Electrical characteristics of new three-phase traction power supply system for rail transit

A novel three-phase traction power supply system is proposed to eliminate the adverse effects caused by electric phase separation in catenary and accomplish a unifying manner of traction power supply for rail transit.With the application of two-stage three-phase continuous power supply structure,the electrical characteristics exhibit new features differing from the existing traction system.In this work,the principle for voltage levels determining two-stage network is dissected in accordance with the requirements of traction network and electric locomotive.The equivalent model of three-phase traction system is built for deducing the formula of current distribution and voltage losses.Based on the chain network model of the traction network,a simulation model is established to analyze the electrical characteristics such as traction current distribution,voltage losses,system equivalent impedance,voltage distribution,voltage unbalance and regenerative energy utilization.In a few words,quite a lot traction current of about 99%is undertaken by long-section cable network.The proportion of system voltage losses is small attributed to the two-stage three-phase power supply structure,and the voltage unbal-ance caused by impedance asymmetry of traction network is less than 1‰.In addition,the utilization rate of regenerative energy for locomotive achieves a significant promotion of over 97%.

Modeling and optimization of a multi-carrier renewable energy system for zero-energy consumption buildings

For the carbon-neutral,a multi-carrier renewable energy system(MRES),driven by the wind,solar and geothermal,was considered as an effective solution to mitigate CO2emissions and reduce energy usage in the building sector.A proper sizing method was essential for achieving the desired 100%renewable energy system of resources.This paper presented a bi-objective optimization formulation for sizing the MRES using a constrained genetic algorithm(GA)coupled with the loss of power supply probability(LPSP)method to achieve the minimal cost of the system and the reliability of the system to the load real time requirement.An optimization App has been developed in MATLAB environment to offer a user-friendly interface and output the optimized design parameters when given the load demand.A case study of a swimming pool building was used to demonstrate the process of the proposed design method.Compared to the conventional distributed energy system,the MRES is feasible with a lower annual total cost(ATC).Additionally,the ATC decreases as the power supply reliability of the renewable system decreases.There is a decrease of 24%of the annual total cost when the power supply probability is equal to 8%compared to the baseline case with 0%power supply probability.

Optimisation of Electrical Distribution System by Using Solar Thermal Powered Systems and Its Impact on Electrical Distribution Feeders

In this research, the performance of the solar thermal powered systems (STPS) is analyzed with different models (without inserts, with inserts and with Nano fluids with different concentrations) and its impact on the Electric load in a residential/Institutional Electrical Distribution system. For this purpose, the electrical and solar thermal water heater is tested and validated. Solar thermal powered systems and its impact on the Institutional electrical distribution feeders are tested and compared with the energy efficiency (EE) and cost optimization. The goal of this paper is to analyze the impact of solar thermal energy on electrical energy consumption in the electrical distribution feeder level. The electrical system cost and energy consumptions are tabulated and observed that there is a considerable savings.

Parametric optimization of power system for a micro-CCHP system

The universal mathematical model of an engine is established,and an economical zone,in which an engine mainly provides medium output load at medium speed,is presented.Based on the experimental data and the universal model of such an engine above,a mathematical model of a refitted engine is provided.The boundary of the corresponding economical zone is further demarcated,and the optimal operating curve and the operating point of the engine are analyzed.Then,the energy transforming models of the power system are established in the mode of cooling,heating and power（MCHP）,the mode of heating and power（MHP）and the mode of electricity powering（MEP）.The parameter matching of the power system is optimized according to the transmission ratios of the gear box in the power distribution system.The results show that,in the MCHP,the speed transmission ratio of the engine to the gear box（ies）and the speed transmission ratio of the motor to the gear box（ims）are defined as 2.9 and 1,respectively;in the MHP,when the demand load of the power system is less than the low critical load of the economical zone,the speed transmission ratio of the motor to the engine（ime）is equal to 1,and when the demand load of the power system exceeds the low critical load of the economical zone,ime equals 0.85;in the MEP,the optimal value of ims is defined as 2.5.

