日前和实时市场统一电能交易模型

分析了目前电力市场普遍存在的由日前市场和实时市场组成的2市场分开交易模式,指出针对这种2市场分开竞价的分开优化调度的设计机制并不是最经济的。针对负荷需求的随机性,提出协调考虑日前市场和实时市场的统一电能交易新构思,即仍沿袭2市场采用不同的结算电价(日前统一清除价和实时电价)的模式,统一建立2市场总的购电费用模型,通过优化日前电能交易量,达到总体购买费用最低。基于随机负荷需求,建立了2市场统一协调的电能交易模型(unifiedenergytradingmodel,UETM),论述了按照UETM交易的总购电费用不高于常规的2市场分开交易的结果,对UETM的求解算法进行了探讨,并用一简单算例说明了UETM能给出更经济的交易结果,最后对UETM的特点和适用范围进行了探讨。

基于ARDL算法的电力用能模型研究

立足电力消费视角,研究建立“电-能分析模型”,挖掘电与能的内在关联,引入宏观经济因素,通过灵活设计ARDL自回归分布滞后模型的使用方法,测算掌握各分行业的能源消费总体情况,助力政府部门评估行业的电气化水平。从各能源消费相关特征量历史变化情况角度出发,预测能源消费未来走势,为政府部门的能源消费宏观分析与战略规划、能源计量水平提升与监察实施等工作提供方法支撑。

基于时间序列的电能路由器能流预测模型

为解决以电能路由器为基本节点的能源互联网中的能流预测问题,分析了居民用电、大型商业用电、小型商业用电、光伏出力四类能流的主要影响因素,利用时间序列中的ARIMA模型构建了不同性质的能流预测模型,在此基础上综合考虑不同性质的能流和能源局域网的路由策略,进而构建了电能路由器能流预测模型。将该模型应用于New Hampshire Electric Co-op（NHEC）2013年3月的能流预测时,发现在路由策略下分布式电源充分条件下储能设备充裕时,对电能路由器能流EEF无影响;储能设备有限时,对EEF影响较大,EEF频繁波动;无储能设备时,对EEF影响较大,10：00~19：00时波动大;在分布式电源有限条件下,三种储能设备情况下,对电能路由器能流EEF均影响较大。

考虑实时市场平衡费用的含风电日前市场电能-备用联合出清模型

风电出力的不确定性为日前市场出清带来了挑战。提出一种风电参与的日前电能-备用联合出清模型,采用多场景技术描述风电出力的不确定性,基于场景集合求解模型达到出清结果。所提出的模型引入风电出力不确定性所带来的备用购买费用和实时市场的平衡费用来考虑日前市场出清结果对实时市场的影响,以达到减少实时市场的平衡压力,保障系统稳定运行的效果。同时该模型考虑弃风和失负荷惩罚费用来保障风电资源的充分利用和系统的安全稳定运行。改进的IEEE30系统算例结果对比及分析表明,所提出的模型可充分利用风电资源,有效降低日前市场电能生产成本,并减少弃风量,降低失负荷风险。在风电大规模接入电力系统的情况下具有较好的实际应用价值。

发动机生产基地电能消耗模型建立及降耗措施

电能消耗费用是大型企业生产成本的重要组成部分之一。通过对主要能耗设备、用能方式进行跟踪,结合生产方式、工作效率等影响因素,某发动机生产基地建立了电能消耗模型;并以电能消耗模型及实际数据为支撑,通过实施多项管理及工艺改进措施,实现了能耗降本。

基于物联网制造企业电能综合监控系统

能源监控是制造企业实施生产精益化与智能制造的重要内容。针对稀有金属加工制造企业生产与装备特点,研究基于物联网的企业电能综合监控系统,提出系统物联网架构和系统软件构成,采用电能计量表、智能网关与网络摄像机进行电能数据和状态信息采集,以太网、光纤环网组成传输网络;运用BP神经网络构建电能预测模型,设计ADO组件进行数据交换与处理。该系统实现了制造企业电能计量与统计分析、电能预测平衡监控、用电负荷与节能优化运行,提高企业电能有效利用和能源综合监控水平,具有典型的应用价值。

关口电能表远程在线校验方法及其技术实现

提出一种关口电能表远程在线校验方法,其具体实现,是在电能计量关口处增设一套高精度电压、电流前置采集装置,以更准确获取该处的电压、电流、电能脉冲、现场温度及湿度等数据信息,并将这些数据信息压缩后,上传至装设在主站的关口电能表在线运维管理系统,由该系统根据选定的电能计量算法算出电能量值,并与被校关口电能表计量的电能量值进行比较,进而估算出被校电能表的相对误差;同时,根据事先建立的故障模型,评估被校关口电能表的健康度情况,对可能存在问题的被校关口电能表发出告警信息,以确定最佳检定时机,从而建立起一种"当检即检"的关口电能表远程在线校验运维管理机制。

