首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
According to the requirements of communication power supply, such as high reliability, wide application and high availability, the authors raise a new remote control design for a multi-output power supply for communication equipment based on TCPIP protocol and embedded technology. Then the hardware design is given for the system is discussed based on Ethernet professional chip PRTL8019AS and related circuits. The firmware software design for the salve-computer based TCPIP technology, and the soft design of communieation and control for the master-computer are proposed based on Winsoek and MFC technology in detail A test machine is built to do the testing, the test results prove that the test machine works stably and well, satisfies the design rules and also provides a feasible method for the remote supervise in communication power supplier whose requirement includes remote supervise, no-people on duty and so on.  相似文献   

2.
基于3G和VPN的温室远程监控系统的设计与实现   总被引:4,自引:2,他引:2  
根据温室环境的特点提出一种基于3G无线通信技术和VPN(Virtual Private Network)虚拟专网技术的温室远程监控系统。该系统在温室现场设备和中心服务器之间建立无线的虚拟专网,采用Linux操作系统、ARM9处理器作为软硬件平台,能够对温室环境因子数据的进行自动采集、远程传输、存储管理、网络发布、分析处理,同时实现对温室辅助控制设备的远程控制。试验结果表明:该系统设计方案合理、可靠,能满足各种环境因子的数据采集及多种温室辅助设备的远程控制。鉴于设计方案中采用了通用型技术构架,本系统已经扩展应用于其他农业领域中,如农情监测、气象灾害监测预警等,应用前景非常广阔。  相似文献   

3.
A new approach based on sensitivity method for the optimal power flow is presented in the paper. This method has the following advantages: it is suitable to solve a 200-node power system on the microcomputer; the convergence is easy to reach and the computation speed is quick; it is possible to reduce 8-14% power loss and to get maximum economic benefit by using this method; in power system dispatch center it can be used as an on-line voltage and reactive power control program to keep good voltage level. The proposed method has been proved successful by IEEE 118-node test system and the several real power systems such as 49-node, 61-node, 99-node and 200-node systems.  相似文献   

4.
Because of unsatisfied relaying protection of short transmission lines, a new differential protection system consisting of microcomputer and optical fiber channel has been presented in this paper. According to this system, a new algorithm including a differential criterion used for the positive sequence currents caused by faults and a difference-half cycle Fourier filtering method has been set up.  相似文献   

5.
孙瑞  赵杰  卢岳俊 《保鲜与加工》2018,18(2):125-129
针对电商快速发展导致物流交易量增加,从而给仓库存储带来较高成本的问题,提出了一种基于ZigBee技术的物流仓库温湿度监控系统设计。本文结合快速发展的无线传感器网络技术,对物流仓库的温度和湿度状态进行监测,并通过ZigBee技术将传感器数据传输至汇聚节点和嵌入式网关设备,并由嵌入式网关设备将数据转发至监控中心,同时监控中心可以根据仓库状态自动开启相关控温和控湿设备。经实际运行验证,本系统可以实现数据自动化采集、传输和显示温湿度,所设计的系统可以有效提升物流企业的仓库状态监控效率,达到智能化管理要求。  相似文献   

6.
This paper summarizes two kinds of fault detection techniques for distribution automation, that is with and without communication in fault detection, and then analyzes their merits and shortcomings. Moreover, according to the development tendency of distribution automation techniques, this paper presents an approach, through which the noncommunication FTU devices can detect transient fault voltage of distribution systems effectually. To detect transient fault voltage without standby batteries, the PIC Single Chip microcomputer with low power consumption and DSP chip with powerful data processing capabilities are adopted to form a dual CPU system. To realize the communication between the two CPUs, the general I/O port,s of the DSP chip are firstly used to simulate the UART communication of the serial ports and communicate with the PIC Single Chip microcomputer. The novel FTU devices based on this approach are tested in static and dynamic simulation experiments, the results are satisfied.  相似文献   

