基于多元GARCH-VaR的水电站短期发电风险调度

发电风险调度是电力市场下水电企业风险规避及管理的一种方式。基于VaR风险测量理论,在水电站短期优化调度中考虑电价风险,提出了更易理解、更具有可操作性的风险收入指标,并将GARCH-VaR电价风险测量模型与水电站短期优化调度模型有机耦合,建立了多元的GARCH-VaR发电风险调度模型。通过实例分析得到两种极端风险调度下的出力组合方案,同时还可以根据不同的风险水平和收入期望设置风险收入限额,得到同一风险下的最优组合解,为水电站参与市场竞争、短期发电风险管控提供了决策依据。     

基于分时电价的水库调度图优化研究

以芹山水库为例,结合分时电价原理与水库优化调度理论,划分了分时电价的时段,建立了考虑电价的以水电站水库发电效益最大为目标、兼顾保证出力要求的优化调度模型,应用改进的遗传算法优化水库常规调度图.结果表明,考虑分时电价影响后平均出力变小,能多发峰电,增加发电效益.     

含变频泵泵站动态规划优化模型的敏感性分析

泵站实际运行时的运行参数不一定能符合泵站最优数值,为研究模型实际运行的特征及相关参数的敏感性,基于已建立的含变频泵的泵站优化调度的能耗模型和日运行电费优化模型,采用全局敏感性分析Morris法,以瞬时流量、瞬时扬程及日调水量、日均扬程和峰谷最大最小流量为变量参数,改变其取值范围得到含变频泵的单级泵站对应敏感性参数下模型输出结果,并进行敏感性分析得到实际运行的特征。结果表明,能耗、电费、单位流量能耗和单位水量电费随瞬时流量、日调水量的增加而增加;能耗、电费随扬程的增加而增加,单位扬程能耗、单位扬程电费在设计扬程32.15m处最少,最节能,性价比最高;在不超过机组承受能力和满足各种运行条件的情况下,高峰时段能运行的最小流量越小,整个泵站日运行电费越低;低谷时段可运行的最大流量越大,整个泵站日运行电费越大。研究结果为全面了解泵站的实际运行特征及指导实际运行提供借鉴。     

基于电价影响的水电站装机容量选择

针对不同电价对水电站装机容量影响的决策问题，通过水力发电过程相关物理参数的数学建模，揭示了水电站投入产出关系曲线的凸性，利用经济学的边际分析原理，得出在利润最大化的原则下，水电站年化投资的边际单位电度成本等于电价时，水电站取得最优投资和最优装机容量，从而阐明了电价与水电站装机容量相互影响的内在规律，为选择水电站装机容量提供了技术经济理论依据。     

Cathode flow field design for nitric oxide/hydrogen fuel cell in cogeneration of hydroxylamine and electricity

A three‐dimensional model is developed for an NO/H₂ fuel cell cogenerating hydroxylamine and electricity. The model describes the distribution of velocity and concentration on the cathode side of the fuel cell, making the assumption of fuel excess on the anode side. The developed CFD‐based model is used for evaluation of various cathode flow field designs. Simulation results indicate the possibility of enhancing the fuel cell performance by decreasing the maldistribution of fields. A new cathode flow field design is developed for NO/H₂ fuel cell with an improved performance for both energy and hydroxylamine production. Copyright © 2016 John Wiley & Sons, Ltd.     

Extended sugarcane biomass utilisation for exportable electricity production in Mauritius

The availability and exportable electricity-production potential of bagasse and sugarcane residues are estimated for various technologies which determine steam production and utilisation at cogenerating sugar factories. Almost 565 kg of fibrous sugarcane biomass (expressed as kilogrammes of bagasse at 50% moisture) are potentially available for exportable electricity production for every tonne of cane milled. A “bagasse proper only” strategy would utilise 28% of the fibrous cane biomass and can potentially produce between 60 to 180 kW h of electricity per tonne of millable cane. Use of cane tops and leaves as a bagasse extender would utilise another 32% of the sugarcane biomass and the electricity output could range between 146 and 401 kW h/t of millable cane. The extreme case where 100% of the fibrous sugar cane biomass is utilised has the potential of producing up to 678 kW h/t of millable cane.     

