关于110 kV线路重合闸的探讨

重合闸在110 kV线路供电过程中起到了非常重要的作用,它关系着电力系统运行的安全性和可靠性。在重合闸投运前,需要模拟系统的运行情况,事前试验可能存在的重合闸形式,及时发现、排除其中存在的问题,确保重合闸能够正确动作。分析了110 kV线路重合闸的原理、功能,并以某案例分析为基础,简要探讨了对110 kV线路重合闸控制的相关认识。     

电力系统单回线自适应重合闸的研究

为了能够有效的降低电力系统故障造成的损失,现阶段在电力系统之中正在积极的推行重合闸技术,而在实行重合闸技术的时候,首先就要准确的对电力故障是瞬间性还是永久性进行判断,只有在这个基础上才能够保证重合闸技术的良好效果。本文就电力系统之中单回线类型的自适应重合闸技术进行了相应的研究分析。     

保护装置重合闸误动作问题研究

自动重合闸装置是用来实现线路故障跳闸后开关自动重合,提高供电可靠性,当重合闸充电时间与开关储能时间不相匹配时,将造成开关多次重合,会对断路器本体及系统造成严重影响。本文从实际出发分析了LFP-941D保护装置重合闸误动作原因,并引入“虚拟压力接点”实现了断路器弹簧正在储能时,重合闸不能充电,储能完成后重合闸开始充电,有效解决了LFP-941D重合闸误动问题。     

直流牵引供电系统线路检测与自动重合闸的配合

在直流牵引供电系统中,馈线断路器在合闸前及故障跳闸后重合闸前,需经过线路检测回路对线路进行非短路确认后才能合闸.本文阐述了线路检测及其与自动重合闸配合的原理,并介绍了直流牵引馈线的保护配置.根据运营实例,说明了线路检测在馈线保护中的作用,对其在运行中暴露出的整定及与自动重合闸配合问题进行了分析,并提出了解决方案.     

架空输电线路高速自适应单相重合闸技术

提出了基于可变间歇时间控制的高速自适应单相重合闸方案,在简述重合闸物理机理的基础上,设计了一种混合方案进行次级灭弧来提高系统的稳定性。通过对间歇时间变化的适应性来提高重合闸的成功率,利用初始断路器开路后的电压瞬变波形模式推导灭弧时间的均方根值跟踪方法,最后在750 kV架空输电线路系统上进行了多种故障位置的测试。结果表明：所提出的方案可以显著地减少次级电弧的灭弧时间,加速输电系统在瞬态故障条件下重合闸的正常运行,并且基于可变间歇时间控制的自适应单相重合闸方案可以作管理高压输电运行的有效方法。     

模糊控制理论在继电保护领域的可行性研究及其实现

本文简单阐述了继电保护的发展现状,研究了模糊逻辑与模糊模式识别在电力系统继电保护领域重合闸环节中的应用,并且提出了基于模糊综合决策的自动重合闸控制过程及其实现步骤,以提高重合闸的成功率。     

基于模糊神经网络的单相重合闸故障识别

自动重合闸是提高电力系统供电可靠性、保证电力输电线路安全运行的重要装置,广泛应用于供电输送线中。针对自动重合闸电压判据可能出现误判的情况,文章提出了一种将模糊神经网络应用于单相自动重合闸故障识别的方法,构造了一个具有2个输入、1个输出的模糊神经网络模型,用于识别瞬时性故障与永久性故障,并采用从样本中获取模糊规则的方法和利用Matlab软件对该方法进行仿真实验。仿真结果验证了该方法的可行性和准确性。     

110kV电站稳控装置与线路保护装置定值配合案例分析

本文通过一起并列运行双回线其中一回线路瞬时故障保护装置跳闸重合闸动作前稳控装置已动作切机的案例, 分析了110kV 并列运行双回线线路保护装置中距离III段动作时间、重合闸动作时间与110kV电站稳控装置切机动作时间失配的原因,总结了三者之间配合的基本原则;根据电网的实际运行情况,提出通过优化110kV线路保护距离III段动作时间、线路两侧重合闸动作时间来确保与稳控装置动作切机时间配合的解决方案,以避免重复发生线路瞬时故障重合闸动作之前稳控装置先行切机的类似事件,保证了机组发电的连续性及电网供电的可靠性,消除了110kV并列运行双回线线路保护装置与110kV电站稳控装置时间定值失配带来的不良影响。     

重合闸拒动引起开关非全相运行原因分析

分析220kV乐凤线重合闸拒动引起开关非全相运行事故的原因,并提出相应的解决措施。     

一种基于仪控的自动重合闸控温系统设计

阐述了基于仪表与继电接触器而设计的一种实用可行的自动重合闸控温实例,分析了其性能、特点及应用.     

European Community policy and the market

Abstract This paper starts with some reflections on the policy considerations and priorities which are shaping European Commission (EC) research programmes. Then it attempts to position the current projects which seek to capitalise on information and communications technologies for learning in relation to these priorities and the apparent realities of the marketplace. It concludes that while there are grounds to be optimistic about the contribution EC programmes can make to the efficiency and standard of education and training, they are still too technology driven.     

