智能楼宇的电气接地

在建筑物供电设计中,接地系统关系到供电系统的可靠性、安全性。智能化楼宇对接地系统提出了新要求。本文简要介绍几种接地系统     

对联合接地方式的理解

接地对于建筑物、电气设备和人员的安全具有非常重要作用,又会影响通信系统的质量。文章在分析接地的作用及基本接地方式的基础上,研究了联合接地系统的组成。并结合某广电大厦的联合接地系统案例,对联合接地系统的设计和应用进行了探讨。     

火电厂接地系统的设计与分析

简述了火力发电的特点和现况,介绍了火电厂接地系统的种类与接地装置。通过某火电厂接地系统的设计实例,说明了该系统各接地环节的参数设定和敷设方式。对其中关于电缆屏蔽层的接地抗干扰问题进行了深入研究,进行了有针对性的实验和数据分析,为相关研究提供了参考。     

调度员仿真培训系统调试

<正>目前的电网调度员培训仿真系统主要面对省、地调度,是针对大电网中性点直接接地系统(110千伏以上电网)设计开发的,而县级调度的电网是中性点不接地系统(35千伏、10千伏电网),两者有比较大的差别。在余杭电网的调度员培训仿     

厦门夜景改造工程前端片区的设计与实施

厦门夜景改造提升工程前端片区灯光演绎控制系统、灯光远程控制系统、能源管理系统、防雷接地系统的设计与实施。     

防雷接地系统施工质量通病及其控制

分析雷电损害和防雷接地在建筑工程中重要性。对建筑防雷接地系统施工常见质量通病进行分析,提出在施工中做好防雷接地系统质量控制的要点。     

TN-S接地系统

在电力系统中为了工作和安全的需要,常需要将电力系统及其电气设备的某些部分和大地相连接,这就是接地。电力系统的接地形式分为IT,TT和TN等3种方式。对TN接地系统的设计与规定进行说明。     

民用建筑电气的接地与安全

在TN-C-S接地系统中,PE线与中性线在进户处分开后就不能再合并,且中性线绝缘水平应与相线相同。施工中应严格执行规范及设计图纸的要求,避免人身伤亡事故及建筑物火灾事故的发生。     

小电流接地选线装置安装中的常见问题分析

小电流接地系统接地选线功能，在综合自动化变电站中是一项重要的功能。零序互感器应用不当，将使小电流接地系统选线装置无法正常工作，达不到正确选线的目的。本文通过认真分析小电流接地系统选线装置的原理，并结合在工程应用上的许多经验，指出应注意的相关问题并给出正确解决方法。     

小电流接地选线装置安装中的常见问题分析

小电流接地系统接地选线功能,在综合自动化变电站中是一项重要的功能.零序互感器应用不当,将使小电流接地系统选线装置无法正常工作,达不到正确选线的目的.本文通过认真分析小电流接地系统选线装置的原理,并结合在工程应用上的许多经验,指出应注意的相关问题并给出正确解决方法.     

EMC中的两种接地技术

电磁兼容接地设计有单点接地和多点接地2种基本方法,低频电路中要求用单点接地,高频电路中用多点接地,用多点接地设备如果不能通过EFT/B测试,可以尝试单点接地方法。实验证明,对某些高频电路完全可以用单点接地方法满足EMC要求。     

微波站接地设计

主要介绍微波站接地电阻要求和计算 ,以及接地网设计。尤其是对在土壤电阻率高的地方建设的微波站 ,论述为降低其接地网接地电阻所采取的措施     

铜材料在输电线路防雷接地中的应用

针对处于沿海盐碱地质等地区的输电线路接地电阻易受腐蚀的问题,提出采用一种新型镀铜接地装置作为输电线路接地电阻的新方法,并应用于生产实际中。通过分析新材料在接地系统中应用的各项效益指标,并与之前传统的接地电阻进行对比,可知利用镀铜作为接地电阻材料,能有效地减少由于雷击而接地电阻不满足要求造成输电线路跳闸的故障,为电力系统的安全稳定运行提供可靠保障。     

10kV供电系统接地方式分析

结合A企业10kV电力系统的问题，对系统接地方式及设备改造进行比较分析，选择与系统相适应的中性点接地方式及其相关设备，并对应用情况进行了分析。     

The Grounding of a Discipline: Cognition and Instruction in Technology Education

Technology education has long struggled to establish itself as an equal partner in general education and often struggled to gain recognition for the value of its instruction. Frequently technology educators tout the effectiveness of their programs based on anecdotal evidence gathered from their classroom experiences on how their instructional methods empower students to learn. Although technology education originated without any meaningful input from cognitive science research, it appears that technology education instruction methods are remarkably consonant with findings from cognitive science that define good instruction. Specifically, there is considerable accord between how instruction in technology education and cognitively based instructional models such as collaborative learning, socially distributed expertise, design/engineering, and project-based instruction can be connected. The role of the cognitive research findings on instruction could inform a long over-due theoretical grounding of instruction in technology education. The absence of research on learning and instruction in technology education could be attributed to a lack of theoretical grounding in this relatively new field. This paper examines four cognitively based models of instruction and reviews the relationships between research in the cognitive sciences on learning and instruction in technology education. The consonance between the research recommendations from the cognitive sciences and practice in technology education instruction could serve to stimulate debate on the theoretical grounding of an emerging field of study.     

10kV城市电网接地方式探讨

分析了目前１０ ｋＶ城市电网接地系统存在的问题,提出了两种改善１０ ｋＶ电网运行状况的方法,并简要说明了各自的优缺点。     

A model to analyse students’ cooperative idea generation in conceptual design

In this article we focus on the co-creation of ideas. Through the use of concepts from collaborative learning and communication theory we suggest a model that will enable the cooperative nature of creative design tasks to emerge. Four objectives of the model are stated and elaborated on in the paper: that the model should be anchored in previous research; that it should allow for collaborative aspects of creative design to be accounted for; that it should address the mechanisms by which new ideas are generated, embraced and cultivated during actual design; and that it should have a firm theoretical grounding. The model is also exemplified by two test sessions where two student pairs perform a time-constrained design task. We hope that the model can play a role both as an educational tool to be used by students and a teacher in design education, but primarily as a model to analyse students’ cooperative idea generation in conceptual design.     

Static hazards of drum filling. I. Actual incidents and guidelines

To safely fill drums with flammable liquids of low conductivity, bonding and grounding may not always be enough. Static discharges may under certain conditions originate from charged liquid in the drum, unaffected by grounding. The problem is discussed with reference to actual incidents, published Guidelines, and the types of static discharges that may occur.