Query Methods of Electric Power System

Zou Haokai　Wu Xusheng

【Abstract】With the development of electric power network， the quantities and styles of power equipment also increase at every time. It is very important to achieve the information in the power system of the equipment operation fast and effectively. This article summarizes three current commonly methods for power system then analyses the advantages， disadvantages and discusses the application territory respectively.

【Key word】electricsystem intelligentquery equipment power supply relationship

1 Introduction

The Modern Electric Power Network （MEPN） is more and more complex， the quantities and styles power equipment also increase by the time. The current power system， there are many ways to query system platform based on different adopted different query methods. Traditional way of query such as query system based on C/S mode， there are also with the development of the Internet and widely used query system based on WEB. Power network system abroad， there are based on query methods as Motif technique. This article researches on three kinds of query methods to be discussed and analyzed， and discusses their application territory respectively.

2 The currency data bank query system based C/S

2.1 The introduction of C/S method

C/S system is known as the client and the server structure. [1]It is a software system architecture， through it can make full use of the advantages of both ends hardware environment， will distribute the tasks to the Client and Server end， reduce the communication overhead of the system. Currently most application software system is two layer structures in the form of Client/Server.

Client and Server are in often are far apart on two computers， Client program task is the user's request is submitted to the Server program， and will return to the Server process results in the form of a specific display to the user； Server program's mission is to receive the customer the service request， to carry on the corresponding processing， then return the results to the client.

2.2 Analyses of the C/S query system

The C/S system has the advantage that can give full play to the client PC processing capability； a lot of work can be dealt with in the client and then submitted to the server. The corresponding advantages are the client response speed. Advantages in the following two points：

（1） Operation data， application server load is lighter. [3]The simplest of C/S system structure of database application consists of two parts， namely the client application and database server program.

（2）The storage of data management functions more transparent. [4]In database applications， data storage management functions， is by the server program and the client application independent respectively， and usually put those different （whether known or unknown） can't be in violation of the rules of the foreground application， is centralized in the server program， such as the visitor's permissions， Numbers can be repeated， must have the customer to establish such a rule for each order.

But with the rapid development of Internet， mobile office and distributed office is more and more popular， this need our system has expansibility. Disadvantages in：

（1）The client needs to install the proprietary client software. Involves the installation work is first， secondly any computer problems， such as viruses， hardware damage， require installation or maintenance.

（2） The client's operating system in general， there is a limit. May be adapted to the Win98， but cant be used in win2000 or Windows XP.

（3） The inferiority of C/S architecture needs high maintenance costs and investment.

3 The query system based WEB

3.1 The introduction of WEB query system

The structure of B/S （Browser/Server and Browser/Server mode）， is one of the WEB after the rise of the network structure model， a WEB Browser is one of the main client application software.[6] This model unifies the client， will be the core of the system function realization part focus on the server， simplify the development， maintenance and use of the system. The client as long as the installation of a browser， like Netscape Navigator or Internet Explorer， Server install SQL Server， Oracle， MYSQL database， etc. Browser data is produced through the Web Server and database interactions.

3.2 Analyses of the WEB query system

The WEB model uses three layers structure to solve some disadvantage of the traditional C/S mode. Comparing with the C/S， the advantages as the following aspects：

（1） The hardware environment is different. C/S generally set up on a dedicated network， the network environment in the small scale， local area network （LAN） via a dedicated server connection and data exchange between services. B/S based on wide area network； do not need to be a specialized network hardware environment， such as telephone access to the Internet， and the rent equipment information management.

（2） The different security requirements. C/S usually relatively fixed user base， for information security control ability is very strong[7].

（3） The different application architecture. C/S application can pay more attention to process， can the permissions multi-level calibration， the system running speed can be less considered.

4 The currency data bank query system based MOTIF

4.1 The introduction of MOTIF

MOTIF is based on the XT（X Toolkit Intrinsic） on top of a software package that is located in the user model layer. XT is built on the XLIB library， which provides an object-oriented framework， can create reusable and can configure user component Widget.

Therefore， users do not have to use the library function X Window can easily implement a Motif style GUI， XT provides an object oriented， reusable， configuration interface component framework， called widgets. Motif is Widget provides a variety of common interface implementation.

4.2 The analyses of MOTIF query system

Electric power equipment database query system based on MOTIF in the vast majority of electricity network control system， In the design of the whole program is process oriented method using C language.

OSF/Motif is long ago appear technology， but on domestic research Motif information rarely， adaptive ability of different database from one system to transplant this program to another， although the basic framework and 80% of the code do not need to change， but in the reading part of the database still need to customize according to the difference of different database. Because this software is based on the simulation of the system under development， thus allowing for change in the simulation status， but put into use in actual operation of power network system， the artificial modification of these state parameter is safe is not allowed. Power network system equipment database is quite large， the main purpose of this software development， that is， in order to solve the ordinary power network diagram below equipment database query problem not easily， so how to get useful information from a large amount of data is the direction of this software in a major address.

5 The Conclusion

In this paper， the C/S mode， WEB and query system based on the technology of MOTIF to discuss and research， analyzes the principle of three kinds of query methods and their application in actual. It is obvious that they all have advantages and disadvantages in different practice. C/S mode as one of the most traditional methods， while single open， but it can give full play to the client's processing capacity. The client's response speed is fast. Query system based on WEB mode uses the three layers structure is more efficient and reliable. But the JAVA language in its low efficiency when the database connection. The MOTIF of foreign technology applied in most of the electricity network system， but in system transplantation， database need additional customization. But the electric power network database is quite large； giving itself the power equipment is not easy to query adds additional difficulties.

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