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4. METHODOLOGY

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The DSS for electricity distribution (Figure 2) provides a user friendly Graphical User Interface (GUI), developed using Microsoft Visual Basic 6.0 as frontend with MS Access database as backend. This GUI Environment helps in entry, update of database along with the options to compute shortest route, category and energy analysis for selected locations.  

Figure 2. Overall Structure of the DSS  

4.1 DSS for electricity distribution

4.1 | 4.2

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The overall structure of the DSS for electricity distribution is given below. User interacts through GUI, which contains the following menu options.

•  Edit: to enter category and energy details.

•  Analysis: to do category wise and energy wise analysis at different levels.

•  Forecast: to forecast the future consumption.

•  Geographical Information System (GIS): to find the shortest route of the electrical networks.

•  Help: on-line help.

The user can select any of the five modules and the data for each of the module is retrieved from the database. The processed output is either stored in the database or given to the user. For finding the shortest route the digitised maps are given through the GIS. Kernel passes the data to the application manager. The kernel accesses the needed data from the database according to the Application manager's request through the help of the Data Base Management System (DBMS). Then processed data is given back to users. According to the analysis at various levels the application manager selects various levels from the electricity supply or from demand.  

4.2 Process Design of DSS

4.1 | 4.2

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The physical design for DSS is the software package written in Visual Basic as front-end tool and Microsoft Access as back-end tool. This DSS consists of 4 modules: electrical energy analysis, category analysis, forecast and shortest route.  

Energy Analysis

In this module yearly, monthly, daily consumption and loss of electricity is computed. First, it checks for the data in the database. According to the availability of data, analysis is done at district/division/taluk/substation/feeder levels. If the data is not available, then the required data has to be added to the database.

To compute the yearly consumption and loss of electricity, select the levels such as district, division, taluk, substation, feeder and then the year. Proceed if the data is present, else it will display the message “No Data”. If the yearly data is available then the computed result is the true value else the computed result is the average value (based on previous years consumption). If the selected level is district (division / taluk / substation / feeder) then total consumption of electricity of all the divisions under that district (or respective hierarchical level) is aggregated and displayed. The monthly and daily consumption and loss of electricity is computed in the similar manner for various levels (division, taluk, substation, feeder levels).

Category Analysis

In this module yearly, monthly, daily consumption and loss of electricity (category wise at various levels) is computed and displayed graphically. First it checks for the data in the database and then allows navigating at various levels (division, taluk, substation, feeder, etc.) according to the availability of the data. If the data is not available then the data may be appended to the database.

Forecast

The future consumption of electricity is computed based on historical data. This is based on regression analysis with the data of at least ten years/months. If the data is available for specified range of years in the database, the relation between x and y is computed that is used for prediction. Otherwise user has the option to append the required data.

Shortest Route

The distribution systems is modelled to provide a reasonable representation of the actual systems as well as to enable the relevant data to be stored and meaningfully applied in the analysis programmes. Identifying the suitable nodes and the corresponding sections between two adjacent nodes does this. The data with respect to the length of the line is included in the section data while the station details such as voltage etc., is stored in the node.

b) Digitisation of the model

After selecting the model the network and the load data can be input via the terminal or by use of a digitiser. The digitiser is used to enter all required spatial data (vector data), which is used in maintaining the necessary records as well as in presentation of line routes, substation and equipment locations. The data thus stored can be reproduced by use of a plotter or a graphics monitor.

c)  Computation of the shortest path

Particular taluk is chosen and the two nodes (source and destination) information is provided as input for which shortest route is to be computed. The algorithm used to compute the shortest distance is Dijkstra's algorithm. Here all the arc and node information is stored in a table called arc and node. From the arc table, number of nodes and their length is found and stored in a matrix A (m x n). The entries in the matrix are

A (i, j) =		Length, if there is a direct path between i and j
		infinite, if there is no path between i and j
		0 if i=j

Where, m : number of rows, n : number of columns, i : i^th th row and j : j^th column.

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