Electrical characteristics of new three-phase traction power supply system for rail transit

A novel three-phase traction power supply system is proposed to eliminate the adverse effects caused by electric phase separation in catenary and accomplish a unifying manner of traction power supply for rail transit.With the application of two-stage three-phase continuous power supply structure,the electrical characteristics exhibit new features differing from the existing traction system.In this work,the principle for voltage levels determining two-stage network is dissected in accordance with the requirements of traction network and electric locomotive.The equivalent model of three-phase traction system is built for deducing the formula of current distribution and voltage losses.Based on the chain network model of the traction network,a simulation model is established to analyze the electrical characteristics such as traction current distribution,voltage losses,system equivalent impedance,voltage distribution,voltage unbalance and regenerative energy utilization.In a few words,quite a lot traction current of about 99%is undertaken by long-section cable network.The proportion of system voltage losses is small attributed to the two-stage three-phase power supply structure,and the voltage unbal-ance caused by impedance asymmetry of traction network is less than 1‰.In addition,the utilization rate of regenerative energy for locomotive achieves a significant promotion of over 97%.

The Faithful Representation of Electrical Energy Sale and Purchase Agreements Under International Accounting Standards/International Financial Reporting Standards （IAS/IFRS）

This article aims at giving a contribution to the issue of accounting electrical energy sale and purchase agreements in accordance with the faithful representation principle. To this end, it must be ascertained whether electrical energy is bought/sold for an industrial use exclusively, so that the relevant transaction will be accounted as a normal purchase/sale, or through the lease of the relevant production plant, which would require the supply contract to be accounted in compliance with International Accounting Standards （IAS） 17 ＂Leasing＂. Alternatively, it must also be ascertained whether the relevant party is implementing financial trading strategies, as in such hypothesis, the supply contract is to be accounted as a financial instrument according to International Financial Reporting Standards （IFRS） 9/IAS 39 ＂Financial Instruments＂. Finally, the modalities used by a number of companies listed on European regulated markets to account such kind of contracts will be analyzed.

Optimal Trading Decision-Making of Power Supply Chain under Renewable Portfolio Standards

Under the background of implementing renewable portfolio standards and the ever-improving tradable green certificate scheme,the increasingly environmentally-friendly preference of power users is leading to changes in electricity demand,which,in turn,is driving changes in the decision-making behaviors of various actors in the power supply chain.Based on this,with the goal of pursuing maximum profit,consumer-power-demand functions have been introduced with some consideration of the factors of consumer preference to establish an optimal profit model for each trading subject in non-cooperative states of the power supply chain,under the constraints of meeting renewable energy portfolio standards.Here,the optimal strategy of each trading subject is presented by adopting the reverse induction method.Furthermore,examples are used to analyze factors such as the influence of environmental protection preferences,quota ratios,price substitutions,and market demand as well as the optimal profit of each trading subject in view of providing a reference for the decision-making in the power supply chain trading subjects.

对有关电能计量若干问题的思考

文中基于论证和较全面分析,就不同场景下电能计量所关注的截然不同的问题、更好利用大数据去构建电能表检验新方法、动态电能计量研究面临新挑战、关注超谐波电能计量、不宜将电能计量装置与电能表简单划等号,以及测量准确度不同于测量精度等六个问题,阐述了作者的观点和认识,旨在对开展相关研究,以及更清楚理解相关测量方法及概念等起到促进作用。

Impact of Implementation Energy Efficient Appliances in Palestinian Market

Recently, Palestine has been willing to improve its energy efficiency action plan and policies. As the Electrical demand for energy is increasing in Palestine, improving energy efficiency can be considered as an efficient way to achieve reductions in energy consumptions. In this respect, energy efficiency action plan and its strategies must be designed to overcome existing market barriers against using energy efficient appliances in residential and commercial sectors in Palestine. This study provides background on the benefits of stakeholders and steps needed to support energy efficiency standards and labeling in Palestine. Furthermore, this study attempts to predict the techno-economic impact of implementing high efficient electrical appliances in Palestine. Survey-based analyses from 300 households were conducted in 2019 to estimate residential sector electrical appliances usage, behavior and their knowledge in electrical appliances labels and standards, the study aims also to estimate the perception and willingness of Palestinian householders to shift towards more energy efficient choices. The study will focus on 8 electrical appliances that constitute a major share of the electricity used within households and commercial sectors in Palestinian market.

