In the last few decades, the electric power industries have been developing power transmission systems to follow up with the rapid growth of the power demand. On the other hand, the suitable site for new transmission lines has been getting restricted, because of development of rural areas and the growing concern over environmental issues. Analyses such as the selection of suitable areas, the optimum path finding, the profile analyses, the engineering design of towers and wires, and the cost estimation can be done using GIS. This will help planners and engineers in the environmental and engineering analyses for transmission line siting. Power industry consequently has to keep track of numerous poles, circuits, power lines, and transformers. Information of location, voltage, and distribution of electricity of these facilities seem to be very overwhelming. However, with the use of GIS, information can be better organized on a computer system linking the database to map. A GIS as well can make the information easily updatable and accurate and hence can cater to the needs of maintaining large power infrastructure. GIS can effectively manage information on the distribution of electricity to customers and information describing the attributes of each customer such as location and electricity use. Electric companies are already finding GIS very useful in management of distribution. Today in the power distribution sector not only GIS but combination with AM and FM is revolutionising this sector.
The electric utility industry has realized that GIS is a valuable tool not only for mapping facilities but to improve decision making and better managing infrastructure.. Although the needs and uses of GIS are slightly different in the power sector than other industries, GIS can be just as valuable an information technology in the electric utility industry.
AM, the Automated Mapping: This facility helps the utilities to quickly create digital maps of their supply area using the digitization facilities of the software. These maps when so digitised, contain detailed information about the land serviced by the utility, and the precise location and engineering information of the distribution network equipment of the utility that are installed in the field.
FM, the Facilities Management: The digitized map files that are so created with all the required intelligence built into them can now be used to satisfy the Facilities Management needs.
AM/FM/GIS in the field of electric power is used for
- The study and analysis for electrical distribution system, analysis and design.
- Applications are also being developed for tackling problem of designing the electrical supply system for new residential development.
- For process automation in order to provide their customers with high quality attendance.
- To rebuild the design of work procedures in electric utilities.
- GIS and GPS are also integrated for mapping and analysis of electric distribution circuits.
GIS in Power: Information Retreival
The maps created by using AM facilities can be made as intelligent as one can imagine. For example, if an engineer needs to know the date of installation of a given transformer, all that he has to do is to click onto that transformer symbol. The attributes attached to this transformer will appear in which one of the attributes will show him the installation date. Consider that the same engineer now wants to know more complex information. He only wants to see on the map, which are the 100 KVA transformers in a given area that were installed prior to a given date. The query facilities of the software will quickly process this requirement of his, and show on the map only those transformers that qualify his requirement, hiding all other transformers that do not qualify it. Let us assume that an engineer wants to know how many transformers are installed in a given locality. The software will quickly process his information need by taking the feeder network data and processing it within the a buffer zone showing the locality of the engineer’s interest and give him the results. At another time if he wants to assess the requirement of a cable to be laid along a certain road, the GIS will return him the results of processing considering even all the bends and turns the road may have. The cable length so shown by the GIS will be precise and will therefore help him procure the exact required quantity of the cable.
Fig. 1: Representation of a Powerline from high resolution Laser-Altimetre data, acquired by helicopter. (Courtesy: Eurosense)
GIS in Power: Maintenance & Monitoring
Let us assume that the engineer has to send a cable jointer in the field who has to access a certain underground cable joint. The engineer can take the digitized map file of the area, mark a small portion of that area in the neighborhood of the joint, and print that small part on a piece of paper. This printed map of that small area will show, to the jointer, the location of the joint with proper distance and bearing references to the nearby identifiable objects. With these references so readily available with the jointer, his work will be easy and quick. There will be no need for him to have any guesswork or to constantly contact the office for knowing the joint location.
GIS in Power: Site Identification
The remote sensing technology is being used for the identification of suitable sites for locating new hydropower projects. The conventional method could not be directly adopted in the inaccessible areas like Himalayas where the water resource potential is high by means of glaciers and intensive rainfall. Similarly the geological, structural configuration is essential to study to understand the strength and weakness of the area so that the project will be implemented in the suitable terrain (ex. aseismic). For geologic mapping, reflectance information of the rocks in the SWIR and emissivity of the rocks information in the TIR are very important. Again, remote sensing data available in the near infrared region (0.8 um – 1.1 um) provides clearly the contrast between land and water features can easily be discernable. Satellite imagery may be used for the identification of catchment boundary, drainage network, perennial streams, landuse and vegetation cover for these projects. Digitizing the elevation contours and spot heights from topographic maps and using capabilities of various GIS softwares may generate Digital Elevation Model (DEM) of these catchments. The catchment boundary, drainage network and location of major habitation may be overlaid on these DEMs for further analysis.
GIS in Power: Information Processing
Information processing is a key to improve productivity and cutting costs of excess work. Converting information to a computerized format in GIS is more useful and timely for electric utility. For example: GIS will allow to search and retrieve information stored on a server simply by pointing and clicking through user-friendly menus or typing requests in a Windows environment. GIS has a way of making work processes simpler through more productive use of time and information.
