摘要
本文通过分析目前变压器的使用及监控现状,提出了远程电量监控模型。变压器电参数可以通过PSTN、CATV、GSM和光纤等载体传输,根据目前我国的现状,指出了利用PSTN进行数据的远程传输的优势。
基于PSTN的远程电量监控系统通过数据采集模块对变压器的电参数进行采集,主机通过“轮循”的方式,依次拨通每一个监测站点,下位机将检测到的数据通过PSTN公用电话网送到上层监控中心的计算机系统进行存储和处理,以提供主管部门的分析和统计之用。该系统具有设备简单、成本低和准确实用的特点,对于目前电力系统的应用价值较高。
本文介绍了计算机通信基础知识和在通信过程中极其重要的设备—MODEM(调制解调器),对MODEM的工作方式和AT命令集作了较为详细的介绍。随后详细地介绍了系统的总体设计思想和具体的实现过程。
在硬件系统设计中,采用了AT89C51单片机作为下位机主控制器,用于连接MODEM和数据采集模块。通过使用MCS51汇编语言编写程序,实现了下位机与MODEM之间的数据传输,同时实现了自动检测负荷,进行拨号报警的功能,其中重点介绍了单片机控制MODEM进行远程数据传输的方法。
阐述了上位机软件的设计与开发,对通信模块、数据管理模块等作了特别的说明。采用微软公司的高级编程语言Visual Basic作为监控系统上位机软件的开发工具。本文通过对VB提供的用于串行通信的MSCOMM控件所提供的各种功能的调用以及对MODEM编程,实现了从数据链路的建立到通过公用电话网对变压器电量数据采集等多项功能。
采用ACCESS数据库作为系统的后台数据库。利用VB对数据库的编程技术实现了系统对获得的数据的读、写、保存等操作要求。而且能完成各种报表的预览和打印功能。
在文章的最后,对本系统进一步开发的内容和方向提出了设想,对监测系统的无线化结构进行了初步探讨。
通过对监控系统的应用可以改变电量监测手段的落后方式,节省了人力、物力,提高了电量管理的自动化水平和工作效率,特别适合相对分散的变压器进行负荷监测、维护和管理工作,具有明显的经济效益和社会效益。
This paper presents a broad review of remote transformer monitoring system by analyzing the present conditions of its application and monitoring mode. We state the availability of the remote electric quantity monitoring pattern.The electric parameters of transformer can be transmitted by all kinds of network and carriers, such as PSTN, CATV,GSM and optical fiber. Combined the current situation of our country, transmitting the data by the PSTN has much more advantage.
The monitoring system of Remote electric quantity Based on PSTN obtains the electrical parameters of transformer by the data acquisition module,host computer dials every monitored station by roll polling.Inferior processor transmits datas to the computer in superior monitoring center through PSTN for storage and processing, to provide the analysis and statistics for the supervisor section . The system is simple and cheap, and it will have a good prospect of application in electrical system.
The fundamental knowledge of the communication is introduced in the paper, followed by the introduction of the Modem, one of the most important devices used in the process of communication.The operation mode and AT commanding is introduced in detail.Then the paper focuses on the integral design idea of the system and concrete realization process.
In hardware system design, we adopted the microcontroller of AT89C51 as the main controller of Inferior processor,it is used to connect the Modem with the data acquisition module.MCS-51 assemble language is used to program the software of the device to realize the data transmission between Modem and Inferior processor.When the electric power in the run is beyond the specified value , the Inferior processor can dial the phone number of central computer automatically to send the alarm message through the communication line.using a single-chip microcomputer to control a modem to transmit remote datas are introduced in detail.
The development of the software of PC are expounded, especially the communication module and the data managing module.Visual Basic is employed as the programming tool for the central computers in the Monitoring System. Through calling various function of the MSComm ActiveX control provided by VB to realize serial-parallel communication and programming the modem.it can realize the function of establishing data link circuit and gathering the electrical parameters of transformer by PSTN and so on .
Access Database is used in this system as backstage Database. VB employs many language commands to access the Database in order to meet the operational demands of reading, writing and saving the data obtained in this system.Moreover, the function of printing and browse is achieved.
Finally, the idea of the system in the further contents and direction approaches are proposed.the wireless structure of the Monitoring System is inquired into preliminarily.
If the Monitoring System is put to use, the old working mode has been changed, the management level and work efficiency has been improved, As a result, personnel and material resources are saved.it is extraordinarily fitted for monitoring load, maintenance and management of relatively scattered transformers, many economic and social benefits have been obtained apparently
引文
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