PLC在风机控制方案改造中的应用

介绍了黄石市科威自控有限公司运用嵌入式PLC芯片组生产的EASY-M0808R-A0404NB PLC在风机控制系统中的改造方案,并给出了部分变频器控制的梯形图程序.     

E 面金属膜片波导滤波器的优化设计

本文利用等效电路的方法求得E面全金属膜片波导滤波器的初始尺寸值 ,经过对此滤波器的特性的分析结果与设计要求的比较对滤波器的尺寸加以调整 ,从而准确、快捷地完成滤波器的综合 ,对于E面金属膜片滤波器的工程设计有很大的帮助。     

工频高压锅炉给水泵变频改造报告

本文着重介绍了四川石化自备电站给水泵变频器改造的应用情况。对高压变频系统作了说明,改造结果表明,采用高压变频器对水厂的供水泵设备进行调速节能改造,具有较高的社会效益和经济效益。     

油田高压电机综合故障诊断技术研究

HSE管理体系中,高压电机的安全运行具有重要的作用。通过振动监测高压电机运行状态的传统方法是采用3个单轴加速度传感器进行数据采集,故障诊断的准确性有待提高。将三轴加速度传感器应用于高压电机轴承的振动分析,实现3个方向的振动数据同时采集,简化了测试方案,提高了测试结果的准确性。分析了电机典型故障与电机电流频谱的对应关系,结合振动分析法对高压电机定、转子电气和机械运行状态进行监测和故障预警,从而保证油田高压电机的安全高效运行。     

企业安全用电的防雷措施

雷击就是严重的自然灾害之一。但就我国而言,过去防雷设计在整个建筑设计中所占的比重很小。电气设计人员不重视,其他专业的设计人员更不重视,但雷击所造成的损失却无法轻视。本文通过分析高压送电线路雷击闪络跳闸产生的原因,在进行线路防雷工作时,提出一些合理的防雷方式,以提高送电线路耐雷水平。     

Cultural predispositions,specific affective feelings,and benefit–risk perceptions: explicating local policy elites’ perceived utility of high voltage power line installations

Policy controversies concerning the prioritized expansion of the National Energy Grid in the U.S. have drawn our attention to examine the variations of benefit–risk perceptions associated with High Voltage Power Line (HVPL) installation among policy elites, a critical conceptual segment of political actors constituting the U.S. energy policy subsystem. From early psychometric studies to more recent explorations of the emotional aspects of risk appraisal, specifying the role of affective feelings in understanding risk judgment has been a subject of much previous research. This paper seeks to advance such an affect-driven approach in an attempt to account for social psychology-based factors by systemically investigating how specific emotions and personally held intrinsic values and beliefs jointly influence individual-level perceptions of HVPL benefits and risks, relying on recent original survey data containing individual responses from 420 anonymous community leaders and key local policy-makers in the state of Arkansas. Building upon previous research rooted in the dual process model of risk judgment and appraisal tendency framework, a particular emphasis is given to identifying the triadic relationship between culturally biased value predispositions, specific emotional dimensions of affect heuristics, and perceptions pertaining to various aspects of HVPL risks and benefits. Through the implementation of the causal mediation analysis, we found that the effect of cultural value predispositions (i.e. egalitarianism, individualism, hierarchism, and fatalism) on perceived benefits and risks associated with HPVL installation among policy elites is partially mediated by specific affective feelings (i.e. fear, anger, happiness, and excitement) in very distinct ways. We conclude this paper by suggesting that a more robust understanding of the cognitive mechanism of benefit–risk perceptions, particularly those of individuals with more opportunities and resources to shape related policies, promises valuable insight for the development of more effective risk communications and better policy-making practices.     

三相并网逆变器LCL滤波器的简明设计

LCL滤波器以其较好的滤波性能被广泛地用于并网逆变器,但无阻尼时系统产生谐振,给系统的稳定性控制带来困难。文中在建立三相并网逆变器数学模型的基础上,采用基于d,q同步旋转坐标系的电网电压定向控制策略,利用被动阻尼抑制谐振提高了并网逆变器的稳定性能。文中给出了被动阻尼LCL滤波器的详细设计方法,并比较其与单L滤波器的滤波效果,运用Matlab/simulink建立系统模型并进行仿真,实现了单位功率因数并网。     

压力管道结构及稳定计算

文章对某水电站引水系统的压力管道进行结构及稳定计算,得出高压主管、高压支管及岔管的壁厚。     

引风机高压变频器改造研究

为减少故障和检修时间,延长锅炉引风机电机使用寿命,河北灵达环保电厂对锅炉引风机高压变频进行改造。介绍了高压变频改造的必要性和实施方案,阐述了高压变频改造后的效果,对类似情况下的高压变频器具有指导意义。     

浅谈由变频器控制的电动机正、反转控制的电路设计

由变频器控制的电力拖动系统中电路的设计方法举例,并通过该方法的使用来解决变频器控制的简单的电气控制线路的设计。