电力系统输变电设备状态检修分析

输变电设备的可靠运行对电力系统的安全影响巨大,通过分析现行设备检修模式的弊端,提出开展状态检修是电网发展的必然趋势。     

风力发电厂监控通信原理及模型——IEC 61400-25标准介绍

风力发电厂是一种分布式能源系统,需要设备与设备之间以及设备与电网之间有良好的配合。国际电工委员会最近制定了IEC 61400-25系列标准,该标准是IEC 61850标准的延伸,专门面向风电厂的监控通信。本文在概要介绍IEC 61400-25标准体系结构的基础上,重点介绍了风电厂监控系统通信原理、建模方法、信息模型和信息交换模型,并说明了如何把信息映射到特定的工业通信协议上的方法。     

一种连续供电系统双电源快速柔性切换方法

针对焦化生产行业一类负荷电能质量不合格或双电源切换不成功导致煤气异常排放问题,提出一种利用复合开关实现低压双电源快速柔性切换方法。该方法切换速度快,切换过程不产生冲击电流、过电压,保证设备正常运行。切换过程由协调控制器协调控制,各设备间信息流用IEC 61850模型表示,适应未来电网发展。实例分析说明了所述双电源快速柔性切换方法的实现和快速柔性切换复合开关的基本特性。     

风电场SCADA系统安全接口单元设计

随着信息技术在风力发电中的应用,风电场SCADA系统的安全稳定运行已变得越来越重要。文章结合风电场SCADA系统的安全需求,提出在SCADA Server中设计一个SIU以实现网络环境下对该系统的安全访问。SIU采用证书方式实现身份认证,通过验证MAC保证数据的完整性,并通过IEC 61850的虚拟访问视图执行访问控制策略。文章还给出了SIU的实现与应用实例。     

电网调度自动化系统信息品质分析新方法及其应用

电网调度自动化信息交互涵盖变电站过程层、间隔层、站控层、变电站与调控主站之间、主站与主站之间等环节,各环节不同应用间的信息通信标准具有各自的信息品质码。完整地解读了IEC系列标准与国内电力行业标准关于信息品质的规定。从调控数据交互信息品质应用角度考虑,介绍了IEC 62361-2标准内容,梳理了IEC系列标准(IEC61850、IEC60870-5-104、IEC60870-6、IEC61970等)及国内电力行业标准(DL476)关于信息品质码的基本原理。结合智能电网调度控制系统对基础数据的应用,提出了数据交互合成信息品质处理原则,详细分析了调控数据交互过程中不同通信规约之间信息品质映射规则。最后基于信息品质应用创新性地提出了一种基于取代服务的调控信息验收核对方法。     

宁夏电网输变电设备状态监测系统的实现

针对宁夏电网在线监测技术的应用现状,结合宁夏电网实际情况,对输变电设备状态监测系统建设运行的关键技术进行分析,提出了宁夏电网输变电设备状态监测系统总体架构,成功实现了系统的上线运行。应用结果表明:该系统实现了电网重要输变电设备的安全预警,为输变电设备运行管理提供了决策信息支持。     

基于IEC最新标准的继电保护及故障信息处理系统设计

提出了基于通用监控软件平台和最新国际标准IEC61850和IEC61970的继电保护及故障信息处理系统全新设计思路。全面阐述继电保护及故障信息处理系统的组成及各项功能。     

Improved Inspection of Facilities for High‐Voltage Class Using Data Mining

The inspection of power supply facilities can now be conducted with high accuracy using remote monitoring technology. In contrast, it is difficult to install sensors at demand facilities because their scale and installation environment differ among customers. As a result, the demand facilities are inspected at fixed time intervals. In this paper, we propose condition‐based maintenance (CBM), which improves maintenance quality at demand facilities. The proposed method was developed using maintenance data from demand facilities, collected using time‐based maintenance, and we conduct the analysis primarily using failure data. We use data mining to analyze transaction data that we modeled on the basis of the maintenance data and to construct a “failure predictive model” that can predict the failure of facilities and its causes from the results of the analysis. By using the constructed model, we will be able to identify the objects requiring maintenance which may most likely lead to failures in the future, and this study can contribute to improvement of maintenance technologies for demand facilities using the proposed CBM.     

