Supply modes for renewable-based distributed energy systems and their applications:case studies in China

Distributed energy systems(DES),as an integrated energy system with coupled distributed energy resources,have great potential in reducing carbon dioxide emissions and improving energy efficiencies.Considering the background of urbanization and the energy revolution in China,the study investigates the renewable-based DESs supply modes and their application in China.A new method is proposed to classify DESs supply modes into three categories considering the renewable resource in domination,and their application domains are discussed.A comprehensive model is given for economic and environmental evaluation.Typical case studies show that the renewable-based DES systems can supply the energy in a cost-effective and environment-friendly way.Among them,the biomass waste dominated supply mode can not only achieve"zero"carbon emissions but also"zero"energy consumption,even though not yet economically attractive under the present policy and market conditions.Thus,recommendations are given to promote the further deployment of renewable-based DESs,regarding their supply modes,policy requirements,and issues to be addressed.

Review of Modeling Methods of Distributed Energy Supply System Connected to the Grid

At present, the development of distribution network can’t meet the requirements of rapid economic development. The traditional single energy supply is difficult to meet the request, and distributed energy supply has a lot of advantages compared to it, particularly it's close to the end users, and they have been developed well and applied widely in recent years. This paper summarizes the features and current development of the distributed energy supply, and mainly describes the grid-connection model of distributed energy supply. Base on the mathematic grid-connection model of distributed power sources with different generation principles as well as that energy storage, the treatment of these models in distribution network power flow analysis is also presented.

Optimal Simulation of Distributed Generation System for CO_2-Reduction in Supermarket and Restaurant

After the great east Japan earthquake in 2011, Japanese energy system has been expected to prioritize safety and trustworthiness. Now, distributed power systems are considered as one solution, but utilizing exhaust heat is an important task to be solved. The purpose of this study is to build a simulation model to harness waste heat of commercial buildings. We obtained two types of data： distributed power system in 1/15 scale model of supermarket, restaurant and real world energy consumption of the two buildings. Results showed cold cabinets, whose electricity was affected by temperatures outside and inside, consumed most in supermarket. While air conditioning, affected by air enthalpy of outside and inside, consumed most in restaurant. According to our simulation with gas engine, PV （photovoltaic） panel, PCM （phase change material）, thermal storage, FCU （fan coil unit） and refrigerated cabinets in scale model, we could reduce 27% of CO_2 emission and 25% of running cost by selecting optimal size.

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。

Data-driven Predictive Voltage Control for Distributed Energy Storage in Active Distribution Networks

Integration of distributed energy storage(DES)is beneficial for mitigating voltage fluctuations in highly distributed generator(DG)-penetrated active distribution networks(ADNs).Based on an accurate physical model of ADN,conventional model-based methods can realize optimal control of DES.However,absence of network parameters and complex operational states of ADN poses challenges to model-based methods.This paper proposes a data-driven predictive voltage control method for DES.First,considering time-series constraints,a data-driven predictive control model is formulated for DES by using measurement data.Then,a data-driven coordination method is proposed for DES and DGs in each area.Through boundary information interaction,voltage mitigation effects can be improved by interarea coordination control.Finally,control performance is tested on a modified IEEE 33-node test case.Case studies demonstrate that by fully utilizing multi-source data,the proposed predictive control method can effectively regulate DES and DGs to mitigate voltage violations.

Dependence of single event upsets sensitivity of low energy proton on test factors in 65 nm SRAM

In order to accurately predict the single event upsets （SEU） rate of on-orbit proton, the influence of the proton energy distribution, incident angle, supply voltage, and test pattern on the height, width, and position of SEU peak of low energy protons （LEP） in 65 nm static random access memory （SRAM） are quantitatively evaluated and analyzed based on LEP testing data and Monte Carlo simulation. The results show that different initial proton energies used to degrade the beam energy will bring about the difference in the energy distribution of average proton energy at the surface and sensitive region of the device under test （DUT）, which further leads to significant differences including the height of SEU peak and the threshold energy of SEU. Using the lowest initial proton energy is extremely important for SEU testing with low energy protons. The proton energy corresponding to the SEU peak shifts to higher average proton energies with the increase of the tilt angle, and the SEU peaks also increase significantly. The reduction of supply voltage lowers the critical charge of SEU, leading to the increase of LEP SEU cross section. For standard 6-transitor SRAM with bit-interleaving technology, SEU peak does not show clear dependence on three test patterns of logical checkerboard 55H, all＂ 1＂, and all ＂0＂. It should be noted that all the SEUs in 65 nm SRAM are single cell upset in LEP testing due to proton＇s low linear energy transfer （LET） value.

