Optimal SOC Headroom of Pump Storage Hydropower for Maximizing Joint Revenue from Day-ahead and Real-time Markets Under Regional Transmission Organization Dispatch

In response to the increasing penetration of volatile and uncertain renewable energy,the regional transmission organizations(RTOs)have been recently focusing on enhancing the models of pump storage hydropower(PSH)plants,which are one of the key flexibility assets in the day-ahead(DA)and real-time(RT)markets,to further boost their flexibility provision potentials.Inspired by the recent research works that explored the potential benefits of excluding PSHs’cost-related terms from the objective functions of the DA market clearing model,this paper completes a rolling RT market scheme that is compatible with the DA market.Then,with the vision that PSHs could be permitted to submit state-of-charge(SOC)headrooms in the DA market and to release them in the RT market,this paper uncovers that PSHs could increase the total revenues from the two markets by optimizing their SOC headrooms,assisted by the proposed tri-level optimal SOC headroom model.Specifically,in the proposed tri-level model,the middle and lower levels respectively mimic the DA and RT scheduling processes of PSHs,and the upper level determines the optimal headrooms to be submitted to the RTO for maximizing the total revenue from the two markets.Numerical case studies quantify the profitability of the optimal SOC headroom submissions as well as the associated financial risks.

Earth’s Serious Anisotropy, Non-Inertiality, Ether, Gain of Free Energy, Revealed, Part 2

The present paper is of historic importance as well as the second part of [1]. In this second part, we detect important details about the orbit of the Earth and about the velocity (of magnitude 217 km/s) of the solar system around the center of the Milky Way galaxy. Some of these details concern the perihelion and aphelion of the orbit of the Earth. For several years we have observed that the return pulses, on the oscilloscope screen, appear to be more energetic than the initial pulses (See Part 1, Figure 2, for which the blue return pulse crests are much higher than the yellow initial crests). The used oscilloscope is and only must be, a storage oscilloscope, in other words, a computerized oscilloscope with a digital memory. The first oscilloscopes like this, came out, only after 1995, a relatively recent time that all wire velocity experiments and measurements were already completely investigated by science. We do astronomy, without receiving images by an astronomical telescope, but instead by sending signals around a loop and making an analysis using the same oscilloscope as in Part 1. We recommend to the reader to study Part 1 as a prerequisite. The Earth surface is accelerating with a centripetal acceleration, due to its rotation, thus it is not an inertial frame. Also, the Earth is evidently anisotropic, due to the same rotation, a second reason for it being a non-inertial rotating frame.

计及共享储能与光伏的园区多用户综合收益优化

针对含共享储能与户用光伏的园区场景,文中提出一种用户侧综合收益双层优化方法,充分挖掘共享储能灵活性及用户用电需求差异性,在实现用户整体经济效益最优的同时提升光伏消纳能力。模型上层为月前优化阶段,以用户月度用电成本最低为目标,考虑系统能量平衡、储能充放电约束以及储能荷电状态约束,优化工业用户最大用电功率,降低需量电费;模型下层为日前优化阶段,综合考虑用户综合收益及光伏消纳能力,以上层优化结果为约束条件,兼顾功率、储能等约束,提出共享储能充放电功率及用户与电网交互功率等日前优化策略,在用户月度整体经济性最优的前提下,实现用户侧每日经济效益的优化。最后,以南方某实际园区作为算例验证了文中所提方法的有效性。

基于保险精算理论的储能运营商利益分配策略

储能运营商可提高电力供应的可靠性,减少停电损失。为进一步扩大储能供电可靠性的应用场景并增加储能运营商的收益,提出一种基于保险精算理论的利益分配策略。先基于拟合停电损失分布,结合信度理论与纯保费模型,构建Bűhlmann保费模型;再建立基于健康指数的修正故障率模型,并采用最小路径法,计算各类用户的停电保险赔付概率;最后,将停电保险与峰谷套利相结合,构建储能运营商的收益模型,最大化其在全寿命周期内的收益,并将该收益与其未参加停电保险的收益进行比较。研究结果表明:与保险公司合作可大幅提高储能运营商的收益,加快投资成本回收。