7.
针对内蒙古自治区生态观测需求,特别是草地生态系统观测需求,选取牧草观测为研究内容,提出基于嵌入式技术和并行计算技术的实时远程可控可视的牧草观测自动化技术思路。采用特征像素图像识别方法,实现牧草覆盖度的自动测量、牧草的发育期图像自动识别。利用摄影测量技术结合图像处理技术获得像高转物高变换算法,实现层高与株高的自动测量。结合现代电子技术以及DSP技术、图像处理技术设计了牧草自动观测智能传感器,传感器在观测前端完成图像采集、处理与模式识别后,再将处理后的结果通过网络传向服务器端,可通过智能手机或PC访问服务器远程查看观测数据,实现牧草覆盖度、层(株)高以及牧草生长期的自动观测。测试结果表明,图像处理与实测覆盖度数值显著相关检验R0.05>0.90,与实测株高数值显著相关检验R0.05>0.85。相对于在后端PC系统进行图像处理,不但可以提高观测系统的数据运算处理速度,而且鲁棒性好,同时能够大大减轻数据传输压力,适合对体积、功耗、工作环境及稳定性要求极高的场合。  相似文献   

8.
In this paper, a new microcomputer distance protection scheme with high property-cost ratio has been approached. The paper presents the performance equations based on the symmetrical components of current and voltage, proposes a new (1,a) coordinate plane and derives a Fourier symmetrical component algorithem with high accuracy and less calculation amount on the (1,a) plane. The protection program is debugged on the developing system of single chip computer. The digital imitation tests indicate that the proposed relaying system is satisfactory.  相似文献   

9.
Considering the interference introduced by primary user, the outage probability of cognitive relay networks under imperfect channel state information is analyzed based, on the relay selection for the maximum channel gain. In addition, the mathematical optimization model of maximizing the spectrum efficiency under the interference constraint of primary user and the QoS requirement of cognitive user is proposed for cognitive relay networks. Then, the optimal solution of the model is obtained with the Lagrangian method. The proposed scheme improves the spectrum efficiency of cognitive relay networks on the premise of guaranteeing the transmission performance of primary user. Simulation results show that the proposed power allocation scheme improves the system performance compared with the traditional equal power allocation scheme. Meanwhile, it indicates that the approximate spectrum efficiency can be obtained under the perfect channel state and the imperfect channel state. Under the imperfect channel state, the feedback information and the complexity of implementation will be reduced, which is beneficial to the engineering application.  相似文献   

10.
This paper introduces the portable data acquisition system based on MSP430F149 micro controller. In this system, PGA chip MCP6s28 is applied to reduce the quantity of devices and power dissipation of the system. Real-time transmission is implemented by the wireless data transceiver. Large memory capacity make it convenient for field operation. The system realizes the menu management by using the graphic LCD. It has the features of small size,low power dissipation, high conversion rate.Therefore,the system is suitable to use dry battery and work in confined space.  相似文献   

11.
To solve the problem that the existing method of extracting fault components is easily affected by power system swing,a new methed has been proposed in this paper,which can be used in high speed protection of transmission lines. This proped method ean greatly decrease unbal-ance outputs under power swing condilions without frequency tracking circuits,therefore it can make the protection using fault compnents operate correctly.  相似文献   

12.
In accordance with the characteristic of digital relay and fault locatoin four methods of phase selection on fault component are presented in this paper.These methods are simple in principle, reliable in action, and immune from load flow,system oscillation.Hardly affected by fault location, source impedance and fault resistance, they can select fault phase reliably for any power system and fault type.As phase selection schemes, they can be used for perfect digital relay.  相似文献   

13.
This paper presents a method which can accurately calculate the fault voltages and currents of the transposed and untransposed transmission lines.It can be applied to the simulation of protection relay analysis and fault location and so on.The principle of method is clear,the computational precision is high and usage is simple.  相似文献   

14.
In view of the actuality of the feeding oil pum monitoring,the network technology,the database technology and the Dot Net remote technology are integrated nimbly to construct the remote condition monitoring system for feeding oil pump,which has many functions such as the real-time data monitoring and alarm,real-time monitor data storage remote monitoring,network data sharing,fault analysis,and so on.The whole construction design of the system and the realization of its sub function are given.The worker's intensity of labor,the maintenance cost and the accident occurrence rate of the feeding oil pum were dramatically reduced when the system was applied to the oil storeroom successfully.  相似文献   

