PDA电力现场校表系统GPRS数据通信可靠性研究

【作者】 范亮琴；

【导师】 孙斌；

【作者基本信息】 浙江大学 ， 电路与系统， 2007， 硕士

【摘要】 现场校表是电力系统中为了保证电表能够正常运行而对现场的电能表进行检定和相关数据采集的过程，是电力部门特别是电力计量部门最重要的任务之一。传统的手工检测、记录的方式已经不能满足需要。随着计算机和无线通信技术的飞速发展以及互联网的普及，利用先进的通信技术为电力计量部门提供更好的服务，对于提高电力现场校表的工作效率和采集数据可靠性是至关重要的。本文针对PDA现场电表校验业务，利用GPRS网络覆盖范围广以及PDA的操作系统WCE的强大功能和可扩展性，设计并实现了以GPRS无线网络作为载体进行PDA至管理中心主站服务器之间的远程无线数据通信子系统。针对GPRS网络中由于大量数据发送时容易产生丢包、错包而导致终端掉线问题，以及由于多个PDA终端进行并发访问而服务器端不能及时响应而导致终端等待时间过长的问题，本文通过设计改进压缩算法对PDA终端上收发的数据进行压缩，以减少PDA终端与服务器的数据交互流量，从而降低丢包、错包的概率；设计实现一种错误恢复机制，当产生掉线时能够重新恢复任务。另外本文根据电力现场校表的网络结构，在服务器端设计分布式的计算系统，并采取负载平衡的策略，一方面可以提高服务器对PDA终端请求任务的响应速度，降低由于多个终端并发连接而服务器无法及时提供服务的概率；另一方面，提高了服务器资源的利用率，充分发挥服务器系统的作用。本文详细介绍了系统整体设计和具体实现，并对系统的性能进行了测试分析，结果表明系统性能良好，可以较好的满足现场校表无线通信服务的要求。更多还原

【Abstract】 In Power sector, Field-Checkout is a process which checks and data mining from the meters in order to ensure the grid working stably, it’s one of most important tasks in the power sector, but the old ways can’t be satisfied the requirements. With computers and wireless communication technology and the rapid development of the popularity of the Internet, the use of advanced communication technology for the power sector to provide a better measurement of service, it’s critical for efficiency and reliability in power sector. This paper refers to the PDA field-checkout service, using the extensive coverage of GPRS network and the powerful and scalability of WCE operation system, designing and implementing a wireless distance communication system to manage data between PDA and servers based on GPRS network. But PDAs will disconnect if there are lost and error package in case of large scale data, and the servers can’t provide service if there are many connections at the same time, this paper designs and implements a data compression algorithm to reduce the PDA terminals and servers interactive data flow, thereby reducing packet loss and packet wrong probability. Design and implement an error recovery mechanism, which recover the task when the connection lost. At the server side, design and implement a distribute system which uses loading balance strategy, it can enhance the response speed, lower probability when a number of terminals and connecting with the server at the same time and they fail to provide timely service ; the other hand, increased server resource utilization, and give full play to the role of the server system. This paper describes the overall system design and realization, the performance of the system shows good performance and it can better meet the requirements of wireless communications services.更多还原