CyDER – an FMI-based co-simulation platform for distributed energy resources

The increased integration of distributed energy resources (DERs) is bringing a number of challenges to the power grid. These include reverse power flows in distribution systems and potentially transmission systems and grid stability. So far, specialized tools have been developed to capture some of the impact of DERs at the distribution level. However, distribution system operators lack visibility into the overall system conditions. Furthermore, the impact of increasing DERs is not limited to the distribution level but also influences the transmission grid. To support the planning and operation of the grid, we developed a co-simulation platform called CyDER (A Cyber Physical Co-simulation Platform for Distributed Energy Resources in Smart Grids) that integrates various domain-specific simulation tools. CyDER is based on the functional mock-up interface standard. This paper gives an overview of CyDER and demonstrates its use based on two applications.     

Power quality improvement of grid-connected wind energy system using facts devices

ABSTRACT

The increased penetration of wind power into the grid will save the fossil fuels and reduce the impact on the environment; however, it also presents many challenges to power system operation and control, system stability and power quality. In this paper, the use of static compensator (STATCOM) with battery energy storage system (BESS) is to enable smooth and the proper integration of wind energy system to the grid is taken as the main objective. This work presents a novel controller for an integrated STATCOM-BESS for grid-connected wind energy system. The simulation of the proposed system is done in Simulink with hysteresis current controlled pulse width modulation-based controller, which is in the IEC 61400-21 standard. It is observed that the STATCOM with BESS, operated with the specified controller, provides reactive power support, good harmonic mitigation as well as maintaining the source current the voltage without any phase angle difference. The experimental setup composed of Matlab-dSPACE DS1104 interface for generating the gate pulse, isolation and gate driver circuit, and the three-phase inverter is created and the system is tested for various combinations of R load and R-L load, and the measurements are recorded using FLUKE 434 energy analyser.     

State-of-the-art research on micro grid stability: a review

The usage of renewable energy resources (RES) in energy is receiving great attention as a solution to the problem of a shortfall in electrical energy. Application of RES in a generation system is done with diverse outlines, amongst others in a micro grid system. Employment of micro grid systems offers numerous benefits both for the consumer as well as for the utility provider. Voluminous micro grid expansions are carried out in more than a few countries, because it offers healthier power quality and furthermore it is ecologically friendly. Even though its adoption is growing steadily, there are still several hurdles to proficiently design, regulate, and operate micro grids when linked to the grid, and as well when in the islanded mode, and wide-ranging investigation activities are on-going to confront the issues. It is essential to consider across-the-board opinions of the micro grid amalgamation in a power system network. This paper presents a review of issues in relation to micro grid stability and offers an account of study in areas related to micro grids.     

矿井通风机无刷同步机电控系统应急方案的研究

介绍了某矿井通风机房电控系统及无刷同步机电控系统的结构,针对无刷同步电动机系统启动时间较长、对电网波动敏感跳车等影响通风机稳定运行的因素进行了分析,主要研究了应急运行方案,并对具体的设计方法作了阐述,以确保通风系统的可靠性。     

电力自动化系统中的故障分析与处理技术

当前对电力使用过程中的自动化要求越来越高,电力自动化作为电力公司长久发展的必然要求,也是提升电力企业工作效率和工作质量的有效途径。电力自动化系统在运行过程中存在的一定的故障问题,需要对其进行分析处理,从而提升电网运行的稳定性。     

Smart grids: energising the future

Electrical power systems are the backbone of industry, society and current civilisation. Power engineers have accumulated the necessary skills and procedures, to enable them to operate the system in the most reliable way possible. The main principles of system operation have not changed much, despite the rapid developments in power electronics, computing, information and communication technologies. This paper surveys existing power networks and their limits in meeting modern developments and environmental concerns. There is an evaluation of the impacts of deployment of new low carbon technologies such as distributed generation and electric vehicles on existing networks, together with the main drivers for change and features of the new concept of the ‘smart grid’. The paper also examines the challenges and benefits that the ‘smart grid’ will bring, and describes the enabling technologies.     