15.
农产品远程价格信息采集和发布系统的研究   总被引:1,自引:0,他引:1  
利用TC35与低功耗单片机结合设计便携式手持数据采集终端,采用手持信息采集终端收集信息,通过GSM方式传送到数据中心,数据中心负责处理和发布信息,实现了农产品远程价格信息的采集和发布,用户可通过上网或手机短信进行价格查询。系统实时性好,可靠性高,克服了以往信息采集发布的缺点,能够有效的进行农产品价格信息方面的信息传递工作及数据统计。详细阐述了手机模块TC35中SMS功能的工作原理、便携式手持终端的硬件设计与软件实现。经示范应用,系统达到了设计目标。  相似文献   

16.
Considering traditional current protection cannot satisfy the micro-grid, a system protection solution for the micro-grid is proposed. In this solution, the failure message with direction information can be exchanged among the adjacent protection units, so the fault coverage can be determined and the fault can be quickly cleared. By analyzing the movement of the protection in three kinds of fault conditions in the micro-grid that contains three branches and two micro-power based on inverter, the method has been proved that the fault can be quickly cleared and the protection has the same protection strategies for both islanded and grid-connected operation.  相似文献   

17.
With the abundance and development ,the transmission of virtual instrument on Internet become the exigent need in the field of instrument .The paper summarizes the building method of running flat to the stream of virtual instrument .The authors can complete remote test,exchange the testing data,so much as establish a dynamic league for test mission through the flat . For this flat ,they bring forward own opinion of systemic framework and running environment as well as local area network building . Furthermore, the anthors set forth the realization of function of accessing to database of virtual instrument.,the layout of site homepage. Finally,they introduce how to configure the site server ,what operating system to be selected for the site server and how to deploy the whole site .  相似文献   

18.
This paper develops a vehicle carried remote data acquisition terminal based on GPS/GPRS integrated DTU(data transfer unit) and CAN Bus data acquisition module, and built a parameter remote monitoring system of HEV with GPRS and Internet. By using PIC18F4580 with built in CAN control module and industrial DTU MD610G, we transmitted the parameter data and GPS information of the HEV(Hybrid Electric Vehicle) terminals to the remote data control center through GPRS(General Packet Radio Service) and INTERNET. Taking VC++ as the development tool, we programmed a monitoring software of data exchanging, data processing and monitoring. The software also has the function of CANoe data playbacking and strengthened the system versatility. Eventually, the parameter remote monitoring system of HEV is developed. The experiment results show that the system works well.  相似文献   

19.
基于科学知识图谱的方法与知识可视化的理论,以CNKI数据库中收录的1997—2016 年20 年间遥感在农业领域研究的文献数据为切入点,探索20 年来遥感在农业领域研究的热点和趋势。通过对具体的机构合作图谱、聚类图谱和关键词图谱进行分析解读,直观展现了该领域正处于快速发展阶段,研究机构差异显著、热点主题明确。通过机构合作分析发现遥感在农业领域研究中中国科学院的发文量居于首位;通过关键词共现分析,探究该领域的研究热点集中在农用地变化和遥感监测以及精准农业形成的3 个大的聚类;最后通过突现检测分析得出,遥感技术和地理信息系统技术在土地利用、核农学和生物科学等领域的运用将成为很长一段时间的发展趋势。  相似文献   

20.
Aiming at the lack of the current determination method for voids in practical engineering applications, in order to accurately quantify the voids beneath cement slab, the determination method was proposed with slab edge slab center deflection difference and slab corner slab center deflection difference in the same cement slab for voids.Three dimensional models were set up using the ANSYS finite element method for voids beneath slab corner and slab edge.And the load was simulated with FWD test results.Thereafter, the deflection values were calculated in slab center, slab corner, slab edge under different void depth, void area and load transfer capacity.And the range of deflection diffidence was obtained.With Yantai Weihai expressway, detection data for deflection using Falling Weight Deflectometer were statistically analyzed.And the criteria and correction factors of load transfer capacity were given with simulation and samples analysis.The feasibility of criteria was verified by actual test data.It is found that the simulation values and the test values are in good agreement.The accuracy of void determination by lab edge slab center deflection difference and slab corner slab center deflection difference are 88.5% and 84.6%, respectively, which meet the engineering requirements.The voids were determined under the same conditions with the elimination of deflection variability.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号