One Step on the Smart Grid Path： Load and Generation Coordination in a Virtual Power System

Worldwide the introduction of dispersed generators （DG） in the distribution network is assuming a significant importance. There is an increasing relevance of the energy process efficiency improvement; as for electric power systems, the most interesting perspective concerns the capability of the system to increase the exploitation of the renewable resources. The integration of DGs in the electric distribution network requires a revision of this infrastructure, so far designed and developed assuming that power flows in one direction： from the high voltage transmission network to the medium voltage distribution, to reach final customers on the low voltage network. The attention to an efficient operation of distribution networks is increasing all over the world; this interest is becoming higher and higher also in Italy, where the high energy prices push in the direction of fostering efficiency as much as possible. This work describes a study developed in the AlpEnergy project framework： an International Cooperation Program aimed at introducing an efficient operational model for the distributed production and consumption. In particular it is proposed a new model for the integration and the management of the DG in the distribution network. The new model （defined VPS： Virtual Power System） is based on a communication channel between the active users （generators）, the loads and, eventually, the Distribution System Operators （DSOs）.

“工业上楼”建筑电气设计要点浅析

随着经济的发展,城市产业发展往往面临产业转型升级加速和土地资源紧张的双重压力,“工业上楼”举措成为了当今城市产业发展的趋势和研究方向。“工业上楼”面向的产业类型较多,不同产业类型对电气设计的需求也不同,因此“工业上楼”建筑电气设计也相对复杂,对电气设计也带来一定挑战。本文将针对“工业上楼”建筑电气设计关键要点进行探索,以供参考。

国家区域医疗中心武汉协和重庆医院电气设计要点

以国家区域医疗中心华中科技大学同济医学院附属协和医院重庆医院(一期工程)为例,对医疗建筑电气设计的以下问题进行分析与探讨:供配电系统设计的变压器安装容量合理性分析、供配电系统可靠性分析、变压器能效等级选择及机房选址等;针对医疗建筑的电能质量问题提出解决方案;调研同类医疗项目存在的照明光环境问题,设计本项目的物联网智能照明光环境系统;总结本项目光储直柔微网系统设计要点。

分布式储能在成都科幻馆的应用

通过电化学储能在2023年第81届世界科幻大会主场馆——成都科幻馆项目的示范应用,重点从应用场景、并网接入电压、接入系统方案、运行策略等方面分析用户侧分布式储能在民用建筑的应用要点。

基于多传感器数据自动融合的配电房能耗远程监控系统

为了全面、准确地监测配电房能耗,设计了基于多传感器数据自动融合的配电房能耗远程监控系统。硬件上,采用A1101R04C霍尔传感器、DC 0~20 V电压传感器、SINAEX P530功率传感器及DHT11温湿度传感器设计传感器模块,并选择STM32F407ZGT芯片作为微处理器。软件上,采集配电房传感器监测数据,基于多传感器数据自动融合算法进行不同传感器监测数据的融合,获取配电房能耗监控结果。结果表明,配电房能耗远程监控数据的误差在±1%范围内,具有较高的监测精度和稳定性。

风光火储联合供应火电厂厂用电系统优化调度

随着风电和光伏发电量逐年增长,其消纳问题日益凸显。同时,大容量火电机组厂用电负荷也相对较高,造成额外的运行成本。对此,基于多能互补思想,建立了一种风光火储联合供应火电厂厂用电优化调度模型。首先,提出了风光火储联合供应火电厂厂用电的组成结构,将风电、光伏发电优先供应厂用电负荷;其次构建了风光火储联合供应火电厂厂用电优化调度模型,考虑了火电机组不同负荷率下的运行成本和风光储成本,采用层次分析法建立了基于总成本、弃风弃光成本和环境成本的多目标函数,设置相应约束条件;最后,设置不同的场景对比分析联合供应厂用电系统的优化结果,试验结果表明:所提出的联合供应厂用电系统模型可以减少机组运行成本和环境成本,并促进风光消纳。

