对闭环运行方式配电自动化系统的探讨

通过一个闭环运行的配电自动化系统的实践，简要介绍了一个高科技开发区内配电网自动化的规划功能目标及为实现规划目标对系统变电站、用户变电站、供电线路、通信信道、直流电源、配电网接地方式等方面进行改造的主要内容。在对SuperDMS—2100配电网自动化系统的软硬件结构和功能进行全面介绍和分析的基础上，着重对闭环运行需特殊考虑的问题以及具有故障状态差动保护功能的FTU进行了论述。最后针对闭环运行系统中的中性点接地方式及接地电阻的确定、具有状态差动保护功能的FTU的配置以及闭环运行方式与开环运行方式的结合等几个方面的特殊问题进行了说明，并提出了解决方案。     

闭环运行方式配电网自动化系统的探讨

通过闭环运行配电自动化系统的实践，简要介绍了配电网自动化的规划功能目标及改造的主要内容。在对配电网自动化系统的软硬件结构和功能进行全面介绍和分析的基础上，着重对闭环运行需特殊考虑的问题以及具有故障状态差动保护功能的FTU进行了论述。最后针对闭环运行系统中的特殊问题进行了说明，并提出了解决方案。     

基于配电自动化故障管理的配电网扩展规划方法

针对现阶段配电网规划过程中面临的可靠性问题,提出一种基于配电自动化故障管理的配电网扩展规划方法。首先对配电自动化的故障管理功能进行介绍;其次根据配网公司的盈利性,以其自身利益最大化建立目标函数,决定线路建设、变电站位置和容量,从而提出一种基于配电自动化的配电网扩展规划模型;然后针对所提模型和所研究的规划问题,采用遗传算法对其进行求解,并对配电系统可靠性进行评估;最后,基于仿真算例验证了所提规划模型的有效性。     

基于IEC 61850的配电网数据传输保护机制

随着配电网技术的发展,配电网络的保护问题变得尤为突出,对其保护性能的要求也逐步提高。随着分布式发电的逐步普及、网状拓扑结构的应用以及电力用户消费者需求的不断提高,需要提供更加智能的保护机制。在基于IEC 61850协议的基础上对变电站内通信进行扩展,将其概念扩展到变电站之间的通信,即配电网通信。文章详细介绍了故障通道继电保护和电流差动继电保护两项技术,作为配电网馈线自动化和网络通信保护,并在原有的基础上创新地提出了两种保护技术用于配电网通信保护的保护方案。     

基于IEC 61850的配电自动化数据传输保护机制

随着配电网技术的发展,配电网络的保护问题变得尤为突出,对其保护性能的要求也逐步提高。随着分布式发电的逐步普及、网状拓扑结构的应用以及电力用户消费者需求的不断提高,需要提供更加智能的保护机制。本文在基于IEC 61850协议的基础上对变电站内通信进行扩展,将其概念扩展到变电站之间的通信,即配电网通信。本文详细介绍了故障通道继电保护和电流差动继电保护两项技术,作为配电网馈线自动化和网络通信保护,并在原有的基础上创新地提出了两种保护技术用于配电网通信保护的保护方案。     

广东电网中低压配电网自动化规划研究

为全面提高广东电网各供电局的供电可靠率,提升配电网运行的自动化水平,广东电网组织进行了"十二五"中低压配电网自动化规划.阐述了规划的范围、原则、目标以及方案特点,举例分析了规划的效益,说明该规划具有可行性和可操作性.     

提高农村10kV配电网开关跳闸选择性的新方法

针对农村10 kV配电网线路长、分支多,线路各保护之间以及与变电站出线开关保护配合困难等问题,基于配电网自动化技术,对农村配电网开关跳闸选择性差进行了分析,提出了利用智能开关的来电延时合闸、电流保护、分界相间和自动重合闸功能,提高开关跳闸选择性的新方法,解决了开关保护难以配合的问题。结果表明:新方法不但可准确判断故障点,而且有效提高了农村10 kV配电网开关跳闸的选择性。     

无人值班变电站自动化系统特点及作用

着重介绍了配电网无人值班变电站自动化系统常用结构模式及硬件选取原则,自动化系统设计的要求以及部分特殊信号的处理方法.对无人值班变电站的具体实施提出了几点重要建议.概括了无人值班变电站自动化系统的主要作用.     

配电网分块规划的构思与实施

介绍了浦东新区配电网现状 ,提出了适应浦东配电网发展的“配电网分块”的规划思路。介绍了分块的划分方式 ,分块后的变电站分布、配电网规划的原始资料积累、分块规划方案的实施以及实施进度。“配电网分块规划”的实践经验对国内现代化城市配电网规划工作具有参考价值     

县级城市配网自动化系统的研究和实施

配电自动化是电力自动化新的发展方向,包括变电站自动化、馈线自动化、用户自动化和配电管理自动化等内容。本文介绍县级城市配电网自动化的目的、适用范围、配电网的基本条件和实施配电网自动化的技术问题,同时对实施配网自动化后的社会和经济效益进行了分析。     

On a wing and a prayer

The article talks about recent Defense Research Projects Agency (DARPA) presolicitation notice in the area of hybrid insect micro-electromechanical systems (MEMs). DARPA's goal is to fund promising interdisciplinary research that will permit the creation of "insect-cyborgs"     

Making a Case for a New Connector

The emergence of quick lock connectors, particularly quick lock versions of the SMA and N connectors (QMA and QN, respectively), was an inevitable development in the RF connector industry and is of significant importance in that nearly 50% of all practical applications for RF connectors are currently supported by either SMA or N. Once QMA and QN can achieve similarity in cost and performance to the present SMA and N connectors, they will take the place of their predecessors in most applications, creating a huge new market. Our RF team has long been dedicated to research and development of these two connector types in the hopes of creating an optimal design. In this article, we will show some of the results of our research.     

