Gis and Gps Based Preliminary Distribution System Planning

> NCEEERE 2008, Sikkim Manipal Institute of Technology, Sikkim – 737 132, INDIA 1

Abstract—The major objective of a utility is to supply the power demand with good quality of service, through proper planning of system. This has led to development of methods which can be used to aid the decision making process for selecting best alternative. Complexity of electrical distribution system is a major reason for introducing new technologies as GIS (geographic information system) and GPS (global positioning system) that carries out complex power system analysis e.g. optimization of networks, load forecasting in quick and effective manner.GIS technology has the facility to plan an electrical distribution network routing of plain as well as remote hilly areas. GIS can facilitate information about customer, inventory, routing of distribution line, economic analysis of routing at the stage of planning, overload conditions in the upcoming days, load flow analysis etc. A GPS technology can also serve with a very effective and useful way for planning of electricity distribution system network in conjunction with GIS.

In present study, the analysis of the existing route of the radial distribution system network of IIT Roorkee has been done. Existing network of a sample substation consists of 57 buses 56 branches, and 6 feeders. A 3-D model of distribution system network has also been prepared using a GIS and GPS technology. New layouts of the routing have been proposed on the basis of shortest feasible path. Best route among three has been selected on the basis of cost comparison. GIS and GPS may be considered as good tools for planning of electricity distribution network.

Index Terms— Distribution system network, Geographical information system, GIS, Global positioning System.

I. INTRODUCTION

Power generated at generation plants and sent to a network of high-voltage (440, 220 or 132 kV) transmission lines. These transmission lines supply power to medium voltage (e.g. 33 or 11 kV) distribution networks (distribution primary system), which supply power to still lower voltage

Manuscript submitted on June30, 2008. This work was supported in part by IIT Roorkee, India. This paper submitted in “National Conference on Emerging trends and advances in Electrical Engineering and Renewable Energy (NCEEERE - 2008) 22nd – 24th December 2008.

Priyanka Dixit, student M.Tech, Indian Institute of Technology, Roorkee, India, phone: +91-9717799755; e-mail: [email protected], [email protected] J.D.Sharma, Professor, Electrical Engineering Department, Indian Institute of Technology, Roorkee, India Phone : +91-1332-285889; e-mail: [email protected] M.K.Singhal, Senior Scientific Officer , Alternate Hydro Energy Centre , Indian Institute of Technology, Roorkee, India Phone:+91-1332-285167 e-mail: [email protected]

(0.44 kV) distribution networks (distribution secondary system). Both distribution network lines supply power to customers directly either three phase or single phase. Thus, the total network is a complex grid of interconnected lines. This network has the function of transmitting power from the points of generation to the points of consumption.

Electrical utilities require keeping a comprehensive and accurate inventory of their physical assets, for the provision of extending the network, undertaking maintenance, etc. Complexity of electrical distribution power system is only a reason for introducing new technologies as GIS (Geographic Information System) and GPS (Global positioning system) that carries out complex power system analyses e.g. optimization of networks, load forecasting in very less time period as and when required. GIS technology has the facility to plan an electrical distribution network which sometimes very difficult to access for surveying like remote hilly areas. GIS based software also have the facility to interface it with other software tools (e.g. MATLAB) design and analyze. It has a very vast area of application consisting electrical distribution system as one of them.

The distribution system is important to an electrical utility because its proximity to the ultimate customer and its high investment cost. The distribution system planning is necessary to fulfill the growing demand of electricity in an optimum way to make the techno-economic feasibility of the distribution system expansion. The planning of electrical distribution networks is a continuous development process for the customer point of view, increase in load demand and in Research & Development. Earlier it was done manually on road maps now among modern technologies; GIS can be helpful to solve the problems.

II. INTRODUCTION TO GIS AND GPS GIS (Geographic Information System) is "an

organized collection of computer hardware, software, which is used to capture, store, update, manipulate, analyze, and display all forms of geographically referenced database digitally."[1]

GIS technology integrates common database operations such as query and statistical analysis with the unique visualization and geographic analysis benefits offered by maps. These abilities distinguish GIS from other information systems and make it valuable to a wide range of public and private enterprises for explaining events, predicting outcomes, and planning strategies. The analysis uses the spatial and non-spatial attributes in the database to answer questions about the real world. Geographic analysis facilitates the study of real-world processes by developing and applying

GIS AND GPS BASED PRELIMINARY DISTRIBUTION SYSTEM PLANNING

Priyanka Dixit J.D.Sharma, M.K.Singhal Student, IIT Roorkee Professor, EED, IIT Roorkee SSO, AHEC, IIT Roorkee


models. Results of geographic analysis can be communicated with the help of maps, attributes or both. In electrical power distribution system GIS integrates the non spatial database of system to the spatial data. GIS software performs different analyses e.g. load flow analysis, load forecasting, route optimization and inventory control etc. in interfacing with other power system analysis software.