多适应电能交易模型设计及系统实现研究

我国电力市场与世界上其他国家或地区存在比较大的差异,不仅体现在价格形成机制上,还反映在要维护社会公平,促进节能减排,兼顾各利益调整。随着电力改革逐步深入,电能交易日益丰富,不同交易品种有不同软件支撑。为提高系统效率,对不同交易品种在业务上进行细分,分析关键技术上的异同,并基于此提出一套多适应电能交易模型和系统实施方案。实际算例表明,多适应电能交易模型简单、实用,能较好地兼顾市场机制和国家政策两方面的作用。

Power consumption in a field emission panel

The power consumption and electric field distribution in a field emission display （FED） panel is optimized with a novel pixel structure. A circuit model is proposed to estimate the total power consumption in an FED panel which is composed of anode energy consumption, energy loss due to the leakage current and the energy dissipated in the parasitic capacitances. Moreover, the parasitic capacitances play a vital part in the power consumption and driving performance. In order to lower the parasitic capacitances, multiple dielectric layers are used as the gate electrode. Due to different etching speeds, a novel pixel structure is formed. As a result, the power consumption of an FED panel is reduced by 28% in a full white picture, and the electron beam performance is also better than that of the conventional structure.

Calculation model of edge carbon atoms in graphite particles for anode of lithium-ion batteries

Based on the hexagonal crystallite model of graphite,the electrochemical characteristics of carbon atoms on the edge and basal plane were proposed by analyzing graphite crystal structure and bonds of carbon atoms in different sites.A spherical close-packed model for graphite particle was developed.The fractions of surface carbon atoms（SCA） and edge carbon atoms（ECA） were derived in the expression of crystallographic parameters and particle size,and the effects of ECA on the initial irreversible capacity and the mechanisms of action were analyzed and verified.The results show that the atoms on the edge are more active for electrochemical reactions,such as electrolyte decomposition and tendency to form stable bond with other atoms and groups.For the practical graphite particle,corresponding modifying factors were introduced to revise the difference in calculating results.The revised expression is suitable for the calculation of the fractions of SCA and ECA for carbon materials such as graphite,disordered carbon and modified graphite.

Insights into SO_2 and H_2O co-adsorption on Cu(100) surface with calculations of density functional theory

The co-adsorption behaviors of SO2 and H2 O on face-centered cubic Cu（100） ideal surface were studied using the GGA-r PBE method of density functional theory（DFT） with slab models. The optimized structures of single H2 O and SO2 on Cu（100） surface were calculated at the coverage of 0.25 ML（molecular layer） and 0.5 ML. The results show that there was no obvious chemical adsorption of them on Cu（100） surface. The adsorbed structures, adsorption energy and electronic properties including difference charge density, valence charge density, Bader charge analysis and partial density of states（PDOS） of co-adsorbed structures of H2 O and SO2 were investigated to illustrate the interaction between adsorbates and surface. H2 O and SO2 can adsorb on surface of Cu atoms chemically via molecule form at the coverage of 0.25 ML, while H2 O dissociated into OH adsorbed on surface and H bonded with SO2 which keeps away from surface at the coverage of 0.5 ML.

Structure and Properties of Hydrotalcite Using Electrostatic Potential Energy Model

The electrostatic potential energy model of hydrotalcites was based on the theory of crystallography. The anionic potential energy of MgAl-hydrotalcites, with 20 layers and 2107 anions per layer, was calculated, and the anionic stability of the hydrotalcites was investigated. The charge density of the layer and the distance between the adjacent anions varied with the molar ratio of Al^3＋/（Mg^2＋ ＋ Al^3＋）. Anionic potential energy depended on the charge and size of the anions. Calculation results remained consistent with thermal stability and the ion exchange ability reported. This model is able to predict anionic stability of the hydrotalcites.

Dynamic modelling and robust current control of wind-turbine driven DFIG during external AC voltage dip

Doubly-Fed Induction Generator （DFIG）, with vector control applied, is widely used in Variable-Speed Constant- Frequency （VSCF） wind energy generation system and shows good performance in maximum wind energy capture. But in two traditional vector control schemes, the equivalent stator magnetizing current is considered invariant in order to simplify the rotor current inner-loop controller. The two schemes can perform very well when the grid is in normal condition. However, when grid disturbance such as grid voltage dip or swell fault occurs, the control performance worsens, the rotor over current occurs and the Fault Ride-Through （FRT） capability of the DFIG wind energy generation system gets seriously deteriorated. An accurate DFIG model was used to deeply investigate the deficiency of the traditional vector control. The improved control schemes of two typical traditional vector control schemes used in DFIG were proposed, and simulation study of the proposed and traditional control schemes, with robust rotor current control using Internal Model Control （IMC） method, was carded out. The validity of the proposed modified schemes to control the rotor current and to improve the FRT capability of the DFIG wind energy generation system was proved by the comparison study.