Performance analysis of power generating sludge combustion plant and comparison against other sludge treatment technologies

Expectations on wastewater sludge treatment and recovery of its energy and material contents are increasing because of the tightening legislation and the obligation to reduce environmental impacts of sludge disposal. The objective of this study was to analyze the performance of a heat and power generating sludge combustion plant from technical and economical viewpoints and to compare the studied concept to optional sludge treatment technologies. The plant performance was modeled for sewage sludge produced by approximately 200,000 inhabitants. Two plant sizes below 1000 kWe range were investigated, the smaller plant using sludge as the only fuel and the larger plant with wood chips as the additional fuel. The plants were compared with heat-only plants of similar size. The payback periods for heat-only plants are typically shorter than with the cogenerating plants because the changes in plant investment affect stronger the economy than do the revenues from selling electricity. The gate fee of sludge treatment has the strongest effect on the payback period. The selection of the plant concept (cogeneration, heat only or pure electricity generation) is, however, affected more by the local demand of heat and electricity than pure economy. The selection of the optimal technology for sludge treatment is a complicated task. The studied concept can be the optimal choice, for example, if there is no cement kiln or co-combustion possibility near the source of sludge, if there is no land enhancement demand for the digested sludge, or if the energy surplus from combustion compared to anaerobic digestion is considered more valuable than nutrient recovery possibility from digestion. If the new technology concept is found competitive, it still has to meet the challenge of acceptability from the business, social and cultural points of view.     

基于市场偏差考核的梯级水电调度模型研究

偏差考核现已成为电力市场交易的常规环节,发电企业若不处理好相关问题、合理调度运行,将影响其市场收益,不利于企业的健康持续发展,进而对电力市场的健全发展造成一定影响。因此,为给企业合理应对偏差考核提供参考,首先对偏差电量考核规则进行概述,建立了计及偏差考核的电站收益模型,随后考虑梯级各电站间水力联系,基于单站运行约束条件,构建了基于偏差考核的梯级水电调度模型,并以四川省某流域梯级共8级电站为例,利用逐步优化算法进行计算。结果表明,梯级各站各考核时段电量偏差率介于-0.799%～0.558%之间,均免受偏差考核。     

喜河水电站施工进度优化设计与实践

由于汉江洪水峰高量大、陡涨陡落,喜河水电站施工规划充分结合宽河床、低水头、大泄量、分三期施工导流的特点,以尽量提前下闸蓄水、首台机组提前发电为基础,通过科学、合理的施工进度优化设计,使电站提前半年并网发电。     

班电量考核制度下龙首电站水库优化调度研究

水库优化调度是水能高效利用,提高电站经济效益的有效措施。如何增发电量促进经济效益最大化已成为龙首一、二级水电站亟待解决的问题。文中从管理体制方面入手,研究班电量考核制度下的水电站水库优化调度,结果表明班电量考核制度在拦蓄洪水、提高水情预报准确率、增发电量上有显著的作用,为提高水电站运行和综合管理水平提供依据,为以后水电站水库优化调度工作提供新思路新方法。     

基于青海地区在运光伏电站监测数据的容配比提升分析

随着光伏发电技术进步,近年来光伏组件价格呈快速下降趋势,于是对早期光伏电站进行大规模的光伏组件扩容翻新有了实质性的经济意义。根据青海地区正在运行的光伏电站的实时监测数据,建立光伏组件-逆变器限电率模型,以度电成本(LCOE)为考核指标,分析在不同扩容工程的工程造价影响下,光伏组件-逆变器容配比(下文简称“容配比”)与LCOE的敏感性关系,以确定在运光伏电站扩容后的最佳容配比,为未来光伏电站扩容设计提供指导方法。     

On the optimal planning of a hydrogen refuelling station participating in the electricity and balancing markets