The Global Positioning System (GPS) is a technology, which provides accuracy and flexibility of determination of stationary or moving spatial objects. Its applications are navigation, surveying, remote sensing, mapping, and geodetic positioning. Geodetic positioning can be determined either in relation to a well-defined coordinate system, usually by three coordinate values or in relation to other point, taking one point as the origin of a local coordinate system. GPS uses satellites and computers to compute positions anywhere on earth. [2]

In electrical power distribution system for finding the location of any object e.g. poles, substations, transformers, tracking of routes etc. It gives the position in form of latitude and longitude, which can directly be imported on computer screen.

GPS are becoming very effective tools for GIS data capture. The GPS can easily be linked to a laptop, computer in the field, and, with appropriate software. Users can also have all their data on a common base with very little distortion. Thus GPS can help in several aspects of construction of accurate and timely GIS databases.

III. THE ROLE OF GIS IN DISTRIBUTION NETWORKS

Database plays an important role in the planning, where different software programs form a part of the system operated by a database management system which stores, retrieves, and modifies various data on the distribution network. The electrical utility for different operations requires record geographical information in the database. Distribution system required two types of geographical information related to network:

(a) Spatial Location and visualization, (b) Database or attributes attached to it. Interfacing of geographic with its database with analytical

tools makes the system more user friendly, takes less time to analyze, more efficient and low-cost power distribution systems These analytical tools are available with GIS based software. Thus GIS is a tool which operates the system both with its geographic and its corresponding attributes attached to it. Material management, inventory control, preventive maintenance and system performance can also be accomplished in a systematic and cost-effective manner.

IV. GENERAL DESCRIPTION OF GIS USED FOR 3D MODEL OF AREA OF INTEREST

In GIS based distribution system planning a platform has to be chosen. Here, a GIS based software ARCVIEW GIS 3.2a has been chosen for the analysis of the existing route of the radial distribution system network of IIT Roorkee, India. A three dimensional model of distribution system network has also been prepared using GIS and GPS technology.

The various aspects can be analysed by the model of network prepared in GIS and data available with the geographic (attributes):

• Optimum feeder path, • Proposal for different layouts for future

expansion, • Selection of optimal conductors, • Load Flow analysis, • Cost comparison among different layouts, • Database management, • Inventory control,

In this study modeling of electricity distribution system of IIT Roorkee, INDIA has been done using GIS (Geographic Information System) and GPS (Global positioning system) technology. Distribution system network of IIT Roorkee consists of 12 sub-stations with different feeders for different areas and three underground grids of 11 kV connecting these sub-stations, which are coming from 33kV sub-station. A three dimensional model is build in geographic and all the related database is attached to the geographic. The data related to the distribution system is attached with the geographic. For obtaining a map in GIS based software i.e. ARCVIEW GIS 3.2a map of that area is required, that map may be in the form of a topographic sheet, a road map, a satellite image or an areal photograph of the area of interest. Here a satellite imaginary of IIT Roorkee is available in fig 1 as a map for digitization. The graphical representation of the network of these feeders and results obtained by the software is another feature of the work. The relevant information about the feeder such as feeder name, segment number, and type of conductor used, length of the segment, etc. can be obtained by attributes attached with the graphic. Technical aspects of the proposed layout can be understood on the basis of corresponding power flow analysis and cost comparison. "Every object present on the Earth can be geo-referenced", is the fundamental key of associating any database to GIS. Here, term 'database' is a collection of information about objects and their relationship to each other and 'geo-referencing' refers to the location of a layer or coverage in space defined by the reference co-ordinate system. Satellite imaginary is now georeferenced by taking a few control points on imaginary and their latitude and longitude using GPS technology. Different layers e.g. road, building, open space etc. are being digitized in ARCVIEW 3.2a. After digitization the topology of all the features is built e. g. all the buildings, roads and ground will be built as a polygon. Fig 2 shows the digitized map of IIT Roorkee on satellite imaginary. Fig 3 shows the Complete digitized map of IIT Roorkee in view window of ARCVIEW GIS 3.2a with built topology of all the features.