Importance of Data
Accurate and current information is vital to maintaining and improving customer service. With GIS, the electric companies will have the ability to improve customer service by better gathering and processing customer information. Through a computerized environment, a GIS can keep information on customers, accurate and current. Improving record-keeping, and making data accessible to more users in more useful forms is vital to improving customer service. Evidently, improving ways of record keeping and data access is possible with GIS; therefore, it can be a key to improving customer service.
Data Sources in GIS
Remote Sensing is modern technique in mapping sciences. It is now a major tool to map any area on earth’s surface for transmission of power. The planning for installation of large transmission towers needs proper planning. For this, updated base maps are required. Remote sensing imageries can help in updation of the available topographic maps. The recently launched satellites like IKONOS, IRS-1C,1D(PAN) having its very good spatial resolution of 1mt and 5.8mts through digital image processing techniques; it is able to identify even small features with the resolution as given above. To select site for putting new transmission towers and lines especially in hilly terrains, the density of trees, elevation differences has to be carefully studied in detail. In such cases, remote sensing is the main technology, plays a vital role for the preparation of database on landforms, landuse/landcover and related database. Integrating these information in GIS platform, it is able to generate three dimensional terrain model (DTMs) of the area, which can be further updated with the multidated satellite images and aerial photographsAlso Digital Photogrammetry is the potential technology to provide the informations on terrain elevation which has to be studied before locating site for transmission towers and lines.This has found great success in many European countries but yet to be implemented in the developing countries like India
Besides Remote Sensing the hottest stuff today in the transmission sector is Airborne Laser Terrain Mapping (ALTM) or Light Detection & Ranging (LIDAR) Mapping. Laser mapping produces data with accuracies equivalent to traditional GPS land surveys. But the laser mapping produces these elevation measurements at a rate faster than traditional methods. Since laser mapping provides detailed and accurate elevation information, it can be used at placess where access to the survey property is limited or prohibited. Its rapid turnaround time and operational flexibility give one the edge in competitive bidding situations.
LIDAR data due their typical characteristics are finding many new applications, which were not thought feasible hitherto with other data collection techniques. One such area is monitoring transmission lines. Long stretches of transmission lines can be mapped with speed to determine the exact location of the transmission towers, accurate topography of the corridor, and the encroachment by vegetation for modification and repair purposes.
High resolution DEMs are suited for inspection surveys of powerlines (Figure 1). From the randomly distributed points hitting the wires the wire-lines can be reconstructed by using 3-dimensional line detection and modelling software.
However, inspection does not only include the determination of deformations of the wires, but also the identification of obstructions present in the corridors. For example, deformation caused by trees or illegal buildings standing too close to the powerline path. Their rapid detection and evaluation allows maintenance crews to react fast and to prevent disasters. Also, the inventory of damage after bad weather circumstances can be done easily from Laser DEMs. The required high-resolution mapping necessitates the use of helicopters operating at low altitudes as recording platform.
ALTM can also be used to map rugged terrain like Himalayas for hydropower generation where it is impossible to survey physically using traditional methods. ALTM can be really effective alternative in such case.
Like any other business, power companies are also faced to take various decisions vital to the operations, growth, and management of its business. To take proper decisions, information must be collected and analyzed to its full extent. Knowledge about the physical assets of the enterprise is necessary to make strategic and operational decisions. Information on the facilities, what condition they are in, how they are connected together, is important in taking even a simple decision. With the use of GIS, power companies can collect and store a large amount of data that can be readily accessed and analysed. Strength of GIS is integrating data and preparing it for analysis or modeling apart from tying together data from various sources makes it an important tool for the planning and decision making.
Here are some examples from UNESCO Training Module on the Applications of Geographic Information Systems (GIS) for power sector.
|Using a GIS you can enter new data or modify existing data. This example shows a GIS interface that allows easy editing of geographic data and the display of related scanned documents.|
Trouble Calls Analysis
|Trouble call analysis is crucial for effectively maintaining adequate services to all the customers. A GIS can help to locate trouble spots and reroute the services without overloading the system.|
Model Power Flow
|This product provides GIS users with an interface tool for network analysis for power flow. Key concepts in any network-modeling interface include minimizing data redundancy and simplifying the model/management process.|
Inventory and Manage Entire Systems
|GIS can keep track of the conditions and locations for all the components in a system. The City of Denton’s GIS database contains location and descriptive information for all the different components of their electric system. City Operations and Electric Engineering departments use this information to manage entire system.|
|The Energy Company of Bogota uses a GIS to manage the distribution and supply of electricity for Bogota, Colombia. GIS helps them manage over 600 feeders, 36 substations, and thousands of transformers, poles, and switches.|
Manage Meter Reaing Routes
|Seattle City Light is considering using their GIS to manage their monthly electric meter reading routes. The routes are created using customer addresses and City streets contained in the GIS database. Routes are then color coded and labeled for easier identification. Using the up-to-date information in GIS ensures that the routes will reflect the most recent customer locations.|