交直流配电系统储能优化配置方法

为提高配电网对可再生能源的消纳能力并减轻可再生能源并网对配电网造成的影响,针对交直流混合配电系统,提出了一种考虑电压源型换流器和储能系统协调运行的储能容量双层优化模型,结合遗传算法与二阶锥规划方法对大规模非线性规划问题进行求解。最后,通过设置3种不同场景以验证模型的合理性和有效性。算例结果表明:储能系统和交直流混合配电系统协调运行能够有效抑制电压波动,提高储能系统的收益。

电力现货市场下山东电化学储能电站净收益分析

总结山东电力现货市场下电化学储能电站的相关政策。通过分析储能电站的各项收益、费用,得出电化学储能电站净收益的计算公式。通过分析电站净收益与上网电量、度电价差、综合效率、采用“两充两放”运行策略的关系,研究典型工况下临界点度电价差。通过山东某在运100 MW/200 MW·h电化学储能电站案例分析验证了净收益计算公式的有效性。研究结果可以为优化电站运行策略、提高电站收益水平提供参考。

风电-光伏-抽蓄-电制氢多主体能源系统增益的合作博弈分配策略

根据清洁能源示范基地的建设需求,提出基于合作博弈论的风电-光伏-抽蓄-电制氢多主体能源系统联合优化运行的增益分配策略.为兼顾系统运行安全性,构建上网出力互补性评价指标.风电、光伏、抽蓄、电制氢利益主体通过内部电量交易进行合作,以系统运行收益最大为优化目标构建联合优化调度模型.根据调度结果,应用合作博弈论中的最大最小成本法分配系统合作增量收益.利用风电-光伏-抽蓄-电制氢清洁能源示范基地12利益主体系统算例进行仿真验证,结果表明联合优化运行可实现各利益主体自身收益正增长,抽蓄库容、上网电价以及运行安全性需求会影响系统的合作增量收益.

考虑容量共享的新能源-电网-用户侧储能优化配置策略

在新能源场站、电网和用户侧配置储能有助于新型电力系统的安全经济运行,目前大多针对某侧储能需求独立考虑配置方案。忽略各侧储能的相互支援能力与共享空间,易造成社会储能资源浪费和储能投资回报率降低。为此,该文基于新能源场站、电网和用户侧独立储能的收益模式分析,讨论各侧储能的容量共享能力,并提出新能源-电网-用户侧储能的容量共享机制。进一步提出考虑容量共享的新能源-电网-用户侧储能配置双层优化模型,上层为长周期储能优化配置模型,下层为计及容量共享的短周期储能优化调度模型。建立计及容量共享的三侧储能配置方案优化求解方法。通过算例验证表明,该文所提方法可以实现系统各侧储能的共享、协同配置,从而有效提高各侧储能的容量利用率,避免系统中储能的冗余配置。

分散式储能与共享储能调峰效果和盈利模式对比分析

针对新能源+储能分散场站独立调度和共享储能统一调度2种运营模式,开展了技术调峰效果和收益模式对比分析。首先,建立多地块风/光+储能等7种应用场景模型,综合考虑新能源发电量、弃电率及储能利用率等指标因素,采用全年日电量平衡为基础的8760 h生产模拟仿真算法,对2种储能运营模式运行效果进行比较。其次,针对当前储能电价政策及储能盈利模式,建立储能收益模型,开展储能收益模式对比评价。分析结果表明,共享储能统一调度方式可充分利用风光发电时空互济性,提高新能源利用率,提升电力系统灵活性,且通过参加辅助服务及电力现货交易等拓宽收益路径,实现储能降本增效,共享储能在调峰效果和收益方面均优于分散场站独立调度运营模式。

Model Predictive Control Strategy for Residential Battery Energy Storage System in Volatile Electricity Market with Uncertain Daily Cycling Load

This paper presents a control strategy for residential battery energy storage systems,which is aware of volatile electricity markets and uncertain daily cycling loads.The economic benefits of energy trading for prosumers are achieved through a novel modification of a conventional model predictive control(MPC).The proposed control strategy guarantees an optimal global solution for the applied control action.A new cost function is introduced to model the effects of volatility on customer benefits more effectively.Specifically,the newly presented cost function models a probabilistic relation between the power exchanged with the grid,the net load,and the electricity market.The probabilistic calculation of the cost function shows the dependence on the mathematical expectation of market price and net load.Computational techniques for calculating this value are presented.The proposed strategy differs from the stochastic and robust MPC in that the cost is calculated across the market price and net load variations rather than across model constraints and parameter variations.