Toward a Test Protocol for Conducted Energy Weapons

Conducted Energy Weapons (CEWs), such as those manufactured by TASER International Inc., are seeing increased use by law enforcement agencies as a less lethal force option;but, at the same time, these weapons are also seeing an increased level of concern in terms of their safety of use. In order to enable consistent evaluation of CEW performance, a systematic protocol for testing the electrical output of such weapons is required. In this paper, we propose a test specification for CEWs, designed to calculate the key performance and electrical safety parameters. The weapon is fired into a specified load, and current or voltage data are acquired, from which a set of electrical parameters are calculated and recorded. The protocol is based on experience of testing 6000 CEWs in the labs affiliated with the authors. This test protocol is designed to enable systematic testing, evaluation and research on CEW’s, including identification of weapons which are out of specification, determination of changes in weapon characteristics over time, and evaluation of weapons post-incident. Based on the proposed test protocol, we evaluate and report on electrical output produced by 208 X26TM and128 M26TM TASER? weapons. Results are shown in terms of proposed summary parameters and in terms of manufacturer’s performance specifications.

量子功率标准综述:原理、现状及展望

随着国际单位制(International System of Units,SI)量子化变革的稳步推进和广域落地实施,以更加准确、稳定的量子计量标准替代实物计量标准,已成为计量学领域的重点攻关任务之一。量子功率标准对电能的精准计量将发挥关键作用,可有力保障电能贸易结算、电碳交易的公平和公正。首先,该文从交流功率标准和直流功率标准两方面,对当前国内外功率标准研究现状进行了综述。对于交流功率标准,分别阐述了工频交流功率标准和宽频交流功率标准的基本架构、测量原理,指出基于热电变换器的交流功率标准可实现工频和宽频(百kHz)交流功率的高准确度溯源,而国内外已有交流量子功率标准的工作频带一般不超过400Hz,需开展宽频交流量子功率标准研究;对于直流功率标准,国内外还处于初步研究阶段,由于当前尚缺乏对直流电压、电流信号的标准化定义,导致应以何种形式的直流功率信号作为标准被测对象尚不明确,无法为构建直流量子功率标准提供方向性指导。随后,该文对比分析了不同的功率标准,给出了对当前构建功率标准所存在问题的思考,并试对交、直流功率标准的未来发展做出展望:随着宽频量子电压标准技术的发展与进步,有望实现宽频量子功率标准;同时,开展宽频、宽量限电压、电流放大器和比例技术的研究,是实现高准确度交、直流量子功率标准的重要前提。

高压电能计量现场校准装置及其不确定度分析

随着新建产能增加和新技术的不断应用,油田用电量逐渐增大,对高压电能计量设备进行科学的评价,可以对设备运行情况提供可靠的数据支持,以节省和减少油田的能源消耗,进而为设备维护更新、技术改造、新建项目等提供决策支持。高压电能计量现场校准装置,采用高压三相标准功率源和多功能标准表、V/V转换器、I/V转换器组合的方式对高压电能计量设备进行整体校准,对装置进行不确定度分析,使装置在现场校准的过程中能够保持稳定的性能指标。

基于某特殊铁路标准的电力机车耐撞性设计方法

为了保证电力机车被动安全的普遍适用性,基于某特殊铁路标准,以某型电力机车车体为研究对象,开展了电力机车耐撞性设计方法研究。首先,在分析研究相关机车耐撞性标准的基础上,确定了符合特殊标准的碰撞工况;然后,开展了基于碰撞能量管理的电力机车车钩缓冲装置能量配置研究;最后,在建立电力机车碰撞动力学与有限元模型的基础上,对比分析了典型工况下基于碰撞能量管理设计前后机车的耐撞性指标。结果表明:碰撞后的车体自身平均加速度、车厢纵向永久变形量和门窗对角永久变形量等各项耐碰撞性能指标均能满足相关要求,验证了机车碰撞能量管理设计的合理性与有效性,提升了该型机车的耐撞性能。

基于不同标准的电动汽车能量消耗量生产一致性判定对比研究

对比分析了国家标准GB/T 18386.1-2021与欧洲标准(EU)2018/1832中对于电动汽车能量消耗量生产一致性判定的试验流程、统计量计算与生产一致性判定方法的差异。根据两种标准的不同规定,分别对某一型号的纯电动汽车进行了相关的生产一致性试验。结果表明,按照GB/T 18386.1-2021标准中生产一致性合格判定准则,该型号纯电动汽车可判定为合格;按照(EU)2018/1832标准中验证生产一致性合格判定准则,该型号纯电动汽车可判定为通过验证。

新型电力系统下直流电器附件标准体系研究

直流电器附件是新型电力系统中的重要基础设施之一,是实现直流供电电源与直流用电负荷之间互联互通的重要部件,其应用端、生产端、监管端均对标准提出了迫切需求,亟需构建一套契合新形势下的直流电器附件标准体系,指导直流电器附件相关技术标准的研制,引导行业有序发展。

