A Novel Bidirectional Interaction Model and Electric Energy Measuring Scheme of EVs for V2G with Distorted Power Loads

With the increasing demand for petroleum resources and environmental issues,new energy electric vehicles are increasingly being used.However,the large number of electric vehicles connected to the grid has brought new challenges to the operation of the grid.Firstly,A novel bidirectional interaction model is established based on modulation theory with nonlinear loads.Then,the electric energy measuring scheme of EVs for V2G is derived under the conditions of distorted power loads.The scheme is composed of fundamental electric energy,fundamental-distorted electric energy,distorted-fundamental electric energy and distorted electric energy.And the characteristics of each electric energy are analyzed.Finally,the correctness of the model and energy measurement method is verified by three simulation cases:the impact signals,the fluctuating signals,and the harmonic signals.

A new method of electric energy metering considering harmonic responsibility

Aiming at the shortcomings of the existing electric energy metering method,combining with the harmonic responsibility analysis model based on the reference impedance method and the idea of apparent power decomposition in IEEE Std 1459-2010 standard,two new metering indicators—billing active power and billing power factor are defined.A new electric energy metering method is proposed and its specific implementation steps are given.The simulation model is built in Matlab/Simulink,and three different examples are set up.Using the simulation data,the various metering indicators need to be examined by the existing electric energy metering method and the new electric energy metering method are calculated.The calculation results show that the new electric energy metering method not only overcomes the shortcomings of the existing electric energy metering method,but also is very easy to be popularized and applied.

Energy flow problem solution based on state estimation approaches and smart meter data

Accurate electric energy(EE)measurements and billing estimations in a power system necessitate the development of an energy flow distribution model.This paper summarizes the results of investigations on a new problem related to the determination of EE flow in a power system over time intervals ranging from minutes to years.The problem is referred to as the energy flow problem(EFP).Generally,the grid state and topology may fluctuate over time.An attempt to use instantaneous(not integral)power values obtained from telemetry to solve classical electrical engineering equations leads to significant modeling errors,particularly with topology changes.A promoted EFP model may be suitable in the presence of such topological and state changes.Herein,EE flows are determined using state estimation approaches based on direct EE measurement data in Watt-hours(Volt-ampere reactive-hours)provided by electricity meters.The EFP solution is essential for a broad set of applications,including meter data validation,zero unbalance EE billing,and nontechnical EE loss check.

Technologies Behind the Smart Grid and Internet of Things: A System Survey

Electric smart grids enable a bidirectional flow of electricity and information among power system assets.For proper monitoring and con-trolling of power quality,reliability,scalability and flexibility,there is a need for an environmentally friendly system that is transparent,sustainable,cost-saving,energy-efficient,agile and secure.This paper provides an overview of the emerging technologies behind smart grids and the internet of things.The dependent variables are identified by analyzing the electricity consumption patterns for optimal utilization and planning preventive maintenance of their legacy assets like power distribution transformers with real-time parameters to ensure an uninterrupted and reliable power supply.In addition,the paper sorts out challenges in the traditional or legacy electricity grid,power generation,transmission,distribution,and revenue management challenges such as reduc-ing aggregate technical and commercial loss by reforming the existing manual or semi-automatic techniques to fully smart or automatic systems.This article represents a concise review of research works in creating components of the smart grid like smart metering infrastructure for postpaid as well as in prepaid mode,internal structure comparison of advanced metering methods in present scenarios,and communication systems.

Simulation of District Cooling Plant and Efficient Energy Air Cooled Condensers (Part I)

In hot arid countries with severe weather, the summer air conditioning systems consume much electrical power at peak period. Shifting the loads peak to off-peak period with thermal storage is recommended. Model A of residential buildings and Model B of schools and hospitals were used to estimate the daily cooling load profile in Makkah, Saudi Arabia at latitude of 21.42°N and longitude of 39.83°E. Model A was constructed from common materials, but Model B as Model A with 5 - 8 cm thermal insulation and double layers glass windows. The average data of Makkah weather through 2010, 2011 and 2012 were used to calculate the cooling load profile and performance of air conditioning systems. The maximum cooling load was calculated at 15:00 o’clock for a main floor building to a 40-floor of residential building and to 5 floors of schools. A district cooling plant of 180,000 Refrigeration Ton was suggested to serve the Gabal Al Sharashf area in the central zone of Makkah. A thermal storage system to store the excess cooling capacity was used. Air cooled condensers were used in the analysis of chiller refrigeration cycle. The operating cost was mainly a function of electrical energy consumption. Fixed electricity tariff was 0.04 $/kWh for electromechanical counter, and 0.027, 0.04, 0.069 $/kWh for shifting loads peak for the smart digital counter. The results showed that the daily savings in consumed power are 8.27% in spring, 6.86% in summer, 8.81% in autumn, and 14.55% in winter. Also, the daily savings in electricity bills are 12.26% in spring, 16.66% in summer, 12.84% in autumn, and 14.55% in winter. The obtained maximum saving in consumed power is 14.5% and the daily saving in electricity bills is 43% in summer when the loads peak is completely shifted to off-peak period.

