浅析电力金具的耗能和经济选型

针对不同材质型号的电力金具耗能不同这一客观事实，采用费用现值和追加投资动态回收期两种财务指标，论述了计及耗能时电力金具经济选型的方法。     

分包工程的造价控制

人们通常会有个误解：认为工程项目实行了施工分包,就会把包括地质、水文、气象、变更和物价上涨等引起费用增加等风险全部或部分地转移给了分包商。施工分包,不可避免地会出现变更项和新增项,而分包单位能够承受风险的能力有限,往往会直接提出涨价要求或者采取怠工、停工等消极方式来达到追加费用的目的,不利于项目的进度。因此工程造价控制就显得十分重要。     

提高节点阻抗矩阵支路追加法的效率分析

针对电力系统分析计算中形成节点阻抗矩阵常用的支路追加法 ,提出了一种基于高斯消去法的连支支路追加方法 ,其公式即便于记忆 ,也便于编程。分析了影响支路追加法速度的因素 ,并提出了提高支路追加法效率和速度的方法     

日修订家电回收法 成立非法丢弃防范基金

10月6日,日本环境省和经济产业省修订《家电回收法》,自2009年4月开始追加液晶电视、等离子电视、干衣机3类家电纳入法定回收义务范围。消费者在进行上述三类家电商品更新换代淘汰旧机时,将与显像管电视、冰箱冰柜、空调、洗衣机等4类家电一样向制造厂商支付再利用费用。     

形成节点阻抗矩阵的节点编号顺序优化算法

在分析传统的支路追加法形成节点阻抗矩阵缺陷的基础上,提出了虚拟接地支路和连支度的概念,采用增加虚拟接地支路的方法使电网节点和支路的追加顺序不受任何条件的约束,并通过节点对连支度的比较确定电网节点和支路追加顺序,从而显著降低了形成节点阻抗矩阵的计算量。最后用实例验证了该方法的有效性。     

空调系统连接管加长后制冷剂追加量的工程计算方法

本文对空调安装工程中连接管加长后需要追加制冷剂的问题进行了研究,对空调系统的运行参数条件进行了理想化的假设,在假设的条件下结合工程经验对连接管加长后需要追加制冷剂的质量进行了推算,并得出了空调产品常用液管与气管的搭配选型下制冷剂追加量的推荐值。     

节点导纳矩阵和阻抗矩阵的互感支路组整体追加方法

在以支路追加法形成节点导纳矩阵和节点阻抗矩阵的过程中,互感支路的追加远比非互感支路复杂,因此提出以支路组为单位的节点导纳矩阵及节点阻抗矩阵支路组追加法。该方法将相互之间有互感耦合的支路分为一组,应用所推导的追加公式以整组互感支路为单位直接追加到节点导纳矩阵和节点阻抗矩阵中,使得计算方法简单统一,可显著减少计算量,提高计算效率。最后通过算例验证和比较了所提方法的实用性和有效性。     

并联电容器组使用两种电抗率混装时的涌流计算问题

本文阐明了在装有串联电抗器的情况下计算追加投入时的涌流必须考虑电源的影响,并提出用一个公式,统一对单组投入及追加投入的涌流进行计算。在此基础上,提出两种电抗率混装时的涌流计算方法。     

能量函数方法在大电网追加紧急控制中的应用

针对离线制定的安全稳定控制策略可能出现方式失配的情况,提出一种基于能量函数的在线追加紧急控制策略。该策略依赖于描述系统不稳定情况的能量函数指标,基于SCADA/EMS和PMU实时数据,将能量函数方法和轨迹预测方法相结合,实现大电网的紧急追加控制。并给出系统发生故障时的追加控制操作方法和紧急控制中切机控制的决策实施具体方案,为电力系统安全稳定运行提供一种可行的思路和方法。     

三相高压电能表错接线检查分析

本文论述了高压电能表及其附件的错接线检查、分析和电度追加方法。     

Dead calm [requirement for wind power generation storage devices]

While wind generation is fast proving to be a valuable option in combating so-called greenhouse effects, hidden costs exist. Extra costs due to additional reserve capacity as well as inefficiencies during conventional plant operation are often ignored. This article analyses wind power production figures for the UK and suggests that economically efficient storage devices could be used to mitigate the uncertainties in wind power generation. Such devices could shift generation from low demand periods to peak demand periods, reduce or even remove the need for additional reserve and change the nature of wind generation from 'reserve sinker' to 'reserve provider'.     

