低压配网中继电保护的探讨

本文是作者结合相关工作实际,对低压配网中继电保护进行的具体论述.电力系统中,各种类型、大量的电气设备通过电气线路紧密地联结在一起.由于其覆盖的范围大、运行环境极其复杂以及各种人为因素的影响,电气故障的发生是不可避免的.在10kV低压配网系统中,上、下级继电保护之间的配合条件必须考虑周全,若考虑不周或选配不当,则会造成保护的非选择性动作,使断路器越级跳闸.     

独立风光互补发电系统的经济性分析

提出了一种较全面的独立风光互补发电系统的结构,分析了独立风光互补发电系统经济性指标,提出了分析该系统的经济性模型,并用该模型对一个具体的独立风光互补发电系统进行了分析,为独立风光互补发电系统的经济研究提供了参考。     

浅谈电力配网的运行管理

随着社会的发展和电力运用的范围越来越广泛,供电企业的任务不仅仅是提供电能这么简单,还要兼具保障电力配网运行的可靠性、安全性、加强电力配网的运行管理等能力,这样就能够极大的避免变电安全事故的发生。因为在整个供电系统中,电力配网的运行管理直接关系到整个电力配网的安全和稳定。本文就电力配网的运行管理进行全方位剖析,将电网运行管理中最为重要的运行可靠性、稳定性等进行问题发现和改进,以期能够为供电企业的发展提供参     

综合收益最优的贷款组合鲁棒优化模型

商业银行信贷经营的基本目标是资金来源与运用在效益性、安全性和流动性上的“三性”平衡,而贷款组合优化配置是商业银行维持或达到资金“三性”平衡的有效方式,也是商业银行信贷经营管理中的重要内容.而贷款的预期收益具有不确定性,如果简单地假设其预期收益率往往会出现与实际脱节的情况,因此需要考虑贷款期间可能出现的变化.针对这一特征,考虑构建风险调整后资本收益率(RAROC)最优的贷款组合鲁棒优化模型.根据某商业银行实际经营数据进行数值分析,结果表明该模型具有鲁棒性,不仅能够兼顾贷款组合综合收益以及未来收益的不确定性因素,同时还可以在贷款组合风险约束范围内获得最大收益,为商业银行贷款优化配置管理提供有效可行的决策依据.     

裂纹智能框架的三维有限元动力谐响应研究

采用三维有限元技术给出了面向框架结构健康监测应用的压电阻抗模型。分析中考虑压电片与主体结构之间界面特性的影响,将压电片-黏结层-主体结构作为整体耦合结构系统加以考察。与其它研究结果的对比研究验证了该有限元电阻抗模型的有效性和精确性。此外,还考察了各物理参数包括黏结剂材料性质对电阻抗信号的影响,尤其是框架中裂纹的深度和位置对电阻抗谱的作用。计算结果表明该压电阻抗模型能用于结构损伤识别。     

计及外部性的储能系统价值测算及经济性评估

以应用在电力系统中的电储能系统为研究对象,以外部性理论为基础,构建了计及外部性的储能系统经济性测算模型,并以储能系统接入光伏电站为例,采用贴现现金流分析方法,预估储能投资成本和收益,分别从投资者角度和社会整体效益角度,来研究储能系统应用在可再生能源发电侧的经济性,并进行了盈亏平衡分析。通过盈亏平衡曲线分析了储能盈亏平衡情景,经济性分析结果显示储能系统的外部性收益占年收益比例较大。     

基于鲁棒优化的煤电能源供应链中长期风险减轻策略

旨在为煤电能源供应链风险管理提供一个以价值型绩效为基础的整体框架,以形成中长期风险降低策略。首先对供应链不确定性、供应链风险和鲁棒优化进行了全面分析,界定了供应链节点企业,指出实际管理中的"下行风险"是煤电能源供应链风险管理的重点。然后,以为基于价值的管理提供实用的决策支持为建模思路,建立了基于鲁棒优化的煤电能源供应链风险管理模型,并对基本模型、对等模型和决策模型进行了详细阐述。最后,通过算例和科学的量化指标,从方案鲁棒性、目标鲁棒性和信息鲁棒性3个方面讨论了模型的有效性。     

一个抽水蓄能电站的优化论证模型

1、引言随着社会经济的发展 ,对电力供应的质量的要求日益提高 ,我国各大电力系统都面临着系统峰谷差不断扩大、调峰容量短缺的问题 ,建设抽水蓄能电站以解决电力系统的调峰电源问题被提到了议事日程。为论证抽水蓄能电站及系统调峰电源容量优化这一问题的需要 ,我们开发出了一个适用于包含水火电及抽水蓄能电站的混合电力系统中长期电源规划模型 ,该模型同时考虑了包括调峰电源容量优化在内的系统容量扩展优化和系统运行优化 ,以及一次能源平衡和环境约束 ,并较好的解决了模型的线性化及火电站煤耗曲线的非线性计算问题 ,提高了对系统运行…     