利用光伏电池给蓄电池充电

磷酸锂铁（LiFePO4）电池对比钻基德Li离子/聚合物电池,具有安全性性高、浮充电压小、自放电率低、使用寿命长等一系列优点。本文所述LT36521C为可实现太阳能跟踪、单块式补偿蓄电池充电的集成电路。当LT3652由单块太阳能电池板供电时,其输入调节回路能确保在最大输出功率下工作,充分体现出这一新型太阳能充电器的优越特性。     

Chaos in a series circuit with a nonlinear capacitor and a nonlinear inductor

This paper proposes a nonlinear circuit that generates chaotic oscillations. The proposed nonlinear circuit includes a nonlinear capacitor and a nonlinear inductor by using Generalized Impedance Converters. Both computational experiments and experiments on real circuits show that the region for chaotic oscillation is very wide, demonstrating that the proposed circuit is effective as a chaos generator. © 2004 Wiley Periodicals, Inc. Electr Eng Jpn, 150(2): 35–42, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10361     

Electric potential near a tip of a local discharge on a conductive film

To develop a propagation model of a local discharge on a wet polluted insulator, the authors have examined characteristics of the local discharge on an electrolytic solution simulating the wet polluted insulator surface. The local discharge was propagated on the solution under the impulse voltage. A shape of a contacting surface between the local discharge and the solution has been already obtained by the authors. By using the contacting surface, an electric potential near a tip of the local discharge on a conductive film of 1 mm in thickness was calculated. Furthermore, the potential was measured with a probe. The calculated values and the measured values of the electric potential agreed well regardless of the propagation length of the local discharge, the width of the conductive film, the resistivity of the conductive film, the peak value of the applied voltage and the applied voltage waveform.     

Power losses in a conducting ring enclosing a conductor with a transient current

Contents In the paper Joule power losses are calculated in a conducting ring enclosing a conductor with a transient current having an alternating component.—Theoretical calculation and numerical computation are worked out basing on a link Bubnov-Galerkin method in its numerical version using the finite elements for the conductor with the Time-Stepping algorithm for the time discretization.—On the basis of numerical computation, graphs of the relative power losses are plotted as a time function.

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Leistungsverluste in einem leitenden Ring, der einen Leiter mit einem instationären Strom umschließt

Übersicht In diesem Beitrag werden die Joulschen Leistungsverluste in einem leitenden Ring berechnet, der einen Leiter umschließt, in dem ein instationärer Strom mit Wechselanteil fließt. Die theoretischen Betrachtungen und numerischen Berechnungen hat man in Anlehnung an die Bubnov-Galerkin-Methode (in ihrer numerischen Variante, die von einen Leiter unter Verwendung der Methode der finiten Elemente realisiert wird) in Verbindung mit einem Schritt-Algorithmus mit der diskretisierten Zeit ausgeführt. Auf der Grundlage numerischer Berechnungen sind Diagramme für die relative Leistung in Abhängigkeit von der Zeit dargestellt.

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List of symbols Symbol Unit Physical parameter - B Wb/m² magnetic induction vector - H A/m magnetic field intensity vector - H, H A/m -component of the magnetic field vector - E V/m electrical field vector - E _r ,E _z V/m components of the electric field - f s^–1 frequency - I A current intensity (r.m.s. value) - L H inductance - P W power losses - P ₀ W power losses for d.c. - R resistance - t sec time - ^–1 m_–1 electric conductivity of the conductor - Hm^–1 magnetic permeability - _ijk m² finite element area - basis function - rad s^–1 pulsation - N _i ,N _j ,N _k function of finite element shape - 3.141593... - region - ² Laplace's operator - r, ,z cylindrical coordinates - ^h region approximating the region - ^e finite element region - M number of discretization points of the region - V number of finite elements - (N–1) number of steps - i, j, k indices of vertices of triangular finite element     

Development of a deceleration control system for a winding machine based on a microcontroller

The development of an automatic deceleration system for a winding machine in a siderurgy factory is presented in this paper. The proposed system controls the speed of a winding machine in order to obtain the optimum stop point in terms of security and fast production. The system is based on a microcontroller and an extremely simple hardware. The system has been tested for two years and results evince a very good mean time between failures.     

When a feature detector becomes a feature generator

The neural network approach is reviewed in the context of studies in the animal and human visual systems. An attempt is made to explain perception, memory, and learning as a feedback loop similar to the one used in the ALOPEX optimization concept. Applications in pattern recognition and image processing are discussed. Experiments using visual evoked potentials in humans are described.     

Extension of a driving-point and a transfer function to a positive real two-port matrix

A solution is presented to the problem, which arises in two-port modelling, of determining a second driving-point function from a given driving-point function and a transfer function. the given functions must have a common denominator and satisfy the necessary positive real (PR) matrix conditions: the driving-point function must be PR and on the imaginary axis the real part of the transfer function must be zero whenever the real part of the driving-point function is zero. By using a partial fraction expansion and determining a required first-order polynomial, a unique second (minimum) driving-point function is obtained. Examples to illustrate the method are worked out.