Control Design and Implementation of a Spiral Spring Energy Storage System Connected to a Grid via PMSG

For an innovative spiral spring energy storage system,the permanent magnet synchronous generator(PMSG)is utilized as the energy conversion device due to its simple structure,low weight and high torque.During power generation,the output torque and moment of inertia of the spiral spring are changing continuously and simultaneously and the parameters of the PMSG show uncertainties.Furthermore,the DC link voltage of the converter should be stable and the power injected into the grid needs to be controlled.First,the change features of the external power source and the uncertainties of the generator’s internal parameters are expressed as the comprehensive disturbances,which are introduced into the dynamic model of the PMSG and also modify the dynamic model.Then,the high gain observers are utilized to estimate the comprehensive disturbances,and an improved robust backstepping control scheme integrating L2 gain and high gain observers is proposed.Secondly,the gridside inverter controller for the DC voltage loop and reactive power loop is designed based on the backstepping theory.Finally,hardware implementation is fulfilled to verify the presented algorithm.The results show that high gain observers are able to accurately estimate the external and internal interferences;the proposed control scheme can effectively suppress the external and internal interferences and guarantees output current,operating speed of the PMSG and output reactive power to correctly track respective references,and effectively stabilize the DC link voltage.

海岛低碳综合能源微网优化方案设计

海岛微网不同季节的风光出力和负荷水平不同并且缺少跨季节性的长期储能方式,导致了当前海岛微网大规模弃风弃光和高额碳排放。为了提高风光利用率和降低碳排放,建立了包含氢储能系统和海水源热泵的海岛综合能源微网。以最小化年化成本、最小化弃风光率、最小化碳排放量为目标函数,以分布式电源出力和功率平衡为约束,采用NSGA-Ⅲ算法对各分布式电源的容量进行多目标优化配置,使用模糊隶属度函数选取综合满意度最大的解,算例结果证明了综合能源微网的优越性,为今后海岛微网的规划建设提供参考。

一种交错并联分裂开关电容升压变换器

该文提出了一种可用于光伏储能系统的交错并联分裂开关电容升压(Boost)变换器。其输入、输出电流均连续,且具有2种典型的控制方式:对称控制(d_(1)=d_(2))和均流控制(d_(2)=1/(2-d_(1)))。d_(1)、d_(2)分别为2个开关管的占空比。对称控制下,电压增益为传统Boost的(1+d_(1))倍,所有功率管的电压应力均等于输入电压U_(in)与输出电压U_(o)和的一半。均流控制且电流连续模式下,无需检测输入电流,即可在全占空比范围内实现两相电感的均流控制,且电压增益为G=2/(1-d_(1)),一个开关管和一个二极管的电压应力等于U_(o)/2,其余功率管的电压应力为U_(in)+U_(o)/2。该文详细分析了所提变换器在电流连续模式下的工作原理和2种控制方式下的稳态特性,并通过一台500W/50kHz的样机实验验证了理论分析的正确性。

基于光伏储能的DVR分数阶PI控制策略

动态电压恢复器(dynamic voltage restorer,DVR)是设备侧有效治理电压暂降故障的装置,目前DVR的控制设计基本采用比例积分(proportional-integral,PI)控制器,但是DVR为非线性系统,传统PI控制器并不能达到理想的控制效果。为改善DVR的控制效果,提出一种新型电压电流双闭环分数阶PI(fractional order PI,FOPI)控制策略。首先,以光伏储能系统为DVR直流侧能量源,并建立相应的三相逆变器前馈解耦数学模型;其次,设计光伏储能系统与逆变器的双闭环PI控制策略,并进行参数整定;之后,将整数阶控制策略推广到分数阶来改善控制效果,并采用增益变化时的鲁棒性准则对FOPI控制器进行参数校正;最后,搭建不同控制策略下的DVR仿真模型,仿真结果验证了FOPI控制器应用于DVR系统的可行性,且相对于传统PI控制器其具备更好的动态响应速度与抗干扰性能。

