外文翻译-区域电能质量监测系统的设计与实现

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 ofcommunication 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 powe

4、r 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 netwo

5、rk 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 monito

6、ring 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 st

7、andard 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 monitoring

8、. 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 PQDIFThe storage data of the regional power quality monitoring system has the characteristic of multiple attribute, sharing, multip

9、licity 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 QualityData Interchange Format）.The standard of PQDIF is de

10、fined 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 PQDIF, ea

11、ch 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 compact.

12、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 readingprogram of PQDIF get the whole structure fast and doesnt need to decode all contents of file.Therefore, good versat

13、ility, 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 basic funct

14、ions 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 monitoring system

15、, 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 PrincipleT

16、he 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

17、problems, which get from the character of sensing devices and dataof monitoring online.“HEN” and ”LSE” express the reason of power quality problems and corresponding countermeasure. If the condition or fact of “F” is met, expert system will execute the result or operation of “THEN”.Expert system ado

18、pts the BPNN (back propagation neural network 2) as the layer network which has the function of study. The BPNNs structure is as follows:Fig.1. structure of BPNNFist of all, as the multiple forward direction network of one-way transmission 5, the input signal of BPNN is transmitted from nodal points

19、 of input layer to nodal points of middle layer in turn. Secondly, the signal is transmitted from nodal points of middle layer to nodal points of output layer. During this process, the output of each layer only effects its next layer. Each nodal point has its own single nerve cell (nonlinear element

20、 of multiple input and single output) and its character of unit is sigmoid. Neural network compounds simple nonlinear function several times to approximate complex function. Its property is guaranteed by theorem of Kolmogorov.The theorem of Kolmogorov provides a continuous function F: UnRm，f（x）=Y. i

21、s the closed interval 0,1. This function is implemented accurately by three layers of neuralnetwork. The first layer of neural network has n units of disposal, middle layer has 2n+1 units of disposal and the third.B. Expert System Design of Basic FunctionAccording to the demand of regional power qua

22、lity monitoring system, the basic function of expert system includes the child system of collecting rules, fault diagnosis, load prediction, electric network dispatching, system controlling and inquiry. The basic block diagram is as Fig.2:Fig.2. basic block diagram of expert systemThe child system o

23、f collecting abstracts the rules of sample datas formation, learns and adjusts these rules through neural network training; the child system of fault diagnosis/ loadprediction/electric network dispatching/ system controlling matches coherent models from knowledge base by some inference rules and exe

24、cutes corresponding controls after making sure the type.; the child system of inquiry adopts two module (inquiry of data and graph) to meet users?demand.C. Expert System Design of StructureThe general structure of expert system includes knowledge base, inference machine, synthetical database, man-ma

25、chine interface, mechanism of explanation and the modules of knowledge collecting. Its input is the wave of disturbance and its output is the fault types combined wave of disturbance and the operation to the relative devices.1) Inference Machine:Inference machine, as the core of expert, which is a g

26、roup of program, controls and coordinates the works of whole expert system. It disposes and figures out current problems by l knowledge from knowledge base and some inference strategy.2) Knowledge Base and its Management System:It is established according to the standard of IEEE about power quality,

27、 sums up from the experience of power quality experts and expresses itself in the form of rules. And as the experience is accumulated, knowledge base can be extended, modified and be held by users.3) Database and its Management System:It stores the original data of regional power quality monitoring

28、system and middle data which is got during the inference process.4) Module of Explanation:It can explain the behavior of expert system, answer the question that users put forward and help system constructor to find the mistakes of knowledge base and inference machine during the process of explanatio

29、n. It is helpful to adjust and maintain the system.5) Module of Knowledge Collecting:It is also a group of rules and it is the framework of collecting knowledge. It transmits the knowledge to the base, protects the compatibility and integrity of the knowledge base and sets up the base of good perfor

30、mance.6) Man-Machine Interface:It is the interface among expert system, experts of power quality area and users. The man- machine interface, which works for input and output, is made up of a group of programand corresponding hardware.Experts of power quality area input knowledge by man-machine inter

31、face and update knowledge base; users obtain the status of regional power quality by this interface; expert system output result of operation by it. Moreover, man-machine interface transforms the form of inside and outside during the process of input and output. CONCLUSIONFrom the long-term interest

32、, the single point power quality monitoring cant meet the demand of the modern electric industry management. Therefore, it is urgent to establish a powerquality monitoring network which is wide covered , reliable and stable.The regional power quality monitoring system this paper puts forward has the