Effect of Electron Itineracy on Magnetism of S=1／2 Ferromagnetic Ising Model

The effect of electron itineracy on the magnetism of S＝1/2 ferromagnetic Ising model is investigated by introducing a hopping term. The electron Green's function method is used to deal with this Hamiltonian. Here emphasis is made on that the magnetization is caused by the difference between the filling of spin-up and spin-down electrons.This concept is in accordance with that of band structure theory. In the zero band width limit, our results are the same as obtained by spin Green's function method. However, our method achieves more detailed physical information. The spontaneous magnetization, Curie temperature, total energy, and specific heat are calculated and investigated in detail by the densities of states. Hopping term depresses the Curie temperature but remains the order-disorder transformation still to be second order transition. Above the transition point, the energy band is the same as that of tight binding system because exchange interaction has no effect anymore. While under the transition point, the energy band splits into two subbands due to exchange interaction.

Improvement of chromium biosorption through protoplast electrofusion between Candida tropicalis and Candida lipolytica

Protoplasts from Candida tropicalis and Candida lipolytica were fused under an optimized electrofusion （electrical pulse strength 6 kV/cm, pulse duration time 40μs and pulse times 5） and then regenerated on YEPD media for achieving new genotypes with higher chromium loading capacity. A target fusant RHJ-004 was screened out by its chromium resistance and chromium-sorbing capacity tests for further research. The comparative study of applicability shows that the fusant has better performance than its parent strains in respect of solution pH, biomass concentration and chromium loading capacity. Especially for treating low concentration Cr（VI） （〈20 mg/L）, above 80% chromium is sequestered from the aqueous phase at pH 1-9. Atomic force microscopy （AFM） visualizes the distribution of chromium on the binding sites of the cells, suggesting that the altered surface structure and intracellular constitutes of the fusant associate with its increased biosorption capacity. The rapid biosorption processes of chromium foUow the Langmuir model well.

Design and Simulation of IEC 62056 Electricity Meter Model

This paper gives a brief introduction of IEC 62056 standards at first and then discusses the details about how to build the meter function model and the data model according to IEC 62056 standards.Finally it is described how to realize the IEC 62056 electricity meter by a simulation instance.

Analytical Solution for Model-Based Dynamic Power Factor Measurement in AC Resistance Spot Welding

On the basis of welding transformer circuit model, a new measuring method was proposed. This method measures the peak angle of the welding current, and then calculates the dynamic power factor in each half-wave. An artificial neural network is trained and used to generate simulation data for the analytical solution, i.e. a high-order binary polynomial, which can be easily adopted to calculate the power factor online. The tailored sensing and computing system ensures that the method possesses a real-time computational capacity and satisfying accuracy. A DSP-based resistance spot welding monitoring system was developed to perform ANN computation. The experimental results suggest that this measuring method is feasible.

Theoretical understanding of electrocatalysis beyond thermodynamic analysis

As the green and sustainable development of human society highly relies on renewable energy,it has been recognized that electrocatalysis is a key technology to this end.High efficient ways of carbon-neutralization(eCO_(2)RR),reverse artificial nitrogen cycle(RANC),and oxygen chemistry(OER and ORR)all can be driven by electrocatalysis.Advanced theoretical study is an important means to fundamentally understanding electrocatalytic reactions.Herein,we review a few significant issues in theoretical electrocatalysis.First,electrochemical barriers and potential effects are essential for a more accurate description of reaction mechanism and activity.Meanwhile,consideration of competitive reaction path is also one of the important aspects,as novel insights and anomalous volcano trend can be obtained.Finally,a microenvironment exerted by confined space can tune the capacitance of electrochemical interface and(electro)chemical potential of proton,resulting in a possibility to improve reaction activity,which opens a new avenue for design of catalyst.

Modeling and control of a small solar fuel cell hybrid energy system

This paper describes a solar photovoltaic fuel cell (PVEC) hybrid generation system consisting of a photovoltaic (PV) generator, a proton exchange membrane fuel cell (PEMFC), an electrolyser, a supercapacitor, a storage gas tank and power conditioning unit (PCU). The load is supplied from the PV generator with a fuel cell working in parallel. Excess PV energy when available is converted to hydrogen using an electrolyser for later use in the fuel cell. The individual mathematical model for each component is presented. Control strategy for the system is described. MATLAB/Simulink is used for the simulation of this highly nonlinear hybrid energy system. The simulation results are shown in the paper.

Study on switched reluctance generator

The linear and non-linear math models of the switched reluctance generator (SRG) in generator mode were established in this work. The phase current and energy conversion process during generator operation were simulated by the linear math model. The non-linear math model was used to analyze the characteristics of the SRG operation in self-excitation mode and in separately-excitation mode. Some important findings on how the SRG is operated and controlled were obtained in this study, which provides theoretical basis for further design and experimental study.