京津冀区域创新生态系统：运行机理及效果评价

通过构建“承载-集聚-行动-产出-辐射”5个子系统和“利润回馈-技术溢出-保障机制”3个循环动力机制的区域创新生态系统，建立指标体系并运用复合系统协同度和耦合协调度模型评价京津冀创新生态系统运行水平。结果显示：2008—2018年系统运行处于低水平协同阶段，子系统有序度逐年提高，系统间耦合能力经历由低度协调向中度协调的蜕变。三地创新的马太效应、产业链与创新链耦合不足、系统间联动机制不完善是制约系统协调的短板。最后，从构建要素平衡型流动机制、强化创新链-产业链融合、优化创新生态等方面提出相应建议。     

基于鲁棒优化方法的供应链协同创新——非完全竞争市场下的RSFC问题

供应链协同问题是企业供应链管理领域的一个热门话题。本文通过对传统零售商一供应商柔性~（RSFC）问题进行改进和延伸,将条件置于非完全竞争市场,从零售商视角探讨了非完全竞争市场下“零售商一供应商”两级系统最优订购策略问题,在利润最大化原则下建立起了运筹学模型,采用鲁棒优化方法进行模型求解,比较了不同形式不确定性水平下的优化结果差异。     

出力不确定下基于保险机制的风电供应链 最优交易决策

随着新一轮电力体制改革的日益推进,参与电力市场竞争是消纳风电等可再生能源的必经之路。由于风电出力受风速等自然条件影响,出力具有较强不确定性,导致其实际出力难以预测,使得风电商参与电力市场面临巨大的收益风险。合理地转移风电商的市场风险,引入有效的风险规避机制,对提高风电商收益稳定性具有重要意义。因此本文基于电量损失保险机制,建立了风电商、售电公司以及保险公司的Stackelberg博弈模型,通过逆向递归法求解纳什均衡,分析保险费率与市场三方利润之间的关系,得出市场主体风电商、售电公司以及保险公司的最优交易决策。最后通过具体算例分析验证得出,引入电量保险机制,制定适当的保险费率,能够使风电商、售电公司以及保险公司三方利益实现共赢。     

Locational-based coupling of electricity markets: benefits from coordinating unit commitment and balancing markets

We estimate the benefits of electricity locational marginal pricing (LMP) that arise from better coordination of day-ahead commitment decisions and real-time balancing markets in adjacent power markets when there is significant uncertainty in demand and wind forecasts. To do so, we formulate a series of stochastic models for committing and then dispatching electric generators subject to transmission limits. In the unit commitment stage, the models optimise day-ahead generation schedules under either the full set of network constraints or a simplified net transfer capacity (NTC) constraint, where the latter represents the present approach for limiting forward electricity trade in Europe. A subsequent redispatch model then creates feasible real-time schedules. Benefits of LMP arise from decreases in expected start-up and variable generation costs resulting from consistent consideration of the full set of network constraints both day-ahead and in real time. Meanwhile, coordinating adjacent balancing markets provides benefits because intermarket flows can be adjusted in real-time in response to changing conditions. To quantify these benefits, we analyse a stylised four-node network, examining the effects of varying system characteristics on the magnitude of the locational-based unit commitment benefits and the benefits of intermarket balancing. We conclude that both categories of benefits are situation dependent, such that small parameter changes can lead to large changes in expected benefits. Although both can amount to a significant percentage of operating costs, we find that the benefits of coordinating balancing markets generally exceed unit commitment benefits.     

Are Municipal Electricity Distribution Utilities Natural Monopolies?

The purpose of this study is to analyse the cost structure of the Swiss electricity distribution utilities in order to assess economies of scale and density and the desirability of competition in the distribution of electric power. A translog cost function was estimated using panel data for a sample of 39 municipal utilities over the period 1988–1991. The results indicate the existence of economies of density for most output levels and the existence of economies of scale only for small and medium-sized electric utilities. The empirical evidence suggests that franchised monopolies, rather than side-by-side competition, is the most efficient form of production organization in the electric power distribution industry. Further, the majority of the utilities analysed do not operate at an optimal service territory size. Therefore, the consolidation of small utilities whose service territories are adjacent is likely to reduce costs.     

Fuel inventory and price relationships in the U.S. electric power sector under regulatory and market change

Long-run relationships among coal inventories at U.S. electric power plants, corporate bond rates and coal, natural gas, and electricity prices are estimated over the period July 1976 to October 2014. Tests for constancy of the long-run relationships show periods of instability which coincide with major regulatory events in the electric power sector. Deregulation of the natural gas and electricity markets are likely sources of instability for the period mid-1994 to mid-2001. Additionally, inventory behavior may have had a smoothing effect over instability caused by natural gas prices during the recent U.S. shale boom. Policy makers should be aware that altering the regulatory environment can result in considerable fluctuations in how firms’ inventory decisions interact with input and output markets and opportunity costs in the long run.     