分布式光伏并网系统运行中存在的问题

光伏建筑一体化作为分布式光伏电站的一种存在形式,越来越受到关注。分布式光伏系统接入配电网运营后,改变了传统电网的结构,从过去的无源电网转变为有源电网。由于光伏发电系统输出的电能具有间歇性、不稳定性等特点,必然会对所接入配电网的电能质量、潮流分布、短路电流、保护协调、孤岛效应、光伏逆流等方面产生不同程度的影响。根据国家电网公司颁布的《分布式电源接入系统典型设计》的要求,针对分布式光伏并网系统运行中存在的问题,提出了改进措施和具体的技术要求。     

微涡旋混凝工艺用于醴陵铁路水厂改造

针对网格反应池存在的易积泥、易堵塞等不足,介绍了微涡旋混凝工艺在醴陵铁路水厂改造工程中的应用。改造后的运行结果表明,此工艺具有反应效率高、反应时间短、出水水质优、节约能耗、改造施工简单方便等优点,具有一定的推广价值。     

Impact on power quality due to large-scale adoption of compact fluorescent lamps – a review

The demand of electrical energy has grown tremendously in the last couple of decades across the globe. The energy conservation and management has attracted the attention of stake holders for efficient utilisation of the resources. One of the major steps taken by the authorities towards conservation of electrical energy is replacement of incandescent lamps (ILs) by compact fluorescent lamps (CFLs). CFL uses electronic circuit for its ignition, making them a non-linear load on utility grid. Large-scale replacement of ILs has enormous effects on utility grid in terms of power quality. This paper reviews the work conducted by several researchers investigating the effect of using CFLs on power quality. Basic terminologies related to power quality is defined. The experimental results elaborate the pollution on the grid in the term of total harmonic distortion in current due to adoption of CFLs. The methodologies of harmonic measurement system are reviewed. Different software used for the analysis is presented. The paper will help the researchers to receive a comprehensive overview of power-quality issues.     

网架挠度自动测试系统

本文介绍了一种新型的网架挠度自动测试系统。作者采用电感调频式位移传感器和单片微型计算机组成数据检测和处理系统,研制了刚性和柔性两种参考连接体系,从而实现了网架挠度测试数字化和自动化。该系统具有通道多、测量范围大、精度高、工作可靠、设备轻巧、使用简便等优点,已通过6项工程应用,表明效果明显。     

交流电动机并网控制器在建筑电气中的应用

交流电动机是广泛用于各领域的重要动力设备,电动机数值可观的启动电流及其对供电系统的影响长期困扰着人们,传统的各种启动方式都有这样或那样的弊端.自变频调速器问世以后,交流电动机的软启动很好地解决了这一问题.但当前大量出现的问题是电动机升速到接近额定转速切换到电网电源过程中,常常造成很大的冲击并引起电动机保护跳闸,使切换失败.交流电动机并网控制器很好地解决了这一问题,实践证明电动机的电源切换是能无扰动平滑切入电网的.     

土壤中石油类的监测方法

电力GIS是电力自动化和电力设备安全运行的基础,而电网设备数据采集是GIS系统的核心,本文研究了电网设备数据采集的技术和方法,同时对坐标转换技术也进行了研究,对今后电网设备数据采集或相关的数据采集提供了有效地技术保证。     

Wind power penetration impact on power system frequency

The incorporation of large amounts of wind power in power systems poses huge challenges. Especially with the growth of wind power generation, more rule reserves would be essential, the capability of the power system to offer classical regulating power would be reduced and the dynamic stability of the grid frequency under large oscillations would be compromised. In this paper, to investigate the integration of large-scale wind power generation in power systems and its active power control, a novel method and solution dealing specifically with the electric frequency stability and high wind power penetration is presented. So, the impacts of wind power on a balancing area's frequency control specification and studies the wind power impacts power system control. The proposed method has been applied to a three-area Automatic Generation Control model to verify these impacts. The simulation results obtained show that power system control indices deteriorate as wind power penetration increases.     

