Academic Open Internet Journal

www.acadjournal.com

Volume 14, 2005

 

 

WEB BASED MONITORING OF ELECTRIC POWER DISTRIBUTION NETWORKS

Dr. R. P. Gupta

Department of Electrical Engineering

Indian Institute of Technology Kanpur

Kanpur, Uttar Pradesh – 208 016, INDIA

Email: rampg@iitk.ac.in

 

and

 

Dr. R. K. Varma

Department of Electrical and Computer Engg.

University of Western Ontario

London, Ontario – N6A 5B9, CANADA

Email: rkvarma@uwo.ca

 

 

ABSTRACT: A Web based system has been designed and developed for remote monitoring of electric power distribution network. The developed system is based on three-tier architecture and enables to manage the distribution network through a computer connected on the Internet / Intranet. Under this development, the real time database, which is a part of practical Distribution Automation system, has been converted into commercial database. Further, the data from commercial database is published over the Web using Internet technology. Consequently, the recent and past information of power distribution network is available to electric utility for the purpose of network monitoring and its better planning.

Index Terms: Web Application, Power Distribution Automation, Computer aided Monitoring and Control.

1.  INTRODUCTION

Today, almost every country is going for restructuring of the power system. The concept of restructuring and deregulation of power system assumes the availability of both the system operating point and historical information, almost at every minute. Therefore, online system information is a prerequisite for restructuring of power system. This implies that there is a need to create a centralized database for the power system which is subjected to continuous up gradation [1,2]. Also this would facilitate researchers and experts to find solution for various bottlenecks in the system. Often system analysis and appropriate solution to prevent system failure in future is difficult due to poor access of system data. In this context, centralized database will bring transparency in analyzing the problems and finding the appropriate solution. The various aspects of data repository are data collection, data validation, authentication and updating, method of reporting and necessary backup, data storage and sharing the data among users through the Web [3-5]. It seems that the resent development of Information Technology (IT) may play a leading role to build a power system information grid. In view of the above, objective of this paper is to design and develop a Web based monitoring of power distribution system.

2.  MONITORING STRATEGY

It is well known that Distribution Automation (DA) system enables electric utility to remotely monitor and control the distribution components such as transformers and feeders in real time. The location, from where control action is initiated, is called Distribution Control Center (DCC). The one major task of distribution automation is to retrieve the system information, transmit it to control center and store them in the real time database. Generally the real time database exists at the control center as a proprietary database or in the form of file system in order to reduce the data access time. Recently, distribution automation has been conceptualized and various components of distribution automation has been indigenously developed and implemented in power distribution network of Indian Institute of Technology Kanpur, India [6]. The developed DA system provides system information at every minute on the control center. These system information is stored in a file after every minute automatically. This is shown in Fig. 1. Now, the core objective of this paper is to publish recent system information from flat file system to World Wide Web (WWW). This has been successfully achieved using three tier architecture. The major tasks in this research work have been following.

1-     Design of database in terms of data tables and their relations.

2-     Transacting the data from file system to commercial Relational Database Management System (RDBMS) through a software module, which is named as data transfer program.

3-     Design and development of application logics to interact with clients.

4-     Architecture for data publishing on Web.

 

 

 

 

 

 

 

 

 

 

 

 

 


Fig. 1  Architecture of Web-based monitoring of power distribution system

 

2.1  Database design

A comprehensive database design has been carried out. This includes detailed data analysis, preparation of a design specifications, database programming, database testing and validation. SQL server 2000 has been chosen to build the database for system monitoring. This is a commercial Relational Database Management System (RDBMS). A set of tables along with their columns’ title and data type have been designed. Separate table is made for each of the following data.

a)     Bus Data

b)     Power Source Data

c)      Load Data

d)     Line Data

e)     Line From End Measured Data

f)        Line To End Measured Data

g)     Transformer Data

h)      Transformer LT Side Measured Data

i)        Transformer HT Side Measured Data

j)        Shunt Capacitor Data

k)      Bus Coupler Data

l)        Switch Data

The various issues such as data redundancy and inconsistency, accessing data, data isolation, integrity problems, concurrent access of data and security problems have been addressed during database design. The designed database provides accessibility through Open Database Connectivity (ODBC) interface.