含分布式能源配电网中考虑供电可靠性的混合储能优化配置

针对分布式能源(DERs)接入对配电网供电可靠性带来的不确定性问题,提出了计及供电可靠性的配电网混合储能系统(HESS)优化配置双层模型。首先,提取了5种负荷用户典型负荷时序曲线和风电、光伏机组典型出力时序曲线,并且基于序贯蒙特卡洛法建立了考虑DERs孤岛、HESS随机故障及运行策略的配电网供电可靠性仿真模型;其次,针对配电网故障情况下HESS运行优化问题,提出故障停电场景下HESS多目标优化配置双层模型以及考虑HESS容量分点和功率分点的充放电策略。最后,以改进IEEE-31节点系统进行算例验证,结果显示所提模型可使配电网综合供电可靠性提升0.118%,且DERs消纳量显著提高30%以上。

新能源预测纳入备用对平衡和消纳的影响研究

高渗透率新能源深刻影响了日前电力平衡模式,新能源纳入日前电力系统备用面临高峰电力平衡不确定性增大、保供与新能源消纳统筹难度增大等问题。为此,综合分析了新能源纳入日前电力系统备用比例与电力保供、新能源消纳的关系。首先,研究了新能源纳入比例与电力保供的关系,提出了基于保供可靠性的新能源纳入比例上限的数学解析公式,进一步分析了影响新能源纳入比例上限的关键因素;然后,研究了新能源纳入比例与新能源消纳的关系,提出了基于消纳需要的新能源纳入比例下限的数学解析公式;最后,基于新能源纳入比例上、下限,提出了一种用以量化反映电网保供和消纳难度的综合指数。实例分析及应用验证所提方法的科学性和实用性。

燃料电池分布式供能技术发展现状及分析

燃料电池发电技术具有高效率、低污染、低噪声等特点,且易与碳捕集技术结合实现CO_(2)近零排放,已成为分布式供能领域的关键技术与重要方向。该文介绍燃料电池分布式供能技术的特点、种类及应用,总结国内外燃料电池分布式供能技术的政策规划和技术发展现状,探讨我国在燃料电池分布式供能领域技术发展趋势。预期未来我国以氢气和天然气为主要燃料类型的质子交换膜燃料电池(proton exchange membrane fuel cell,PEMFC)和固体氧化物燃料电池(solid oxide fuel cell,SOFC)技术将得到广泛应用,而应用于社区、医院、学校等大型公共场所的热电联供系统将是近期更易实现商业化的方向。最后,针对我国燃料电池分布式供能技术的开发推广,指出我国未来发展需综合考虑经济性和安全性,重点突破燃料电池关键技术的国产化,并完善燃料电池分布式供能的补贴政策和技术标准,进一步推动其产业化应用。

含分布式光伏的主动配电网供电能力自适应优化研究

为实现电网供电能力最大化,提出含分布式光伏的主动配电网供电能力自适应优化方法。构建配电网供电能力相关指标评估模型,建立最大年消纳能力计算模型,同时构建供电能力评价模型,获取实时供电能力效果;依据配电网供电的相关参数,构建配电网线路规划模型并求解,得到最大供应能力,实现主动配电网供电能力自适应优化。实验结果表明:在场景1和场景2中,所提方法得到了不同的配电网开关设备配置方案,最大供电量稳定在63 MW和80 MW,能够提升至少25%的供电能力;经过线路规划后,变电站建设数量大幅度减少,最多为5个,使投资成本减少43%以上。

储能/发电机级联式供电系统功率传输控制策略

随着可再生能源渗透率的不断提升,区域电网惯性逐步降低,暂态支撑能力严重不足,给电网带来了一系列安全问题。文中提出一种储能与开绕组永磁同步发电机(open-winding permanent magnet synchronous generator,OW-PMSG)级联供电的新型分布式并网发电拓扑,在保证可再生能源消纳的前提下,重新利用原有柴油机,为电网提供功率后备以及惯量支撑。通过对OW-PMSG进行建模以及系统功率流矢量分析,设计基于源网相位差闭环控制的功率传输策略,实现发电机的稳定同步运行。基于该策略,拓扑中的储能变流器可具备同步发电机特性,实现了电网惯性和暂态支撑能力的进一步提升。仿真结果验证了所提控制策略的有效性。