Avoided costs: Ontario Hydro's experience

Ontario Hydro regularly estimates avoided costs primarily for use in evaluating some design, operating, planning, and domestic marketing alternatives. Avoided costs reflect the expected cost of increased or decreased use of existing facilities or the expected cost of delaying or advancing additional resources. The author explains how Ontario Hydro calculates avoided costs. He includes a brief review of various methods proposed for calculating them. He refers to the theoretical basis for the methods used and lists in detail the assumptions used by Ontario Hydro     

风能并网发电经济性研究

根据风能并网发电的特点,分析影响风能并网发电的经济性因素,即风速、初始投资成本(包括并网成本)、运行和维护成本、输变电距离、环境等;建立风速计算模型和风电机组出力模型。在此基础上提出年附加输变电成本、输送到付费用户每千瓦时的单位能量成本、节能效益及减排效益4个符合风能并网发电特色的经济性评价指标。并通过8 760 h风速和风电机组出力的蒙特卡罗模拟进行算例分析和比较。研究结果表明,风能并网发电的经济效益显著,评价指标具有正确性和可行性。     

Costs for electric-power ancillary services

Ancillary-service costs comprise a substantial share—as much as 25 percent—of total bulk power costs. The cost levels and the great variation in the cost of different services suggests that additional work is needed to define each service and identify how much of it is required.     

A Maintenance Model for Clinical Engineering

The numbers presented here for an equipment maintenance model are derived from a mix of soft data and intuition based on experience. They relate best to university hospitals in the 250-400-bed range. They relate better to numbers of devices than number of beds. In summary, they are: 1. Ideal technician workload = 400 to 550 devices. 2. Average technician productivity or ``hands-on' maintenance time = 75%. 3. Average dollar value per device = $2,000. 4. Annual in-house maintenance ratio = 5% to 7% of value plus parts in excess of $200/item. 5. Effective rate per hour = $35 to $45/hr (depending upon region and labor costs in that region). 6. In-house maintenance costs should be less than outside costs. However, the in-house department should be aware of cost-effective outside options and employ them as appropriate. 7. Appropriate resources. 250 sq ft/technician, $20,000 capital equipment/technician, and $15 to $25/device in supplies. 8. Clinical engineers. One engineer to start the service and one engineer for each three additional technicians added. 9. Clerical support. One clerical FTE for a minimum 3 technician department, and one additional clerical FTE for each additional 1.5 FTE clinical engineers or each additional 5 FTE technicians. 10. Annual maintenance = 2.5 hr/device. (When clinical devices are distinguished from nonclinical devices, averages are 3 hr/clinical device and 2 hr/nonclinical device.) As clinical engineers, BMETs, and their departments gather experience to support or modify these numbers, I encourage them to share their findings in an experience pool available to all.     

基于谐波成本与超标惩罚的谐波定价模型研究

由谐波造成的经济损失和因治理而形成的额外投资共同构成了谐波成本,谐波成本是谐波定价的基础.基于谐波造成的经济损失和谐波电流超标的影响分析,提出了谐波经济损失补偿电价和谐波电流超标惩罚电价的谐波定价模型,分析了模型的合理性,并结合算例讨论了可行性.     

Motivations and options for deploying hybrid generator-plus-battery projects within the bulk power system

Growth in U.S. utility-scale hybrid battery projects suggests potential advantages currently outweigh disadvantages. Today’s 4.6 GW of hybrid capacity is accompanied by 14.7 GW in the immediate development pipeline, and 69 GW in select interconnection queues. Analysis using wholesale market prices finds that additional revenues from adding a 4-hour battery to solar can exceed additional costs. However, realizing hybrid projects’ full value depends on nascent strategies for integrating them in current/future wholesale market design paradigms.     

An economic evaluation for an autonomous independent network of distributed energy resources

This paper proposes a method for the economic evaluation of an autonomous independent network of distributed energy resources. There are existing proposals for such networks; the system that we are proposing and analyzing in this study is called Microgrid. Microgrid is a new framework of power delivery system that is formed by small, modular generation systems connected to each other to create a small autonomous grid. This paper estimates the total costs to consumers in a Microgrid with optimized operation of distributed generators and energy storage systems. This estimation includes not only installation and operation costs but also the additional expenses to construct the Microgrid itself. In addition, power interruption costs are also taken into account to consider the reliability enhancement created by the Microgrid. The paper attempts to determine whether or not it is economical for consumers to form this kind of autonomous independent network.     

考虑电动汽车移动储能的微电网调度

将电动汽车电池集成到微电网可以为微电网提供额外的电能存储,其收益取决于市场电力价格、电动汽车充电状态和进站/出站率等因素.假设微电网由热力机组、可再生能源和含储能设施的停车场组成.文章提出了一种考虑电动汽车移动储能特性的能源管理优化模型,模型的目标函数是最小化预期的总运营成本,包括前期市场的能源购销成本、热力机组的启停成本及发电成本、电池的磨损成本以及在每个场景中与当地电力分销商进行电力交换的成本等.采用Benders分解算法对模型进行求解,并利用修改的14节点系统进行了仿真验证.仿真结果表明:利用电动汽车电池的储能特性有效地降低了微电网的总运行成本.     

Prepayment for electric service with the PowerStat

The PowerStat is an electric power information and control system designed to reduce electric costs to the consumer. The system eliminates conventional meter reading and billing schedules and allows the consumer to pay for his electricity at any time and on any regular or random schedule desired. The PowerStat is owned by the utility company and installed in each residence or place of business to provide the consumer with a continuous display of his electric power status. It also shows the amount of electricity available and alerts the consumer when it is time to buy additional power. Testing and evaluation have been underway since February, 1986. Consumer response has been excellent, and early results indicate some reduction in power costs