2.2  Data transfer program

Data transfer program aims to read the data from the real time data file, do necessary data processing and then to store these data into standard database (MS SQL server 2000). Real time data file system is organized in many blocks of data. Each block of data begins with an indicator ‘start’ and ends with an indicator ‘end of data’. These blocks cover data for bus, power source, load, line, transformer, shunt capacitor, bus coupler, switch (such as CB, LBS). For an example, a block of bus data is show in Table-1.

 

Table-1  Bus data

Bus No:

Bus Name

Va (kV)

Vb (kV)

Vc (kV)

Voltage Rating (kV)

15

M11BUS2

6.59

6.45

6.39

11.0

12

1_.4BUS1

0.239

0.240

0.238

0.415

18

4_.4BUS3

0.236

0.242

0.237

0.415

28

NW.4BUS1

0.240

0.239

0.238

0.415

36

1_.4BUS2

0.238

0.239

0.241

0.415

 

A data transfer program has been designed and developed according to flow chart shown in Fig. 2. Initially each block of data is read from the real time data file. Then an appropriate Structural Query Language (SQL) string is made and triggered to write a block of data in the standard database ‘SQL Server 2000’. As a result, database server organizes these data in the tables which are already designed. The whole process is repeated after a predefined time interval.

A data transfer program is designed as a set of functions and these functions have been developed using standard ‘C’ programming language. The list of such functions are given below.

a)       void bus_parser ()

b)       void power_parser ()

c)       void load_parser ()

d)       void line_parser ()

e)       void linef_parser ()

f)         void linet_parser ()

g)       void transformer_parser ()

h)       void transformerHT_parser ()

i)         void transformerLT_parser ()     

j)         void shunt_parser ()

k)       void buscoupler_parser ()

l)         void switch_parser ()

 

 

 

 

 

 

 

 

 

 

 


Fig. 2  Flow chart of data transfer program

 

2.3  Application logic program

Application logic program receives request from clients for data, retrieves the relevant data from standard database and sends these data to the appropriate client. Application logic program resides on the server side. This program has been designed and developed using ASP technology. ASP stands for Active Server Pages and it is an advanced form of HTML. ASP technology enables to make the dynamic and interactive web pages. It uses server-side scripting to dynamically produce web pages that are not effected by the type of browser. The default scripting language used for ASP is VBscript (Visual Basic script). Other scripting languages can also be used like Jscript (JAVA script). ASP pages have the extension “*.asp” instead of “*.htm”, which is in HTML page. When a page is requested by a browser by selecting and clicking a specific hyperlink, the web server interpret ASP content within the web page before sending the HTML stuff to the browser. This way all the ASP scripts are run on the web server and no ASP scripts will ever be passed to the web browser. It is to be noted that any web pages containing ASP scripts cannot be run by just simply opening the page in a web browser. ASP allows to use the capability of a web server to process user requests and to provide dynamic data.

Application logic program works according to the flow chart as shown in Fig. 3. When client requests for system data through Web browser, an appropriate ASP script page is triggered to run at server side. The logic embedded in the ASP script collects the required data from database server and present it to the appropriate client on the web. Application logic program updates information every minute at the clients Web browser.

 

 

 

 

 

 

 

 

 

 

 

 

 

 


Fig. 3  Flow chart of application logic program

 

2.4  Architecture for data publishing

A three tier architecture, as depicted in Fig. 4, has been chosen for monitoring of system using Internet technology. This architecture provides greater application scalability, high flexibility, high efficiency, lower maintenance, and reusability of components. In this design, each tier can be run either on a separate machine or on the single machine. It improves system processing performance. These tiers do not necessarily communicate to physical locations on different computers or networks. A typical three layer architecture is divided into following layers.

1. Presentation tier

2. Application tier

3. Data tier

 

 

 

 

 

 

 

 

 

 

 

 

 

 


Fig. 4 Three-tier architecture

 

Presentation tier

This tier enables user to interact with the database through the web browser in a user friendly manner from remote location. It is also called user services layer. It provides user to access the application. This layer optionally permits to feed and manipulate data.

Application tier

Application tier consists of web server and application logic for data monitoring. This tier is also called application service layer. The logics and rules are separately stored in the files using Web scripts. These logics and rules are properly interfaced with the main Web server in this tier. In the current development of monitoring system, Internet Information Server (IIS) has been used as Web server. This provides management services that are shared by multiple applications.

Data tier

This tier is also called data service layer. It concerns with persistent data usually stored in a database or in permanent storage. This is the actual RDBMS access layer. It can be accessed either through the application services layer or on event created by the user services layer.