This paper presents an optimisation model to assess the techno-economic feasibility of a hydrogen refuelling station, which purchases power from the electricity market, supplies the mobility sector with hydrogen, and participates in the ancillary service market. The problem is formed as a mixed-integer nonlinear programming model to investigate the optimal operational plans considering the nonlinear behaviour of an electrolyser and grid costs calculation model. Obtained results from various scenarios in 2020 and 2030 show that participation in the reserve market considering optimal sizing and dispatch of components increase revenues up to 16%, and as a result, decrease the hydrogen break-even price by up to 4.7% and 6.4% in 2020 and 2030, respectively. Exemption from tax and levies for connection to the grid reduces the hydrogen break-even price by up to 13%. Plant operators could benefit from the proposed approach to schedule components reliably while meeting the hydrogen demand and maximising the annual profits.     

Smart management of distinct plug‐in hybrid electric vehicle charging stations considering mobility pattern and site characteristics

Management of plug‐in hybrid electric vehicles (PHEVs) is an important alternative energy solution to accord the prevailing environmental depletion. However, adding PHEVs to the existing distribution network may stimulate issues such as increase in peak load, power loss, and voltage deviation. Addressing the aforementioned issues by incorporating distinct mobility patterns together will develop an attractive energy management. In this paper, suitable location of the charging station is presented for a novel 2‐area distribution system following distinct mobility patterns. A comprehensive study by considering the optimal, midst, and unfit site for placing the charging station is incorporated. For managing the charging sequence of PHEVs, a meta‐heuristic solving tool is developed. The main contribution of this programming model is its ability to schedule the vehicles simultaneously in both the areas. The efficiency of the proposed energy management framework is evaluated on the IEEE 33‐bus and IEEE 69‐bus distribution systems. The test system is subjected to different scenarios for demonstrating the superior performance of the proposed solving tool in satisfying the convenience of vehicle owner along with reducing the peak demand. The results show that charging at low electricity price period and discharging at high electricity price period enables the minimum operational cost.     

Optimal configuration for photovoltaic storage system capacity in 5G base station microgrids

Base station operators deploy a large number of distributed photovoltaics to solve the problems of high energy consumption and high electricity costs of 5G base stations. In this study, the idle space of the base station’s energy storage is used to stabilize the photovoltaic output, and a photovoltaic storage system microgrid of a 5G base station is constructed. Aiming at the capacity planning problem of photovoltaic storage systems, a two-layer optimal configuration method is proposed. The inner layer optimization considers the energy sharing among the base station microgrids, combines the communication characteristics of the 5G base station and the backup power demand of the energy storage battery, and determines an economic scheduling strategy for each photovoltaic storage system with the goal of minimizing the daily operation cost of the base station microgrid. The outer model aims to minimize the annual average comprehensive revenue of the 5G base station microgrid, while considering peak clipping and valley filling, to optimize the photovoltaic storage system capacity. The CPLEX solver and a genetic algorithm were used to solve the two-layer models. Considering the construction of the 5G base station in a certain area as an example, the results showed that the proposed model can not only reduce the cost of the 5G base station operators, but also reduce the peak load of the power grid and promote the local digestion of photovoltaic power.     

首都国际机场T3制冷站的运行方案研究

国内最大单体航站楼首都机场B航站楼采用区域供冷模式。文中针对，13制冷站的负荷特点和能耗特点进行经济性分析。首先结合峰谷分时电价与航空港负荷特点，利用冷水输送距离长、系统负荷延迟大、负荷与航班数目联系紧密等特性，对制冷站运行方式进行经济性优化；其次分析制冷站的能耗结构，分析不同冷冻水供水温度与制冷站总能耗的关系，发现存在一个最佳供水温度使系统总能耗达到最小。由于大型航空港的负荷特点相似，文中对大型航空港区域供冷系统经济运行具有一定的参考价值。     

计及购电成本的电网交易能力研究

在电力市场环境下,考虑购电成本对电网交易能力的影响,建立兼顾电网交易能力和购电成本的多目标交易优化模型,运用模糊建模的方法将多目标优化问题转化为求解最大满意度的单目标非线性规划问题,采用原对偶内点法求解。通过对IEEE-30节点测试系统进行仿真计算,结果表明所提出的多目标交易优化模型,可以在提高交易能力的同时尽量减小购电成本,验证了模型及算法的有效性。     