含储能和分布式光伏的配电网系统计及静态电压稳定性的多目标优化

提出一种含储能电池和分布式光伏电源的配电网系统多目标优化模型,用以应对光伏电源发电的不确定性和间歇性造成的配电网系统静态电压稳定性降低、电压越限、网损增大等问题。考虑24 h的小时级光伏出力及负荷变化,除以节点电压偏差最小和网损最小为目标外,优化目标还着重考虑静态电压稳定性指标和电压越限惩罚。基于粒子群算法,以IEEE 33节点配电网系统作为基础算例模型,通过优化储能电池的充放电功率及有载调压变压器、并联电容器组和静止无功补偿器等无功补偿装置,利用储能电池和无功优化装置的协同调控,实现配电网系统的24 h动态优化。优化结果表明所提出的优化方案能明显增强配电网系统的静态电压稳定性,减小电压偏差和网损,防止节点电压越限,为配电网系统的安全经济稳定运行提供保障。

多代理技术在Energy Hub中的应用研究

微电网的分布式特点对系统的运行控制带来新的机遇和挑战,多代理系统(MAS)在微电网中的应用是目前研究的热点。在微电网中引入了一个新的概念——Energy Hub,构建并阐述了一个基于多代理系统(MAS)的三层控制体系。该体系依靠一定的经济运行策略,可以解决微电网系统的优化运行问题。

基于动态组网的园区微电网群运行优化

为提升园区微电网群运行经济性、供电可靠性和新能源消纳能力,提出了一种基于动态组网的园区微电网群运行优化方法。首先以运行成本、负荷损失成本和弃光成本最小为目标构建线性化微电网群组网模型,以便利用线性求解方法高效求解;其次考虑到某一时刻多个微电网可能会同时出现功率超额或缺额情况,为确定最优组网方式,提出了一种基于微电网互联约束条件的最优组网方案选择方法;最后采用一个包含3个微电网的园区微电网群系统进行算例测试,结果验证所提方法能够实现微电网间动态连接,提升微电网群运行经济性,减少负荷损失提升系统供电可靠性,提升新能源就地消纳能力。

月球科研站建设初期的能源系统设计

随着中俄关于合作建设国际月球科研站谅解备忘录的签署,月球科研站的建设已被正式提上日程。针对月球科研站建设初期,月面支持设备少,可靠性要求高,需具备后期扩展能力等任务特点,从母线体制设计、供电系统设计及配电系统设计出发,提出了一种双母线体制下基本构架一致,独有功能选配的能源系统设计方案,可适用于构建科研站基本型的所有航天器。同时对方案中需要突破的可靠性提升及关键性能提升这两大类技术进行分析,给出未来的研究方向,为后续月球科研站基本型建设过程中能源系统研究和设计提供了参考。

基于V2G潜力模糊评估与移动储能协调调度的灾后供电恢复策略

目前用户侧电动汽车(EV)等新型应急资源尚未形成系统化调配机制。对此,提出一种考虑EV与电网互动(V2G)潜力模糊评估与移动式储能协调调度的灾后供电恢复策略。在固定式可调配能源有限的前提下,将V2G加入配电网孤岛主动划分与移动式储能对电能的时空转移协调调度过程中,建立孤岛间的能量连接,保证供电连续性与稳定性。考虑主客观影响因素,运用模糊模型评估EV响应潜力,引导EV集群参与供电恢复,提高可调度容量利用率。结合配电网运行约束,建立以停电损失与恢复资源调度成本最小化、电动汽车聚合商收益最大化为目标的灾后恢复模型,兼顾电网侧、电动汽车聚合商、用户的利益,降低灾后停电损失。设立评估指标,在仿真算例中验证所提策略的有效性与经济性。