区域配电网全寿命周期成本优化研究

为了有效控制配电网运营成本和提高效益,针对新一轮电力体制改革的深入改革,区域配电网全寿命周期成本优化已成为一个重要研究方向。本文首先借助系统动力学模型分析了配电网复杂成本构成和筛选了影响成本的关键因子,并采用了改进蒙特卡法对关键影响因子进行混合抽样,得出配电网各关键因子对区域配电网全寿命周期成本影响的综合灵敏度系数；其次,建立了以关键影响因子对配电网全寿命周期成本总影响量最小为目标的成本优化模型,以及提出了GAACS组合算法对模型进行求解；最后,选取了某省的10kV配电网区域进行了实例分析,结果可得,经济条件对配电网成本影响最大,以及技术条件差的区域降低成本能力较大。。     

Evaluating wind-following and ecosystem services for hydroelectric dams in PJM

Hydropower can provide inexpensive, flexible fill-in power to compensate for intermittent renewable generation. Policies for hydropower dams maintain multiple services beyond electric generation, including environmental protection, flood control and recreation. We model the decision of a hydroelectric generator to shift some of its power production capacity away from the day-ahead energy market into a “wind-following” service to smooth the intermittent production of wind turbines. Offering such a service imposes both private and social opportunity costs. Since fluctuations in wind energy output are not perfectly correlated with day-ahead energy prices, a wind-following service will necessarily affect generator revenues. Seasonal wind patterns produce conflicts with the goal of managing rivers for “ecosystem services”—the maintenance or enhancement of downstream ecosystems. We illustrate our decision model using the Kerr Dam in PJM’s territory in North Carolina. We simulate the operation of Kerr Dam over a three-year period that features hydrologic variability from normal water years to extreme drought conditions. We use an optimization framework to estimate reservation prices for Kerr Dam offering wind-following services in the PJM market. Wind-following may be profitable for Kerr Dam at low capacity levels during some time periods if ecosystems services are neglected and if side payments, or reserves-type payments, are provided. Wind-following with ecosystem services yields revenue losses that typically cannot be recovered with reserves market payments. Water release patterns are inconsistent with ecosystem-services goals when Kerr Dam dedicates significant capacity to wind-following, particularly in drought years.     

The impact of carbon cap and trade regulation on congested electricity market equilibrium

Greenhouse gas regulation aimed at limiting the carbon emissions from the electric power industry will affect system operations and market outcomes. The impact and the efficacy of the regulatory policy depend on interactions of demand elasticity, transmission network, market structure, and strategic behavior of generators. This paper develops an equilibrium model of an oligopoly electricity market in conjunction with a cap-and-trade policy to study such interactions. We study their potential impacts on market and environmental outcomes which are demonstrated through a small network test case and a reduced WECC 225-bus model with a detailed representation of the California market. The results show that market structure and congestion can have a significant impact on the market performance and the environmental outcomes of the regulation while the interactions of such factors can lead to unintended consequences.     

SOCIAL COSTS OF ELECTRICITY GENERATION: WIND AND PHOTOVOLTAIC VERSUS FOSSIL AND NUCLEAR

This paper presents the results of research on the total costs to society of different technologies for electric power production in the Federal Republic of Germany. The analysis views electricity costs from a macroeconomic perspective and includes the internal or private costs as well as the social costs. The focus is on fossil and nuclear fuels as conventional energy sources on the one side and on wind and photovoltaic electricity as examples of renewable energy sources on the other.     

Energy distribution and economic growth

This research examines the physical constraints on the growth process. In order to run, maintain and build capital energy is required to be distributed to geographically dispersed sites where investments are deemed profitable. We capture this aspect of physical reality by a network theory of electricity distribution. The model leads to a supply relation according to which feasible electricity consumption per capita rises with the size of the economy, as measured by capital per capita. Specifically, the relation is a simple power law with an exponent assigned to capital that is bounded between 1/2 and 3/4, depending on the efficiency of the network. Together with an energy conservation equation, capturing instantaneous aggregate demand for electricity, we are able to provide a metabolic-energetic founded law of motion for capital per capita that is mathematically isomorphic to the one emanating from the Solow growth model. Using data for the 50 US states 1960–2000, we examine the determination of growth in electricity consumption per capita and test the model structurally. The model fits the data well. The exponent in the power law connecting capital and electricity is 2/3.     

中国新能源制氢潜力评价研究——基于31省份2017年和2030年的分析

使用SBM-Undesirable模型测算我国31省份的新能源制氢效率,从新能源制氢效率和新能源装机容量两个维度构建评价体系,再应用熵权评价法,对我国31省份的新能源制氢潜力进行分析,同时研究了新能源制氢潜力2017—2030年的变化情况。结果表明:风电制氢的效率明显高于光伏制氢;西北和华北地区的新能源制氢潜力明显高于其他地区;西北和华南地区存在新能源制氢潜力与加氢设施建设之间短期发展不均衡的现象;2030年我国各省份新能源制氢效率和潜力较2017年都有所提升。最后,依据评价结果提出改善我国氢能产业发展的对策建议。