【作者】 乔军伟；

【导师】 田远富；

【作者基本信息】 四川大学 ， 电力系统及其自动化， 2005， 硕士

【摘要】 随着水电气表进入千家万户,人工抄表工作也凸现了其方式的局限性。人工抄表需要抄表人员到现场进行抄收,任务繁重且有笔误等不可避免的因素。原来手抄方式的月抄月送已不合时宜,不能满足能源部门的实时监控,而自动抄表可以很好的解决这一点。利用电力线进行自动抄表在最近几年一直是电力及相关部门迫切想要解决的问题。这种方式不仅减少了人工抄表的人力及资金的耗费,也相对有更高的可靠性和实时性。电力线通信(PLC:Power Line Communication)多年的研究处在挣扎的前行状态中,挣扎是因为有许多难点需要解决,前行是因为看好这种通信方式而做了不懈努力。 抄表和电力线通信技术的结合需要利用低压电力线,这个连接千家万户的电能通道如果能够被用来传输通信数据,将会出现大量的能资节省。这是一种“无新线”(No New Wire)技术,不需铺设新的通信线路,节省了架设新线的资金,也省去了人力浪费的麻烦。它只需在表箱里安装一个数据采集器,利用这个采集器将数据发送到低压配电网电力线上传输,在中压变压器低压侧设置集中器收集数据后通过中高压或专线传输到数据处理中心。它只是暂时增加了表件安装的费用,从长线投资来看是值得的并且其用途有很大的拓展空间。 然而低压电力线通信应用并非一帆风顺。相对于我国低压电力线通信信道远较欧美差的特性,电力及相关部门的高要求显得操之过急。高速率和高实时性与高可靠性是相矛盾的,国内许多研究用欧美等相关芯片改造以迎合这一要求,多有试点,而成功很少。在突破这一常规,实行超窄带等低速抄表方案却取得阶段性成果。更多还原

【Abstract】 Along with the entrance of more kinds of meters into more families, the limitations of the pattern of Manual Meter Reading (MMR) was more and more obvious. MMR not only needs workers to go to the sites to read meters, but also this pattern becomes more burdensome and mistakes which can’t be avoided. The former MMR has been outdated. It can’t meet the needs of the energy department’s real-time supervision while Automatic Meter Reading(AMR) can perfectly solve the problem. So in recent years, how to use the technology of AMR through power line is the problem that power and the relative departments urgently want to solve. AMR not only decreases the costs of labor and money in MMR, but also is more reliable and real-time. The research on Power Line Communication (PLC) has been staggeringly going ahead for many years, as many problems still wait to be solved though many efforts have been made in this aspect.The use of low-voltage power line is quite necessary to unite the technology of meter reading and PLC. If the power channel that connects numerous households can be used for data transmission, large quantities of resources can be spared. AMR is a kind of No New Line technology, which need not erect new communication line and can save the corresponding funds and manpower. AMR only needs to install a data collector in meter box. This collector is used to transmit data through low-voltage power distribution network. A gather meter is also necessary beside the low-voltage of middle-voltage transformer to gather the data transmitted from collectors and then transfer the data to data process center through middle-voltage power line or special communication line. It will increase the costs of meter installation in short term. Butin long term it is well worth investing for the large space of its development in usage.However, the process of application of PLC on low-voltage line is not so smooth. The high request of power and the relative departments seems too haste to set high standards as the channel character of low-voltage PLC in China is not so satisfactory when compared with that in Europe and America. High speed and being highly real-time is contradictory to high reliability. To meet such requirements, European and American relative chips are adopted in many researches in China. Though many experiments have been made in this aspect, few make any success. However, phase achievements have been made in low speed meter reading scheme such as using Ultra Narrow Band (UNB) without the bondage of that rule.So a new remedy is suggested in this paper. Phase Shift Keying (PSK) is used in this paper which constitutes Narrow Band PLC (NB-PLC) from the perspective of using frequency band. Comparing the three basic modulation patterns, PSK is the same as ASK and higher than FSK at frequency band utilization ratio, while PSK has the lowest BER at anti-interference which is even better than Spread Spectrum Carrier (SSC) when it runs at low speed. Meter reading through power line requires strong abilities of anti-interference and high reliability. The adoption of PSK is more suitable for the condition of frequency band shortage, high relative speed and heavy interference outside. And PSK can be easily realized and designed with low cost thus decreases the high costs of present AMR design.This system is designed to meet the requirements of being economic, high reliability of power line transmission, and low real-time. This paper first analyzes the low-voltage power line channel character, and then make a comparison between the BERs of several kinds of modulation technologies and expounds the feasibility, advantages and practicability of using PSK technique for the modulation plan of PLC in details. Subsequently, the design of hardware and software are detailedly discussed. Finally, the system debug and performance analysis are also listed in the paper.更多还原