Fig .1. Satellite imaginary of IIT Roorkee opened in view

window of ARCVIEW GIS 3.2a

Fig .2. Digitized map of IIT Roorkee shown in view window

of ARCVIEW GIS 3.2a on satellite image

Fig .3. Complete digitized map of IIT Roorkee shown in

ARCVIEW GIS 3.2a

Due to the poor resolution of the satellite imaginary, the location of the poles and feeders is not available hence for locating all the poles GPS technology is being used. Location of poles in the form of latitude and longitude will be stored in a GPS instrument during survey and can directly be imported on the digitized map. The location of the feeders now can be drawn between the poles. Fig 4 shows the data of location of poles with its latitude and longitude and also corresponding location on the world map using GARMIN’s GPSMAP. Fig 5 shows the location of poles on world map at a 800 feet zoom level.

Fig .4. Location of poles with latitude and longitude in left

window and corresponding location on the world map in right window at 300 miles zoom level in GPSMAP software.

Fig.5. Location of all the poles of IIT Roorkee at 800feet

zoom level GPSMAP software.

Fig .6. Location of poles imported on ARCVIEW 3.2a from

GARMIN’s GPSMAP

Fig .7. Location of poles and feeders of distribution system

network of IIT Roorkee


The location of poles collected during survey from GPS has to be imported on GIS software. GPSMAP is compatible with other software to transfer its data. Fig 7 shows the imported data of poles of distribution system network of IIT Roorkee from GPSMAP to ARCVIEW3.2a in geographic. Fig 8 shows the complete 2-D map of distribution system of IIT Roorkee prepared with GS and GPS technology. It shows the layer of roads, buildings. poles and feeders.

Fig .8. Complete 2-D map of distribution system of IIT

Roorkee

Fig .9. 3- D model of distribution system network of IIT

Roorkee GIS has the facility to convert a 2-D image in 3-D

either by contour elevations or by using the height of the buildings. The3-D model of existing distribution system network of IIT Roorkee has been prepared using ARCVIEW GIS 3.2a as shown in above fig 9. Spatial parameters of distribution system can be found from the model of distribution system of IIT Roorkee prepared in GIS. To find out the optimum routing using GIS one substation as a sample has been selected and three layouts of routing have been proposed on the basis of shortening the length of the feeders and routes should be feasible also. Conductor selection has been done on the basis of kW-km. these data are available in attributes. The lengths of the feeders of three proposed layouts have been measured from the GIS model shown in fig 11,12,13 and given in table1. Cost comparison of the three proposed layouts is done on the basis of lengths available. Fig 10 shows the location of sample sub-station on 3-D layout of the exiting system.

Fig .10. Layout of existing routing of sample substation

Fig .11. First proposed route for sample substation with

loading of blocks and pole attributes

Fig .12. Second proposed route for sample substation with

loading of blocks and pole attributes

Fig .13. Third proposed route for sample substation with loading of blocks and pole attributes


Table.1. Lengths of existing and proposed feeders of sample sub-station measured through GIS model

Existing feeders Layout: 1 Number of feeders=6 Number of feeders=5

Feeder name

Length (m)

Feeder name

Length (m)

Vikas Nagar 640 Vikas

Nagar 315

Saraswati KunjA 615 Saraswati

Kunj 835

Saraswati KunjB 391 Community

hall 335

Community hall 373 D-class 738

D-class 1257 Solani kunj 734 Solani kunj 907 Total 4183 Total 2957 Layout: 2 Layout: 3 Number of feeders=6 Number of feeders= 5

Feeder name

Length (m)

Feeder name

Length (m)

Vikas NagarA 302 Vikas Nagar 561

Saraswati Kunj 574 Saraswati

Kunj 515

Solani kunj 900 Community hall 400

D-class 622 D-class 657 Vikas

NagarB 423 Solani kunj 804

Community hall 373

Total 3194 Total 2937 Table1 shows a good reduction in length of feeder

conductors by rerouting, which indicates saving in power loss also. Now among three on preliminary basis a cost-effective route can be selected.

V. COST COMPARISON AMONG PROPOSED LAYOUTS

Cost comparison among the proposed layout will finally select the optimum one. This has been done on the basis of the cost of accessories used in the distribution network viz. conductor, poles, stay wires, cross arms etc. The cost of other accessories is calculated in table 3 used in different layouts. Annual losses can be calculated in table2. For Resistance of the branches length is available with map in GIS software.