一种自适应子融合集成多分类器方法

融合集成方法已经广泛应用在模式识别领域,然而一些基分类器实时性能稳定性较差,导致多分类器融合性能差,针对上述问题本文提出了一种新的基于多分类器的子融合集成分类器系统。该方法考虑在度量层融合层次之上通过对各类基多分类器进行动态选择,票数最多的类别作为融合系统中对特征向量识别的类别,构成一种新的自适应子融合集成分类器方法。实验表明,该方法比传统的分类器以及分类融合方法识别准确率明显更高,具有更好的鲁棒性。     

煤矿井下安全监控分站的设计及其仿真实现

为了设计一种具有低成本、低功耗、易操作、功能强且可靠性高的煤矿井下安全分站,针对煤矿安全生产实际,文章提出了采用MCS-51系列单片机为核心、具有CAN总线通信接口的煤矿井下安全监控分站的设计方案;首先给出煤矿井下安全监控分站的整体构架设计,然后着重阐述模拟量输入信号处理系统的设计过程,最后说明单片机最小系统及其键盘、显示、报警、通信等各个组成部分的设计;为验证设计方案的可行性与有效性,使用Proteus软件对设计内容进行仿真验证,设计的煤矿井下安全监控分站具有瓦斯、温度等模拟量参数超标报警功能和电机开停、风门开闭等开关量指示功能;仿真结果表明:设计的煤矿井下安全监控分站具有一定的实际应用价值.     

基于QTE的蒙古文显示机制研究与实现

蒙古语言是中国蒙古族使用的通用语言,由于蒙古文区别于其他文字的书写方式和其自身变形机制等特点,在很多通用的文字处理引擎中都不被支持。在嵌入式产品开发与应用领域中Linux加QTE已经成为流行方式。该文给出了一种在QTE环境上实现基于标准Unicode的蒙古文点阵显示和变形算法, 并自定义了支持蒙古文的QTE组件,扩展了QTE功能,为在Linux加QTE方式的嵌入式体系结构中处理蒙古文提供了一种解决方法。     

基于AD9626的模拟信号采集存储卡设计

自然界的绝大部分信号都是以模拟的形式存在,因此模拟信号的采集转换存储在数字时代十分关键。文章讨论了在雷达信号处理领域基于AD9626的AD采集存储卡的设计原理、硬件结构和程序设计与芯片配置等问题,为今后相关领域的研究提供了可参考的方案。     

A human-computer interface for non-computer specialists

The COM teleconferencing system was designed to be easy to use for both beginners and people with much computer experience. A number of design choices in organizing the human-computer interface were considered very carefully. These design problems are not unique for teleconferencing applications, but will appear in many other developments of human-computer interfaces for non-computer specialists. This report discusses naming conventions, menu format, user commands, help facility and the treatment of ‘type ahead’ from the users.     

Explanation and prediction: an architecture for default and abductive reasoning

Although there are many arguments that logic is an appropriate tool for artificial intelligence, there has been a perceived problem with the monotonicity of classical logic. This paper elaborates on the idea that reasoning should be viewed as theory formation where logic tells us the consequences of our assumptions. The two activities of predicting what is expected to be true and explaining observations are considered in a simple theory formation framework. Properties of each activity are discussed, along with a number of proposals as to what should be predicted or accepted as reasonable explanations. An architecture is proposed to combine explanation and prediction into one coherent framework. Algorithms used to implement the system as well as examples from a running implementation are given.     

View-based model-driven architecture for enhancing maintainability of data access services

In modern service-oriented architectures, database access is done by a special type of services, the so-called data access services (DAS). Though, particularly in data-intensive applications, using and developing DAS are very common today, the link between the DAS and their implementation, e.g. a layer of data access objects (DAOs) encapsulating the database queries, still is not sufficiently elaborated, yet. As a result, as the number of DAS grows, finding the desired DAS for reuse and/or associated documentation can become an impossible task. In this paper we focus on bridging this gap between the DAS and their implementation by presenting a view-based, model-driven data access architecture (VMDA) managing models of the DAS, DAOs and database queries in a queryable manner. Our models support tailored views of different stakeholders and are scalable with all types of DAS implementations. In this paper we show that our view-based and model driven architecture approach can enhance software development productivity and maintainability by improving DAS documentation. Moreover, our VMDA opens a wide range of applications such as evaluating DAS usage for DAS performance optimization. Furthermore, we provide tool support and illustrate the applicability of our VMDA in a large-scale case study. Finally, we quantitatively prove that our approach performs with acceptable response times.     

Call for papers Special issue on Modeling and control technologies for civil,energy,and power systems

正The control of civil,energy,and power systems presents significant new challenges for modeling and control theory.The purpose of this special issue is to provide a forum for researchers and practical engineers to discuss the recent advances in modeling and control technology development for civil,energy,and power systems.Prospective authors are invited to submit their original contributions with the focus on theory or applications of modeling,control     

Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and overseas to the world’s scientific circles,especially to stimulate and promote academic exchange between Chinese and foreign scientists everywhere.