1、英文原文 Design and realization of regional power quality monitoring system INTRODUCTIONAS the development of the electronic technology and the increase of different type of nonlinear, impact and out-of-balance load, the problem of harmonic wave, unbalance of three-phase voltage, voltage pulsation and f
2、lickering is more and more serious.On the one hand, if power quality is bad, it will speed up the insulation aging of the devices, reduce the efficiency and utilization ratio of electrical devices and effect normal operation of communication system. As a result, it will bring consumers power quality
3、 of the system and help to establish a green electric power system.huge losing to the industry which has the require to the high power quality. On the other hand, power, as a merchandise, is operated independently by electric power supply company and electric power generation at the mechanism of pow
4、er market. This environment, which is open and encourages competition, will bring forward higher request to power quality. The quality of supply power will effect market share of electric power supply company directly.Therefore, it is the active demand to deal with the pollution of the electric netw
5、ork by effective measure, improve the level of the power quality and increase the development and research of new electric power technology. And it is meaningful to constitute a power quality monitoring system which is environmental and high quality. This paper provides a regional power quality moni
6、toring system. It has a power quality monitoring network which is wide coverage area, stable and reliability. The network also can reflect and analyze the whole level of power quality. The regional power quality monitoring system transmits the data by GPRS wireless network communication, adopts the
7、standard of PQDIF and strike up the expert system which includes fault diagnosis, system control, dispatching of electric network, load prediction and so on. This regional power quality monitoring system is useful for data information layer to carry out the centralized management and network monitor
8、ing. It can achieve the network data share and network management of monitoring system. Also it can improve safe reliability of electric network, monitor real. STANDARD OF PQDIF The storage data of the regional power quality monitoring system has the characteristic of multiple attribute, sharing, mu
9、ltiplicity and so on. To control the power quality from the whole and improve the sharing of database with other systems, the regional power quality monitoring system adopts power quality data specification, which is the standard of PQDIF（Power Quality Data Interchange Format）. The standard of PQDIF
10、 is defined by IEEE 1159.33-4, which is a structure of flat file and linked by a set of logical record. The standard of PQDIF includes two layers: physical layer and logical layer. Physical layer describes physical structure of file and logical layer describes logical relationship. In the file of PQ
11、DIF, each record has the same structure including record head and record body. Record head has the unique identification character. Record body is constituted of a set of elements including collection, scalar and vector. The standard of PQDIF is binary format. Even it is not compressed, it is very c
12、ompact. PQDIF provides effective compressed format ZLIB. This format only compresses record body into the independent block. But the record head is not compressed. This method makes the reading program of PQDIF get the whole structure fast and doesnt need to decode all contents of file. Therefore, g
13、ood versatility, stronger data-handling capacity and compressibility of the PQDIF is suitable for the regional power quality monitoring system which this paper puts forward as general purpose platform of power quality data. EXPERT SYSTEMNot only the regional power quality monitoring system has the b
14、asic functions of classifying the index of power quality data, statistic, analyse and so on, but also its expert system has the functions of fault diagnosis, system control, dispatching of electric network, load prediction and so on. The expert system, which belongs to regional power quality monitor
15、ing system, judges and deduces by the knowledge and experience which is provided by the experts of power quality area. And the expert system simulates the decision-making process of experts in order to deal with the complicated problems which need to be decided by experts.A. Expert System Design of
16、PrincipleThe data of regional power quality monitoring system has layer has m units of disposal.its own characteristic. If expert system collects the data of sample, it uses production rule (IF-THEN or IF-THEN-ELSE rule) to express the relation of input and output. “IF” is the characteristic of some sorts of problems, which get from the character of sensing devices and data of monitoring online.“HEN” and ”LSE” express the reaso