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%.

Study on operation strategy and load forecasting for distributed energy system based on Chinese supply-side power grid reform

This study focuses on the development and analysis of a real-time updated operations strategy of a distributed energy system(DES).Owing to the relevant Chinese policy of electrical transmission and distribution,combined cooling,heating,and power system(CCHP)and photovoltaic(PV)systems are not currently allowed.However,with the Chinese supply-side power grid reform,the permissions for connections between DESs and utilities are gradually evolving.By performing building simulation and using mixed integer linear programming(MILP),a real-time updated operation strategy of a DES is established.Then,considering the DES from Tianjin Eco-city as a case study,a comparative analysis between this updated strategy and the current operation strategy is performed by evaluating three factors:economic efficiency,energy consumption,and CO2 emission.The results show that the updated strategy can reduce 29.12%of electricity time-of-use cost,10.11%of total fuel consumption,and 18.40%of CO2 emission during the cooling season.Besides,a method of“rolling load forecasting”for DES by using Support vector regression machine(SVR)is proposed and discussed.The testing shows that the Mean Absolute Percentage Error(MAPE)is below 7.5%.And when the training sample is large,the particle swarm optimization algorithm can be used to shorten the modeling time of the air conditioning load forecasting model.

“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。

考虑分布式电源的配电网灾中-灾后两阶段协同韧性恢复决策

频繁的极端自然灾害极易引发配电网大规模故障,基于分布式电源的负荷恢复是提高配电网韧性水平的重要手段。然而,现有研究一般将灾中和灾后阶段进行独立决策,忽略了二者决策的连续性和耦合性,延缓了恢复进程。为此,文中提出一种基于灾中-灾后两阶段协同决策的配电网快速恢复方法,充分考虑灾中-灾后过程中的相互作用,综合分布式电源调度、网络拓扑改变、维修人员调度等在内的恢复措施,保障灾中-灾后阶段连续决策的最优性。首先,考虑灾后供能路径对灾中网络拓扑的需求关系,建立灾中阶段以分布式电源为核心的拓扑调整模型与负荷元胞恢复模型,实现部分重要负荷的供电;其次,考虑灾中决策对灾后恢复的影响,建立灾后阶段故障维修人员调度和负荷快速恢复的联合决策模型,实现所有负荷的有序恢复;然后,以灾中-灾后全阶段失负荷量最小为目标,实现灾中-灾后恢复的协同决策;最后,基于IEEE 123节点配电系统验证了所提模型的有效性。

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。

基于Floyd算法的5G基站区域储能分配策略

由于5G集中在人群密集区域配置,需要的基站数量多且能耗大,因此,运营商需要支付的购电成本很多。为了降低运营商的购电成本,本文提出一种基于Floyd算法的5G基站区域储能分配策略。首先,将供电网络中的5G基站区域储电站等效为一系列节点,并根据节点之间的距离信息计算出传输损失率矩阵;其次,对各节点的储能情况进行分析,并根据其储能情况将节点分为供能节点与需求节点;最后,基于Floyd算法来合理调配该储能网络中的能量。仿真结果表明,在不引入外部供电和引入外部供电两种情况下,本文所提出的系统在运行2 a或150 d后分别达到稳定状态,系统不再需要额外从公用电网购电,减轻了电网供电压力的同时,降低了运营商的购电成本。

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。

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。

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。

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。

Multi-stage Sensitivity Analysis of Distributed Energy Systems: A Variance-based Sobol Method

In the face of the pressing environmental issues,the past decade witnessed the booming development of the distributed energy systems(DESs).A notable problem of DESs is the inevitable uncertainty that may make DESs deviate significantly from the deterministically obtained expectations,in both aspects of optimal design and economic operation.It thus necessitates the sensitivity analysis to quantify the impacts of the massive parametric uncertainties.This paper aims to give a comprehensive quantification,and carries out a multi-stage sensitivity analysis on DESs from the perspectives of evaluation criteria,optimal design and economic operation.First,a mathematical model of a DES is developed to present the solutions to the three stages of the DES.Second,the Monte-Carlo simulation is carried out subject to the probabilistic distributions of the energy,technical and economic parameters.Based on the simulation results,the variance-based Sobol method is applied to calculate the individual importance,interactional importance and total importance of various parameters.The comparison of the multi-stage results shows that only a few parameters play critical roles while the uncertainty of most of the massive parameters has little impact on the system performance.In addition,the influence of parameter interactions in the optimal design stage are much stronger than that in the evaluation criteria and operation strategy stages.