33、 meaning as follows:A. Open DesignIt can analyse and reflect the regional power quality in time. After the regional power quality is analysed, expert system can predominate the inherent law of the index change online and make sure the source of trouble and pollution. It can provide the data gist of

34、the system fault reason; it can help expert system test the rationality of the electric network structure and the parameter configuration; it can promise that the network is stable, safe and economic.B. Regional and SharingThe regional power quality monitoring system makes monitoring change from sin

35、gle point to region. This mode is useful to achieve centralized management and network monitoring and the regional monitoring is convenient for network to share the data. The regional monitoring can carry out the network management in deed.C. Safe ReliabilityThe regional power quality monitoring sys

36、tem can improve safe reliability. On the one hand, it can monitor actual power quality of customers and is useful to establish a green electric power system. On the other hand, it makes the power quality monitoring develop more deeply and widely. In future, the late-model power quality system, such

37、as tendency of fault analysis, maintenance of prescient load, also can be applied for monitoring in our life.中文翻译区域电能质量监测系统的设计与实现1.引言随着电子技术的飞速发展以及各种类型非线性、冲击以及不平衡负载的快速增加，由谐波，三相不平衡电压，电压波动和闪变引起的问题越来越严重。一方面，如果电能质量较差，它会加快绝缘设备的老化，电气设备的效率以及利用率下降还影响通信系统的正常运行。它会产生电能质量体系供消费者利用并帮助建立一个环保的电力系统。存在巨额亏损的风险行业必须要有高质量

38、的电能质量。另一方面，电力作为一种商品，它是由供电公司和发电企业在电力市场机制下独立运作的。在这种环境下，它是开放的并且鼓励竞争，这将会给电能质量带来更高的要求。因此供电的质量将会直接的影响电力供应公司所占有的市场份额。所以，提高电能质量的水平，增大研发力度以及研究新的电力电能技术，而且建立这样一个环保和高质量的电能监测系统是具有相当重要的意义的。本文提供了一个区域电能质量监测系统。它拥有一个覆盖范围广泛，稳定而且可靠的电能质量监测网络。该网络还能够反映和分析出电能质量的整体水平。这个区域电能质量监测系统通过 GPRS 无线网络通信来传输数据，采用PQDIF 的标准以及建立一个包括故障诊断，系

39、统控制，电网调度，负荷预测等的专家系统。这一区域电能质量监测系统对数据信息层进行集中管理和网络监控是很有用的。它可以实现网络数据的共享和监控系统的网络管理，还可以提高电网实时监控的安全可靠性。2.PQDIF 标准区域电能质量监测系统的存储数据具有多重属性，可共享以及多样性等特点。从整体上控制电能质量以及与其他系统一起改善共享数据库，各区域电能质量监测系统采用电能质量数据规范即 PQDIF 的数据规范标准（电能质量数据交换格式）。PQDIF 的标准是通过 IEEE 1159.3 3-4 所定义的，这是一个平面文件的结构，并与一套符合逻辑的纪录紧密相连。PQDIF 的标准包括两个层次：物理层和逻辑

40、层。物理层描述文件的物理结构而逻辑层则是描述的逻辑关系。在 PQDIF 的文件中每个记录都具有相同的结构，包括记录头和记录体。记录头具有独特的识别特征，记录体则是由一套包括收集，标量和矢量的一组基础单元组成。PQDIF 的标准是二进制格式。即使是没有经过压缩，他们也是非常紧凑的。PQDIF 提供了有效的压缩格式 zlib。这种格式只是将记录体压缩至独立的板块之中，记录头并不会被压缩。这种方法使得阅读 PQDIF 的程序的整个结构速度加快，不需要解译出所有文件的内容。因此，PQDIF 的良好的通用性，强大的数据处理和压缩能力非常适合区域电能质量监测系统，因为它为电能质量数据提供了一个通用平台。3.专家系统区域电能质量监测系统不仅含有对电能质量数据的指标分类，统计，分析等基本功能，而且它的专家系统还含有故障诊断，系统控制，电网调度，负荷预测等功能。专家系统是属于区域电能质量监测系统，根据知识和经验的判断和推导，他是电能质量领域的专家所提供的。专家系统可以模拟专家们的决策过程用来对付复杂难解的需要由专家来决定的问题。A：专家系统的设计原理