Battery Storage Configuration of AC/DC Hybrid Distribution Networks

The upscaling requirements of energy transition highlight the urgent need for ramping up renewables and boosting system efficiencies.However,the stochastic nature of excessive renewable energy resources has challenged stable and efficient operation of the power system.Battery energy storage systems(BESSs)have been identified as critical to mitigate random fluctuations,unnecessary green energy curtailment and load shedding with rapid response and flexible connection.On the other hand,an AC/DC hybrid distribution system can offer merged benefits in both AC and DC subsystems without additional losses during AC/DC power conversion.Therefore,configuring BESSs on an AC/DC distribution system is wellpositioned to meet challenges brought by carbon reductions in an efficient way.A bi-level optimization model of BESS capacity allocation for AC/DC hybrid distribution systems,considering the flexibility of voltage source converters(VSCs)and power conversion systems(PCSs),has been established in this paper to address the techno-economic issues that hindered wide implementation.The large-scale nonlinear programming problem has been solved utilizing a genetic algorithm combined with second-order cone programming.Rationality and effectiveness of the model have been verified by setting different scenarios through case studies.Simulation results have demonstrated the coordinated operation of BESS and AC/DC hybrid systems can effectively suppress voltage fluctuations and improve the cost-benefit of BESSs from a life cycle angle.

基于新型电力系统的电网储能控制方法研究

目前电网储能控制方法忽略了对电网储能系统中有功功率和无功功率耦合情况的考虑,有功网损、有功网损率、新能源损耗功率以及新能源损耗率均较高。提出基于新型电力系统的电网储能控制方法。通过改进的下垂控制方法对SOC均衡控制,输出电网储能系统的优化电压参考值,完成对电网储能系统的控制。实验结果证明:所提方法能够有效地提高电压处于允许范围的概率,并降低有功网损、有功网损率、新能源损耗功率和新能源损耗率,提出的储能控制方法能够适应新型电力系统,满足电力系统新要求。

电化学储能电站财务评价参数及盈利能力分析

选取近年来四个典型电化学储能电站投资数据,按建设工程总投资划分,分析电化学储能项目总投资构成及各分项费用占比情况;梳理组成储能电站生产运营总成本费用,确定了主要成本的取值标准;剖析储能电站收益来源,并构建储能电站放电收益计算模型。在此基础上进行典型储能项目盈利能力分析,得出主要指标平均值,并对建设投资、放电量、放电电价进行敏感性分析,明确了各盈利能力指标与敏感性因素变化的波动关系,研究结果有助于储能电站明确生产经营重点内容,从而提高电站经济效益。

抽水蓄能机组调频控制优化策略研究

随着越来越多的新能源并网接入,研究交流励磁抽水蓄能机组的调频控制策略,充分发挥其快速功率调节能力,有利于维持电网的安全稳定运行。为此,针对传统综合惯性控制中下垂环和惯性环增益参数,对交流励磁抽水蓄能机组参与电力系统频率调节特性的影响进行分析,提出了变增益系数惯性环和下垂环分时参与调节的综合调频控制优化策略,并对其控制参数进行整定;建立了三机电力系统的仿真模型,将所提出综合调频控制优化策略与传统综合惯性控制策略进行仿真对比分析,充分验证了所提策略的有效性。

储能经济性研究进展

储能在常规电力系统、可再生能源发电、分布式发电与微网、辅助服务等领域具有不同的作用和价值,其收益模式和经济评价方法也不同。但国内外对储能技术经济研究尚属于初期阶段,未形成成熟的经济评价体系。本文综述了国内外储能经济性的研究现状,结合不同储能技术在电力系统中的应用,分析了储能在不同应用领域的价值收益模式,初步建立了储能在不同收益模式下的收益模型。同时,分析了目前储能经济性研究的几种主流方法及其优缺点,以及储能经济性研究的发展趋势。

大口径方光束片状放大器小信号增益实验研究

介绍了一台 2 4 cm× 2 4 cm的大口径钕玻璃片状放大器 ,并且在不同充电电压下进行了实验测试。在充电电压为 2 2 k V、泵浦能密度为 1 4 .62 J/cm3的条件下 ,获得了 4 .9% cm-1的小信号增益系数和 2 .4 3 %的储能效率。