The major benefits of three tier architecture are reusability, flexibility, manageability, maintainability, and scalability.

3.  TESTING AND RESULTS

Software testing is very important step to maintain the quality of software. The objective behind testing is to detect and fix the errors introduced in different phases of software development cycle. A set of test cases have been designed for this purpose. Some of these are described here.

1.      A set of transformer, feeders and circuit breakers are selected separately to check their heath and related operational data through the web browser. It is observed that the different operational and health parameters are easily available in different dialog box as specified in the “Software Requirement Specification” document (SRS). The SRS has been initially laid down to document the detailed requirement. A window showing the operational and health data for a particular transformer is shown in Fig. 5.

This test verifies proper functioning of the program developed for data transfer as mentioned earlier in the paper and application logics, which have been developed using ASP scripts on the Web server side.

 

 

 

 

 

 

 

 

 

 

 

 


Fig. 5  Window for operational and health data of a transformer

 

2.      To check the concurrency in the developed system, five clients are connected simultaneously with the Web server through the Internet browser. Various parts of distribution system have been monitored simultaneously on these client machines. This shows that distribution system components could be monitored concurrently from multiple clients through Internet browser.

3.      It has also been observed that historical data regarding system operation and an event are easily available with time and date stamps. This verifies the data recording feature of the developed system.

4.      The developed system provides system reports (daily load curve of transformers and feeders) both in tabular and graphical form. This verifies the customized report generation feature.

4.  CONCLUSION

An effort has been made to integrate the DA system with Internet/Intranet system. For this, two separate software have been developed. These are

(1)   Data transfer program

(2)   Application logic program

The former has been written in C language and later one uses ASP technology with Visual Basic and Java scripts. After developing these software, a Web base monitoring for power distribution system has been implemented using 3-tier Internet architecture. The application tier has been realized through Internet Information Server (IIS) and data tier through MS SQL Server 2000. Then after, a set of test cases have designed and carried out for system monitoring. The test results demonstrates proper functioning of developed software components and idea of Web based monitoring of power distribution system.

5.  ACKNOWLEDGEMENT

The authors would like to thank Ministry of Human Resource and Development, Government of India for their support in carrying out this research work.

6.  REFERENCES

[1]  T. Nissen, and D. Peterchuck, “Plan Ahead for Substation Automation”, in Proc. IEEE Power & Energy, Vol. 1, Num. 2, March/April 2003, pp.42-49.

[2]  D. P. Buse, P. Sun, Q. H. Wu, and J. Fitch, “Agent-Based Substation Automation”, in Proc. IEEE Power & Energy, Vol. 1, Num. 2, March/April 2003, pp. 50-55.

[3]  A. C. Weaver, “Monitoring and Control Using the Internet and Java”, in Proc. IECON 1999, PP.1152-1158.

[4]  M. Furuya, “WWW-Browser-based Monitoring System for Industrial Plant”, in Proc. IECON 1999, pp.1146-1151.

[5]  Adida, and B. Tacking, “Web Clients to the Next Level”, in IEEE internet computing, .Vol. 1. Nr. 2, 1997, pp.65-67.

[6]  R. P. Gupta and R. K. Varma, "Power Distribution Automation: Development and Implementation Experience", International Journal of Power and Energy Systems, Canada, paper number 203-3479, 2004.

BIOGRAPHIES

Ram Prakash Gupta received his B. E. degree in Electrical Engineering from Gorakhpur University, India, in 1984, and M. Tech. and Ph. D. degrees in Electrical Engineering from the Indian Institute of Technology, Kanpur, India. He worked as a faculty member in Kamla Nehru Institute of Technology, Sultanpur, India from 1985 to 1993 and joined IIT Kanpur in 1994. He is presently working as Senior Research Engineer in Department of Electrical Engineering at Indian Institute of Technology Kanpur, India. His research interests are in the areas of power distribution automation, substation automation, power system communication, software engineering, and IT applications in power systems. He is a member of IEEE, IEE (Japan), Institution of Engineers (India) and IETE (India).

Rajiv K. Varma did his B. Tech and Ph. D. from Indian Institute of Technology (IIT), Kanpur in the years 1980 and 1988, respectively. He was a faculty member at IIT Kanpur from 1989 - 2001. He subsequently moved to University of Western Ontario, London, Canada where he is an Associate Professor. His research interests are Flexible AC Transmission Systems and Power System Stability. He may be reached at rkvarma@fes.engga.uwo.ca.

 

 

 

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