Table: 2 Feeder lengths, type of conductor and annual losses of existing and proposed routes

Existing feeders: Number of feeders =6

Feeder name

Length (m)

Loading kW(max)

Loading (kW-km)

Type of conducto

r I2R (kW)

Annual Losses(Rs

) Vikas Nagar 640 230 147.2 dog 14.8125 272491

Saraswati KunjA 615 256 157.44 dog 12.4844 229662

Saraswati KunjB 391 240 93.84 weasel 7.97935 146788

Community hall 373 60 22.38 cable 4.32379 79540

D-class 1257 321 403.497 dog 25.7349 473418 Solani kunj 907 456 413.592 dog 27.8692 512682

Total 4183 1563 1714581

Layout: 1 Number of feeders =5

Feeder name

Length (m)

Loading kW(max)

Loading (kW-km)

Type of conductor I2R (kW)

Annual Losses(Rs

) Vikas Nagar

315 110 34.650 Squirrel 22.5245 414360

Saraswati Kunj

835 616 514.360 dog 13.2740 244188

Community hall

335 68 22.780 cable 4.9923 91839


Total 2957 1563 1075291

Layout: 2 Number of feeders=6

Feeder name

Length (m)

Loading kW(max)

Loading (kW-km)

Type of conducto

r I2R (kW)

Annual Losses(Rs

) Vikas NagarA 302 110 33.220 squirrel 21.5949 397260

Saraswati Kunj 574 496 284.704 dog 10.5900 194813

Solani kunj 900 456 410.400 dog 18.2830 336335 D-class 622 233 144.926 dog 10.2771 189057 Vikas NagarB 423 200 84.600 weasel 25.7570 473826


Total 3194 1563 1693547 Layout: 3 Number of feeders= 5

Feeder name

Length (m)

Loading kW(max)

Loading (kW-km)

Type of conducto

r I2R (kW)

Annual Losses(Rs

) Vikas Nagar 561 336 188.496 dog 11.0101 202542

Saraswati Kunj 515 390 200.850 dog 3.2290 59401



Total 2937 1563 944015

The comparison of complete cost of the entire layout

will decide the optimum layout. This is shown in table 4, the comparison shows that overall expenditure of layout 3 is least than other two. Hence it can be concluded that layout 3 can be selected as the cost-effective one from the economical point of view.


Table .3. Complete cost of accessories of all the layouts

Layout-1

Item Unit cost (Rs)

No. of Items used

Total Cost (Rs)

Number of poles 9000 82 738000

Stay wire 2120 21 44520 Insulators 61 388 23668 Cross arm 156 16 2496 Conductor 26327.2 Miscellaneous L.S. 20000 Total cost (Rs.) 855,011

Layout-2 Layout-3

No. of Items used

Total Cost (Rs)

No. of Items used

Total Cost (Rs)

94 846000 78 702000 22 46640 16 33920

436 26596 348 21228 17 2652 9 1404

25726 24353 20000 20000

Total cost (Rs.) 967,614 802,905

Table .4. Comparison of complete cost of all the layouts

Layout Total annual loses (Rs)

Total cost of accessories(Rs)

Total cost (Rs)

Layout-1 1,075,291 855,011 1,930,302 Layout-2 1,693,547 967,614 2,661,161 Layout-3 944,015 802,905 1,746,920

VI. CONCLUSION GIS based electrical distribution system planning is

an area of great importance. This study presents the 3-D modelling of distribution system network of Indian Institute of Technology, Roorkee, India, using GIS (Geographical Information System) and GPS (Global Positioning System) technology. GPS technology has been used to locate those features which are not available in the satellite imaginary due to its poor resolution e.g. location of poles. The whole system has been assumed to be balanced. The database management of distribution system of IIT, Roorkee is also attached as the attributes to its 3-D model. Rerouting of the feeders on the basis of shortest and feasible route using GIS based software

is done for a sample substation. Different possible layouts of shortest and feasible routes have been proposed using ARCVIEW3.2a and length has been measured. Reduced lengths of feeders result in reduction of power losses. Optimum Conductor selection according to loading and length i.e. kW-km is also considered for minimisation of losses. Among different proposed layouts of distribution system network, selection of the cost-effective layout has been done on the basis of cost analysis. Economic viability is a major consideration for cost-effective route selection.

Thus GIS & GPS technology is the versatile tool for the planning and optimisation of the electrical distribution system network. It is especially useful in hilly terrain as well as for the plain areas where the accessibility to the area is difficult for the route survey.

ACKNOWLEDGMENT We are indebted to the Alternate Hydro Energy Centre,

and Department of Electrical Engineering, Indian Institute of Technology Roorkee, India for having provided me with the opportunity to carry out this Study.

.

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Gis and Gps Based Preliminary Distribution System Planning