Research on the Recognition Method of Electric Energy Meter Lead Title based on the Fuzzy Image Processing

This article puts forward an automatic recognition algorithm of electric energy meter lead seals： firstly, the image will be histogram equalization, smoothing, binaryzation pretreatment, then according to the image characteristics of text changes, the system can quickly and accurately segment image from complex background, finally the system extract different dimension and the feature of English and Arabia using digital projection transform coefficient method and to identify the corresponding number by BP neural network, solves the problem of automatic recognition of electric energy meter lead sealing.

A Review of the Characteristics and Challenges of Electricity Distribution in Ghana: Case Study of the Northern Electricity Distribution Company

This paper presents a review of the characteristics and challenges of electricity distribution in Ghana with an emphasis on the Northern Electricity Distribution Company (NEDCo) in the northern half of Ghana. NEDCo is used as a case study due to the peculiarity of its geographical area of operation and customer characteristics which better highlights the challenges of electricity distribution in Ghana. NEDCo’s electricity distribution operations cover approximately 64% of the total landmass of Ghana and contain the most deprived communities and consumers, who are extensively dispersed. In addition to the scattered settlements, NEDCo has a predominantly lifeline customer base that pay tariffs below the average cost of service. These peculiarities, together with regulatory complexities, have contributed to many challenges, such as high system losses, high cost of service and poor network reliability, in the electricity distribution sector in Ghana.

Design and Implementation of a Single-Phase Energy Meter with SMS Controlled and Monitored Recharge Capability

The Nigerian power sector is faced with poorly organized billing and consumer relations management. Tariff billing and collection has been a big problem in some community in Nigeria even with the introduction of prepaid meters. The process of payment is cumbersome and stressful as consumers have to go and pay in banks and then take tellers to power utility office to confirm their power bills payment before they can recharge their cards. The major purpose of this work is to design and implement a convenient, cashless, automated and transparent electricity metering, billing and payment system. This project combines the power electronic meter with a communications network which in this case is a GSM （global system for mobile） network. Remote electricity billing is a unique concept, in which the electricity board can collect the consumed units＇ data from consumer on mobile phone using GSM network. A unique property of this system is that, the electricity board can disconnect or reconnect consumers from remote location through the mobile phone. As this project works on GSM network, the system can be controlled from any part of the country.

Determination of Energy Interchanged on the Tie Lines- Some Practical Issues

The quality of methods for determining energy transits on the tie lines （lines that connect two neighboring power system） can have significant impact on business activity of the TSOs （transmission system operators）. Existing law regulation is not enough precise regarding definition of methods for metering energy transits （energy interchanged between neighboring TSOs）. This paper analyses disadvantages of method for line losses metering with electric meters and suggests introduction of the measured value corrections.

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。

Design of PLC Centralized Meter Reading System

With the increasing development of urban housing construction and the rapid expansion of the number of inhabitants and independent electric energy meter, a variety of tariff systems are launched, meter reading metering becomes increasingly complex, and the traditional manual meter reading is already hard to adapt to new changes. This thesis studies the design of a centralized meter reading system. This program applies PLC technology for information transfer, which guarantees the stability of system carrier communication. This system is composed of electric energy meter, collector, concentrator and other hardware, as well as communication and management software of collection copies system. It is characterized by functions of power data collection, centralization, remote transmission, distance control, electricity analysis, line loss calculation, integrated query, and time-sharing billing. Its promotion and application will necessarily provide important technical means for power supply, property and urban utilities to improve their modernized and automatic management level.

Research on Intelligent Power Management System for Student Dormitory based on CAN Bus

This paper analyzes the actual situation of the electricity management about student apartments, and design intelligent energy student housing management system based on CAN bus. The system uses the field level, the underlying management level and upper management level three management system. Field level with a dedicated energy metering chip AD7755 and STM32F103 microcontroller with A/D conversion function as the core, to achieve real-time power measurement; via CAN bus timing or random read live energy data for monitoring electricity consumption of the apartment, investigate abnormal electricity, thus effectively limiting the students to use electrical power to achieve the modernization and automation of power management solutions student apartments.

Power ＂Smart Pricing＂ with and without Smart Meters

Over the past several years, the Taiwan Power Company has launched two smart pricing programs to assess the demand response of residential customers： the TOU （time-of-use） rate scheme and the DRI （demand reduction incentive） scheme. This paper discusses these two programs and evaluates their respective performances. We develop an efficient approach based on marginal cost pricing to redesign the TOU rate scheme. In our finding, the TOU price levels could be revised to encourage more customers to participate by enlarging the price gap. Moreover, the DRI scheme can be further improved in order to reach an efficient win-win solution among customers, the utility and society. This can be achieved via a careful design of incentive tariff discounts to take account of the time-of-use or location-specific features of the power supply/demand condition.

