配网中性点接地方式的分析及选择

介绍了配网中性点接地方式的现状,分析了中性点不接地、经消弧线圈接地、经自动跟踪补偿消弧线圈接地和经电阻接地的特点,并针对配网建设与改造中的不同情况提出建议。     

故障指示器的技术选型和运行分析

介绍故障指示器的产品分类和技术参数,阐述故障指示器的工作原理、技术判据以及其在故障检测中的应用方法,并结合实际应用情况进行分析。     

电流极线路对三极法接地电阻测量结果的影响

在采用三极法测量大型接地网接地电阻的试验中,电流极和电流极线路的布置方式是整个试验的基础,对测试结果起着决定性作用。对云南某变电站接地电阻进行现场测量试验,结果表明：电流极线路的长度对测试结果有影响,当架空线作为电流极线路时,避雷线有分流作用。     

PCB中防止共阻抗干扰的地线设计

电子电路中,共阻抗干扰对电路的正常工作带来很大影响.在PCB电路设计中,尤其在高频电路的PCB设计中,必须防止地线的共阻抗所带来的影响.通过对共阻抗干扰形式的分析,详细介绍一点接地在电子电路中,特别是在高频电路中对共阻抗干扰的抑制作用,以及采用一点接地防止共阻抗应注意的问题.同时对PCB板内地线布局的主要形式和要求进行了简要阐述.     

关于电器漏电保护装置的讨论

分析了各种漏电保护装置的特性及存在的问题,提出了一种最佳方案。     

The French Curricular Exception and the Troubles of Education and Internationalisation: will it be enough to ‘rearrange the deckchairs’?

The history of education in France, with its inherited link between the Republic and the religion of knowledge, produces a specific form of educational functioning, consubstantial to a tradition of selection and a symptomatic lack of what elsewhere is called a curriculum. While the recent introduction of the 'common grounding of knowledge and skills for the end of Compulsory Education' ('socle commun') in the French Law of 2006 eventually opened the door both to the teaching of 'skills' and to the idea of a curriculum, and potentially created a revolution in powers and knowledge, one can wonder to what extent it was not a drop on a waterproof system. The question is also to see what was the impact of international influences in these developments. In this article, we analyse the reality and the ambiguities over the opening up of French educational policy towards international concerns, both in relation to the reception of PISA in France and to the decisions which led to the common grounding. This analysis allows us to raise key questions about what could be the potential consequences of a possible change of curricular policy.     

对零序有功功率选线方法的探讨

对自动跟踪消弧线圈接地系统进行了仿真研究.结果表明:零序功率震荡和采样误差是造成零序有功功率选线方法不准的两个主要因素.为了减小这两个因素的影响,对零序有功功率选线方法的模型进行了改进,并利用MATLAB软件对改进模型进行了验证.     

智能建筑的电气保护与接地

通过对适合作为智能建筑的供电接地系统及其所应采取的各类接地措施作了较为详尽的说明与分析,对智能建筑应采取的电气保护与接地方法提出了适当的建议·     

矩阵测度在消除中性点接地电力系统铁磁谐振中的应用

唯一稳态消谐法是近年出现的新的消除非线性系统谐振的分析方法.该方法的基本思想是如果非线性系统存在一个非谐振的正常解,并且该系统具有唯一的稳态,则此时对应的条件就是系统不发生谐振的条件.本文首次将这一方法应用于消除中性点接地电力系统的铁磁谐振的分析中,以矩阵测度为工具,得到了相应的消谐条件,为该问题的分析提供了新的方法....     

Problem-based learning supported by semantic techniques

Problem-based learning has been applied over the last three decades to a diverse range of learning environments. In this educational approach, different problems are posed to the learners so that they can develop different solutions while learning about the problem domain. When applied to conceptual modelling, and particularly to Qualitative Reasoning, the solutions to problems are models that represent the behaviour of a dynamic system. The learner's task then is to bridge the gap between their initial model, as their first attempt to represent the system, and the target models that provide solutions to that problem. We propose the use of semantic technologies and resources to help in bridging that gap by providing links to terminology and formal definitions, and matching techniques to allow learners to benefit from existing models.