand, as the PEVs can be considered as mobile energy storage units. Results: As a result, the charging demands of PEVs are optimally scheduled temporally and spatially, which can improve the DG utilization efficiency as well as reduce the charging cost under real-time pricing (RTP). Conclusions: The proposed scheduling strategy is evaluated through a series of simulations and the numerical results demonstrate the effectiveness and the benefits of the proposed solution.     

A fast time-frequency response baseddifferential spectral energy protection ofAC microgrids including fault location

Background: The increasing penetration of a massive number of plug-in electric vehicles (PEVs) and distributed generators (DGs) into current power distribution networks imposes obvious challenges on power distribution network operation. Methods: This paper presents an optimal temporal-spatial scheduling strategy of PEV charging demand in the presence of DGs. The solution is designed to ensure the reliable and secure operation of the active power distribution networks, the randomness introduced by PEVs and DGs can be managed through the appropriate scheduling of the PEV charging demand, as the PEVs can be considered as mobile energy storage units. Results: As a result, the charging demands of PEVs are optimally scheduled temporally and spatially, which can improve the DG utilization efficiency as well as reduce the charging cost under real-time pricing (RTP). Conclusions: The proposed scheduling strategy is evaluated through a series of simulations and the numerical results demonstrate the effectiveness and the benefits of the proposed solution.     

考虑风电波动性的微网中电动汽车分布式协调运行方法

随着风力发电的快速发展,间歇性风电引起的电网功率波动问题日益凸显,而通过制定插入式电动汽车（plug-in electric vehicles, PEVs）的合理充放电策略,可为平衡功率波动和调节系统频率提供有效支撑。文章针对含风电的微网功率波动问题,提出了基于电动汽车参与意愿度和效用函数最大的PEVs协调运行模型,并基于一致性理论设计了PEVs分布式充放电控制方法。所提方法以完全分布式方式最优调整PEVs充放电功率,可有效平抑风电功率波动,并能满足PEVs日常多种充电场景需求,包括PEVs随机到达时间和启程时间、电池荷电状态随机初始值和目标值。最后通过含有5个风电场和2 000台PEVs的微网进行验证,仿真结果表明所提PEVs协调运行模型和分布式控制方法可灵活满足规模化PEVs的充放电需求,并可有效改善微网系统的频率响应特性。