基于节能降耗的飞轮储能电力计量技术

飞轮储能电力计量技术,是一种将飞轮储能与电力计量技术相结合的创新型电力管理技术。飞轮储能以其高功率密度、长寿命、快速响应和环保无污染等特点,在电力系统中展现出巨大的应用潜力。而电力计量技术则是电力系统中的重要组成部分,用于准确计量和监测电能的使用情况。将两者结合,飞轮储能电力计量技术旨在提高电力系统的运行效率,优化资源配置,并推动电力行业的可持续发展。本文从节能降耗的角度出发,分析飞轮储能电力计量技术的应用研究情况,并从多个角度阐述未来飞轮储能电力计量技术的应用研究方向,以实现对电力系统的高效、绿色管理。

基于混合铁心的新型电流互感器研究

传统电流互感器铁心饱和会导致其二次电流波形发生畸变,进而可能影响电能计量的精度或引起继电保护设备错误动作,威胁电网的安全稳定运行。针对此类问题,提出了基于混合铁心的新型电流互感器(CCCT)。CCCT主要由混合铁心、二次绕组、二次电阻、磁场传感器与信号处理电路组成,其中混合铁心包含完整的内铁心与带气隙的外铁心,磁场传感器放置在外铁心的气隙中,其输出信号用于补偿发生畸变的二次电流。为验证该结构的有效性,进行了有限元仿真,制作了CCCT样机并进行了正弦交流电流、正弦半波电流、短路电流和直流电流的测量实验。有限元仿真与实验结果表明,CCCT在额定电流下的复合误差小于0.2%,稳态对称短路电流下的复合误差为2.04%,暂态短路电流下的峰值瞬时误差为4.25%,直流条件下输出与输入的拟合优度为0.999 9,既基本保留了传统电流互感器的测量精度,也具有良好的暂态响应特性与抗直流特性,可同时满足相关标准对测量、保护用电流互感器的精度要求,具备在实际工程中应用的潜力。

考虑电力市场化交易的电碳表计量及实现方法研究

电力间接碳排放是电力用户碳排放的主要来源之一,碳排放流是计算电力间接碳排放的重要方法。目前,基于碳排放流的计量理论尚未考虑电力市场化交易的影响,缺乏相应工程应用的实现方法,参与电力市场化交易的用户难以准确获得其用电量所对应的间接碳排放量。为解决这一难题,该文研究碳排放流理论的分布式电能实现方法,考虑电力市场化交易对交易双方及相关用户碳排放因子的影响,提出含电力市场化交易的电力系统源、网、荷全过程电碳排放量计量方法;并研究存在绿电交易、储能等情况下的电碳排放因子特点及计算方法。基于上述理论,研制了电碳表及其相关系统,并利用电碳表系统对某地电网部分实际拓扑进行分析,验证了所提方法的有效性及电碳表的实用性。

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。

基于台区电能量分层级解耦的电能表远程在线校准

针对电能表元件稳定性较差的问题,提出基于台区电能量分层级解耦的电能表远程在线校准方法。根据台区电能量分层级精准解耦原则,设置典型分层端口结构,求解微分解耦数据方程,实现对电能系数的计量处理。分别从AD转换器量化误差、数值求积截断误差、同步误差三个角度着手,分析校准参量的取值结果,完成远程在线校准设计。实验结果表明:采用所提方法的总线电能表示数、支线电能表示数与理想示数之间的差值水平均能得到较好控制,与三轴同步校准方法相比,更符合维持电能表示数稳定性的实际应用需求。

基于季节性指数平滑法的电能表需求预测分析

随着智能电能表大规模普及应用,电能表需求数量日益庞大,采用经验人工估计容易造成电能表临时短缺和库存积压等问题。基于计量系统中的电能表历史安装数据,采用简单季节性模型、Winters加法模型和Winters乘法模型,并结合LSTM模型对结果进行对比分析,比较不同模型的优劣,确定电能表需求预测最优方法。实证结果表明:Winters乘法模型预测效果最好,预测值平均误差为2.46%,预测趋势符合实际情况。Winters乘法指数平滑法能够对电能表需求变化趋势进行科学合理预测,可以协助供电公司更加高效开展电能表运营管理,提高计量资产利用效率。

电磁兼容检测用电能表检验装置的研制

针对电能表电磁兼容检测过程中辅助设备导致的测量重复率较低问题,基于场理论和电路原理,研制出性能优异的电磁兼容检测用电能表检验装置。本文研究了电能表电磁抗扰度实验过程产生电磁干扰的传输路径,分析了电能表检验装置承受的传导和辐射电磁干扰特性;结合干扰耦合方式、干扰频段和干扰强度,优化了装置电源驱动能力、干扰去耦能力、外壳电磁屏蔽效能和内部线缆布局;并提出合理的试验方案,验证了受干扰时装置的性能。最后,制订了电力行业标准DL/T 2556.2-2022《电力行业电磁兼容检测辅助设备第2部分:电磁兼容检测用电能表检验装置》,总结了电磁兼容检测辅助设备的技术要求和验证方法。