浅析电网规划设计的关键问题与技术

电网规划设计决定电力基础设施的建设水平,也影响经济的发展,因此,本文对电网规划设计的几个关键问题--负荷预测、电网的网架分析与运行、电网的规划评价等方面进行了分析和研究,提出相应的解决方式。     

基于扎根理论的电网新技术推广应用评估模型研究

新技术在我国电网工程建设实践中不断得到推广应用,应用经济效益成为其推广应用范围和力度的主要依据,构建科学、合理的应用经济效益评估体系因而具有重要的现实需求和理论研究价值。基于扎根理论对典型电网工程项目的有关人员进行半结构化专家访谈,筛选并凝练出支撑电网工程新技术推广应用的经济效益评估结构维度及其作用模型,从“工程技术投入-工程技术应用经济效益-企业经营效益-社会经济效益”4个方面阐释了理论模型;构建一套包括4个一级指标、6个二级指标和11个三级指标的评估体系。最后,选取典型案例进行验证分析,为电网工程建设新技术应用经济效益评估提供参考。     

三遥系统在水源地的应用

以河津电厂水源地遥控系统为例,介绍了三遥系统在水源地的应用,分别阐述了MRC型无线测控系统性能及存在问题,JSY型无线测控系统特点及运行情况,并提出系统运行注意事项及故障排除方法,以期指导实践。     

Seismic performance assessment of electric power systems subjected to spatially correlated earthquake excitations

Electric power systems play a critical role in assuring modern society’s functionalities. Earthquakes are one of the most destructive natural hazards that affect the serviceability of electricity transmission systems. The earthquake excitations applied to each component of a power system (e.g. plants, substations and transmission lines) are spatially correlated by nature due to common causes. Yet, limited attention has been paid to the impact of this spatial correlation on the power grid seismic performance. This article presents an approach for estimating the seismic performance of large-scale electric power systems subjected to spatially correlated earthquake ground motions. The network flow theory is used to model the power flow allocation over the grid components, and a stochastic ground motion model is employed to represent the spatial characteristics of earthquake excitations. The proposed method is illustrated through the seismic performance assessment of the national power grid of Italy. The overall vulnerability is measured and evaluated through a proposed metric, and the critical components of the grid system are identified. The impact of spatial correlation of earthquake ground motion on the grid system’s post-hazard performance is also investigated.     

A new approach for applying the in-situ Schmidt hammer test on a coal face

The indirect Schmidt hammer test is used to determine the mechanical behavior of rock materials. The method has so far been widely applied to intact rock, and therefore researchers have developed procedures for its use on rock cores and blocks. However, there is currently little information about using the Schmidt hammer for in-situ testing. The purpose of this study was therefore to evaluate the application of the Schmidt hammer test in-situ on a coal face. In this study, a measurement area of 72 m² was selected in the center of a 330 m² longwall face. The main measurement area was divided into a grid system, with each grid section having an area of 0.375 m². The tests were conducted as a single hammer impact at the center of each grid section. One thousand nine hundred and sixty-five records were constructed using the data obtained from 10 face positions, and these were used for statistical analyses. The statistical results suggested that the total number of tests carried out on the main measurement area was more than the minimum required. An equation was then developed that not only gives the appropriate test number, but also provides information about the grid system. Hence, a new approach is proposed for determining the optimum grid system and test number for in-situ testing of coal faces.     

Efficient pricing for European electricity networks – The theory of nodal pricing applied to feeding-in wind in Germany

This paper applies nodal pricing as an economic approach to efficient use of electricity networks utilization for the fairly large German grid. We combine a straightforward welfare maximization with the technical specificities of electricity flows on a realistically large network. The nodal pricing model is applied in order to analyze the impact of extended German wind power production on the power grid. The paper shows that economic modeling, taking into account physical and technical constraints, makes important contributions to the assessment and optimization of system configuration and operation.     

铁路客站光伏并网发电项目太阳能电池选型比对

以京沪高速铁路上海虹桥铁路客站太阳能光伏并网发电工程和天津西站太阳能光伏并网工程为例,在两个电站选用不同类型太阳能电池的基础上,对其性能及在运行过程中产生的问题进行了分析和比较,并对其优缺点进行了阐述,为今后铁路光伏并网发电项目太阳能电池选型提供借鉴。