A novel analog maximum power point tracker for low‐cost and low‐power distributed PV systems

The main disadvantage of the voltage‐based maximum power point tracking (VMPPT) method is in the way the photovoltaic (PV) array is disconnected from the load when sampling open‐circuit voltage, which inevitably results in power loss. Another disadvantage is in case of rapid irradiance variation, where the duration between two successive samplings is too long, leading to considerable loss. To overcome these problems, this paper proposes a low‐cost analog VMPPT circuit that is designed on the basis of an ultralow‐power sample‐and‐hold circuit with the least hardware complexity, which has not been reported before. Furthermore, the method of determining the sampling frequency and time interval of the sampling mode is investigated. Experimental verification with a series of different PV power sources is likewise conducted. The experimental results confirm that the proposed MPPT circuit can operate over a wide range of PV power and can adapt quickly to the changing environment. The disconnection energy loss is reduced significantly, with a high system efficiency of up to 95.9%. © 2015 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

110kV大浪智能化变电站备用电源自投装置改造

通过备用电源自投装置功能的了解,以及传统变电站与智能化变电站的通信传输介质差异的分析,提出适应传统的变电站改造为智能化变电站的备用电源自投装置。     

用于船舶综合电力系统同步测量的高精度PTP混合时钟同步方法

为了满足船舶综合电力系统同步测控亚微秒级的精度要求,通过分析各种时钟同步协议的优缺点和传统时钟同步方法对船舶同步测量的局限性,提出一种基于IEEE1588协议的卫星时钟同步与时钟同步频率补偿算法相结合的混合时钟同步方案以实现同步测量。所提方案以环星型拓扑结构的交换式以太网为背景,基于集成IEEE1588协议功能的以太网收发器设计了同步测量节点,并研究了一种频率补偿算法,可以动态地对时钟节点的晶振频率进行补偿,使时钟具有良好的守时性,保证了主从时钟的偏差恒定。通过仿真分析和试验对同步偏差性能进行测试,结果显示同步精度维持在±200 ns以内,达到了IEC61850关于同步测量的标准,满足了船舶综合电力系统时间同步的需要。     

Condition monitoring systems for power equipment using Internet‐based technology

The implementation of Internet technologies in power equipment monitoring systems will allow free and flexible acquisition of power system information and equipment sensor information at remote locations. By utilizing general‐purpose Internet technologies such as IP telecommunication and browser, widely distributed data can be collected easily. This paper introduces the basic configurations of Internet‐based systems and provides examples of where these systems have been implemented. Copyright © 2007 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

A power decoupling control method for an isolated single‐phase AC‐to‐DC converter based on a high‐frequency cycloconverter

This paper proposes a new power decoupling method for a high‐frequency cycloconverter which converts the single‐phase line‐frequency ac input to the high‐frequency ac output directly. The cycloconverter consists of two half‐bridge inverters, two input filter capacitors, and a series‐resonant circuit. The proposed power decoupling method stores the input power ripple at double the line frequency in the filter capacitors. Therefore, the proposed method achieves a unity power factor in ac input and a constant current amplitude in the high‐frequency output without any additional switching device or energy storage element. This paper theoretically discusses the principle and operating performance of the proposed power decoupling method, and the viability is confirmed by using an experimental isolated ac‐to‐dc converter based on the high‐frequency cycloconverter. As a result, the proposed power decoupling method effectively improved the displacement power factor in the line current to more than 0.99 and reduced the output voltage ripple to 4% without any electrolytic capacitor.     

面向状态检修的智能变电站二次设备公共信息模型扩展研究

智能变电站的新特点和新变化对智能站继电保护状态检修提出了新要求,智能变电站二次设备公共信息模型是建设新型智能变电站继电保护状态检修的基础。IEC 61970和IEC 61968公共信息模型(CIM)不能为智能变电站继电保护状态检修提供全面的公共信息模型支撑。基于IEC 61970和IEC 61968的CIM基本扩展原则,通过分析继电保护装置物理结构分层以及智能变电站保护控制系统通过网络化二次回路进行信息交互的新架构,扩展了智能变电站继电保护二次设备资源公共信息模型和继电保护二次设备资产公共信息模型。提出了基于IEC 61850的变电站二次设备状态信息模型到智能变电站继电保护二次设备量测模型的模型映射方案,构建了完整的智能变电站继电保护二次设备公共信息模型架构,为智能变电站继电保护状态检修的应用和二次运维管理系统信息的集成和交互奠定了基础。     

Evaluation of a plug‐in hybrid electric vehicle considering power generation best mix

In the transport section, it is necessary to reduce the amount of CO₂ emissions and oil dependence. Bio fuels and fuel cell vehicle (FCV), electric vehicle (EV) and plug‐in hybrid electric vehicle (PHEV) are expected to reduce CO₂ emissions and oil dependence. We focus on PHEV. PHEV can reduce total energy consumption because of its high efficiency and can run with both oil and electricity. Introduction of PHEV reduces oil consumption, but it also increases electricity demands. Therefore, we must evaluate PHEV's CO₂ reduction potential, not only in the transport section but also in the power grid section. To take into account the distribution of the daily travel distance is also very important. All energy charged in the PHEV's battery cannot always be used. That influences the evaluation. We formulate the total model that combines passenger car model and power utility grid model, and we also consider the distribution of the daily travel distance. With this model, we show the battery cost per kWh at which PHEV begins to be introduced and oil dependence in the passenger car section is to be reduced to 80%. We also show PHEV's CO₂ reduction potentials and effects on the power supply system. © 2010 Wiley Periodicals, Inc. Electr Eng Jpn, 171(2): 12–22, 2010; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20920     