变尺度混沌蜂群算法在梯级库群优化调度中的应用

针对流域梯级水电站长期优化调度模型存在高维、非凸、非线性等特点,提出一种改进的变尺度混沌蜂群算法(VCBA),通过引入混沌方程和余弦收缩策略,使其具有更强的全局收敛能力和更快的收敛速度。以丰枯分时电价下金沙江下游梯级水电站群长期优化调度作为工程背景进行实例研究,并将计算结果与基本蜂群算法(BA)和粒子群算法(PSO)进行比较。结果表明,VCBA求解梯级水电站长期优化调度问题收敛速度快且优化结果精度较高,满足实际优化运行需求,具有很高的工程应用价值。     

A Mixed Integer Linear Programming model of a zonal electricity market with a dominant producer

We consider a liberalized electricity market, divided in zones interconnected by capacitated transmission links, where a large dimensional power producer operates. We introduce a model for determining the optimal bidding strategies of the large dimensional producer, so as to maximize his own market share, while guaranteeing an annual profit target and satisfying technical constraints. The model determines the optimal medium-term resource scheduling and yields the hourly zonal electricity prices, as it includes constraints representing the Market Clearing process. In order to compute the global solution, the complementarity conditions are formulated as mixed integer linear constraints and the revenue terms are expressed by piece-wise linear functions. The model can be used for analyzing the behavior of market prices in electricity markets where a large dimensional producer can exert market power. It can also be used by investors as a simulation tool for evaluating both the impact on the market and the profitability of investment decisions in the zonal electricity market. A case study related to the Italian electricity market is discussed.     

Robust design of off-grid solar-powered charging station for hydrogen and electric vehicles via robust optimization approach

In this article, a robust optimization approach for designing an off-grid solar-powered charging station is proposed to provide electric vehicles (EVs) with electricity and hydrogen vehicles (HV) with hydrogen. A water electrolyzer (WE) is installed in the system to produce and store hydrogen, which is used by the HVs and fuel cell (FC). During the inaccessibility of the photovoltaic (PV) system to feed the EVs, the FC runs on hydrogen to regenerate electricity. Besides, in case the PV system and FC have power shortage to meet the demand of EVs, a diesel generator contributes to electricity production. There are uncertainties involved in the power profile of the PV system as well as the hydrogen and electric demands of the charging station. The novelty of this paper is to integrate robust optimization as a powerful nonstochastic framework into the mixed-integer linear programming (MILP) of the deterministic model to deal with the uncertainties. The technical and economic results prove that the construction of the charging station by considering the highs level of robustness against the negative impacts of uncertainties leads to higher capacities of the PV system and diesel generator. Consequently, the total annualized cost increases from $ 287,256 in deterministic mode to $ 326,757 in robust mode, by 13.75%.     

Reliability evaluation and analysis for NEV charging station considering the impact of charging experience

Battery electric vehicles (BEVs) and hydrogen fuel cell vehicles (HFCVs) will predominate in near future, and the new energy vehicle (NEV) charging station which provides charging services for aforementioned NEVs could grow rapidly. The reliability of the NEV charging station would be the primary concern for early construction and NEV users. This study investigates the reliability evaluation of NEV charging station considering the impact of charging experience and analyzes the influence of various factors by comparing the evaluation results. The explicit modelling of the station considering power generation system, coupling devices and hydrogen storage is presented and an optimal revenue model is established to coordinate the operation of the station. A reliability index system is established to evaluate the charging reliability of the NEV charging station and reflect the charging experience. In addition, an amount model estimating the number of vehicles accessed in the coming days is proposed to address the impact of driver charging experience on the reliability evaluation. The results show that it is necessary to consider the charging experience in reliability evaluation. The comparison and analysis of reliability evaluation results reveal that the charging reliability and profit of the charging station are influenced by the initial hydrogen in tank, the price of hydrogen/electricity and the sizes of electrolyzer, hydrogen tank and fuel cell. The reliability evaluation provides guidance for determining the parameters of these factors.