建筑电气节能发展导向下电气节能标准的应用研究

随着人口的增长和经济的发展,社会对能源的需求日益增大,能源的快速消耗已经成为全球性问题。传统的能源资源越来越难以满足现代发展的需求。因此,如何有效地利用现有的能源资源成为了当前亟待解决的问题。文章将从电气节能标准的理论基础出发,在建筑电气节能发展导向下,对电气节能标准进行分析,为促进电力行业的可持续发展提供有益参考。

促进我国可再生能源电力发展的政策框架研究

在对世界各国的可再生能源政策体制和实践进行综合分析的基础上,结合我国的国情、法律体系、可再生能源发展状况以及我国电力工业发展与电力体制改革进程,分析各种促进可再生能源产业政策在我国的可行性,提出中国可再生能源发展分3步走的规划方案,初步分析各步骤之间的合理衔接,为我国制定和完善可再生能源政策提供借鉴。

一种电能计量标准期间核查方法

通过对选定的电能核查标准的测量,利用被核查标准的最大允许误差和校准证书给出的校准结果及其不确定度,来确定核查测量控制图的上、下控制界限和警戒线,利用Excel电子表格绘出这些控制界限,使每次核查测量结果在图中直观准确地反映被核查标准的误差和变化方向及大小,该结果也可作为计量标准稳定性考核的依据。

公共信息模型拆分与合并应用研究

为了更好地解决电力系统交换模型数据的问题,更好地实现部分模型传输,在基于IEC61970系列标准中的公共信息模型(CIM)及国内两次互操作实验的基础上,提出了进行CIM拆分与合并的基本应用原则。基于该原则,在原有互操作程序的基础上完成了各种拆分合并实验,并用IEEE 14节点数据进行了测试,结果令人满意。该项研究成果已应用于实际系统,并取得了很好的效果。

10kV／1000A高压电能计量标准及其量值溯源的研究

为了保证高压电能测量量值的准确可靠，提出了建立10kV高压电能计量标准及其量传系统的新方法，以实现高压电能计量器具的室内计量检定，进而实现电网高压电能计量器具的量值溯源。基于L／V和V／V技术，研制了高压电能计量标准，并对研究成果进行了不确定度分析及溯源验证，其三相电能的测量准确度达到0．02％；以高压电能计量校准装置作为被检对象，其三相电能的测量准确度在功率因数P，为0．5时达到0．12％。

数字化电能表检测装置设计

为了适应数字化变电站的快速发展,浙江省电力试验研究院开发了数字化电能表检测装置。本文介绍该装置的设计方案、数据发生原理、系统结构框架、装置的功能和装置的特点。针对数字化电能表的特点,该装置在传统检测项目的基础上增加了许多新的功能。该装置适用于检测在数字化变电站中使用的数字化电能表。

基于局部能量的电容层析成像图像融合方法

针对电容层析成像技术的"软场"效应和病态问题对重建图像精确度的影响,在分析电容层析成像基本原理和成像算法的基础上,提出了一种基于局部能量的电容层析成像图像融合方法。该方法以线性反投影、Landweber和共轭梯度算法作为图像重建的基础,利用各个图像的互补特性,经对重建的图像小波分解后,分别采用基于局部能量和加权平均算子融合规则对分解后图像的高频系数和低频系数进行图像的融合,得到准确度更高的成像结果。仿真实验结果表明,融合后成像精确度得到明显提高,缩小了误差,图像更接近原型,为ECT图像重建的研究提供了一个新的方法。

国际上鼓励可再生能源发电制度的利弊分析

由于矿物能源资源的有限性和全球环境压力的增加,世界上许多国家都提高了对可再生能源重要性的认识,出台了不少新的政策和措施。我国政府近些年来一直积极探索以强制性手段保障可再生能源发展的有效机制,文中对世界各国的可再生能源政策体制和实践进行了系统的综述和利弊分析。

0.1级便携式单相多功能电能表检测系统研制

针对国内现场检测多功能电能表标准装置相对缺乏的情况,研制0.1级便携式单相多功能电能表检测系统。该系统由功率源、标准表、多功能检测模块相互协调组成,其中标准表接收功率源输出的信号,多功能检测模块进行检测分析。多功能检测模块的时间设计采用高准确度GPS为主标准、高稳晶振时间为副标准的双标准设计,测量不确定度可达10^(–6)。试验结果表明:该系统各项指标的准确度达到0.1%,可实现对单相多功能电能表的现场检测。