A high‐speed reclosing method to improve the stability in a power system

This paper proposes a high‐speed reclosing operating method to improve the stability in a power system. The proposed method calculates the reclosing time, taking a standard case in which the reclosing is not done using the generator phase angle δ, and the angular velocity ω, and the field system voltage ed′. Also, the execution of reclosing time is calculated, while taking into consideration the acceleration/deceleration energy of the generator during a fault. It can be expected that δ is suppressed by this optimum reclosing operation. Therefore, the system stability can be expected to improve by carrying out high‐speed reclosing when a fault occurs. At present, it has been set at a value which seems to be optimal considering various problems in the reclosing time. However, in those methods, the system stability improvement effect cannot be expected. It was demonstrated that the high‐speed reclosing method serves to depress δ in the computer simulation. © 2004 Wiley Periodicals, Inc. Electr Eng Jpn, 147(2): 13–21, 2004; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10317     

沙角C电厂660MW机组动力设备状态检修实施

针对沙角C电厂动力设备检修现状,提出一套完整的状态检修平台设计方案。该检修平台在对动力设备运行数据分类整理的基础上,充分挖掘数据信息,运用模糊数学理论对所有参数进行加权综合评判,得出设备的运行状态;依据设备的运行状态信息,运用模糊识别方法对设备进行故障诊断,得出设备运行的风险评判;运行人员参照设备的风险评判,结合人工现场经验判断,给出动力设备最优的检修策略。在沙角C电厂660 MW机组动力设备的实际运用情况表明,该平台界面友好、维护方便、模型推理可靠,为电厂实现检修优化提供了一种可行的方案。     

An improved power flow for an ill‐conditioned power system with FACTS devices

This paper addresses the issue of the computation techniques for assessing the steady‐state power flows controlled by Flexible AC Transmission Systems (FACTS), which contain variable series compensators (VSC), phase shifters (PS), interphase power controllers (IPC), and unified power flow controllers (UPFC). An improved Newton–Raphson load flow program has been developed based on an analysis of the convergence characteristic of the conventional method. It is shown that the conventional method tends to suffer from ill‐conditioning problem, resulting in shrinkage of the convergence region. Based on examinations of the condition number of the Jacobian, a penalty function method is adopted in order to avoid the ill‐conditioning problem and to guarantee a successful convergence. Although the computational burden is increased about 2 to 3 times, the proposed method considerably extends the region of convergence. The effectiveness of the proposed method is demonstrated through numerical examinations using IEEE 57 and 118 bus systems. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 140(1): 30–37, 2002; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10027     

Reactive power compensation in a multi‐line system under sinusoidal unbalanced conditions

A new generalized reactive power compensation algorithm applicable to a multi‐line system under sinusoidal conditions is reviewed. This method does not require any decomposition of reactive power or non‐active current. It is shown that a realization of the compensator can be obtained by means of a simple connection of reactive elements. Accordingly, it is concluded that to compensate the reactive power is a simple circuit synthesis problem. The algorithm is illustrated by means of examples. Copyright © 2010 John Wiley & Sons, Ltd.     

Series resonant ZCS‐PFM DC‐DC power converter with high‐frequency high‐voltage transformer link for high‐power magnetron drive

This paper presents a single lossless inductive snubber‐assisted ZCS‐PFM series resonant DC‐DC power converter with a high‐frequency high‐voltage transformer link for industrial‐use high‐power magnetron drive. The current flowing through the active power switches rises gradually at a turned‐on transient state with the aid of a single lossless snubber inductor, and ZCS turn‐on commutation based on overlapping current can be achieved via the wide range pulse frequency modulation control scheme. The high‐frequency high‐voltage transformer primary side resonant current always becomes continuous operation mode, by electromagnetic loose coupling design of the high‐frequency high‐voltage transformer and the magnetizing inductance of the high‐frequency high‐voltage transformer. As a result, this high‐voltage power converter circuit for the magnetron can achieve a complete zero current soft switching under the condition of broad width gate voltage signals. Furthermore, this high‐voltage DC‐DC power converter circuit can regulate the output power from zero to full over audible frequency range via the two resonant frequency circuit design. Its operating performances are evaluated and discussed on the basis of the power loss analysis simulation and the experimental results from a practical point of view. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 153(3): 79–87, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20126