Kolkata-based CESC, the first power utility in India to implement GIS way back in 1992, is looking at completion of the entire project by this year and gearing up to reap the subsequent financial benefits
CESC Ltd is a private electricity utility company that generates, transmits and distributes power to the twin cities of Kolkata and Howrah, and its environs in the state of West Bengal in India. The company has been in business since 1897 and has grown from a licensed area of mere 14.61 sq km to a command area of 567 sq km.
The first electricity utility in the country to implement GIS in 1992, CESC started with converting the important graphical data such as maps, single line diagrams, sketchbooks and route cards to computer files with the help of AutoCAD way back in 1987 as it faced problems in manual maintenance of records. Beside huge physical volume and poor condition of documents, the problem areas were high maintenance costs, transcription error and wastage of manpower and time. Difficulty in data update and validation, and lack of easy access to operational staff were other major issues.
The company has four generating stations, over 100 sub-stations with an installed capacity of 1,225 MW and 2.65 million consumer base. It has about 6,000 circuit km of extra high tension/high tension (EHT/HT) transmission lines and over 10,350 circuit km in AC low tension (LT) distribution.
Embarking on the GIS path
The utility first started looking at GIS solutions in 1990 while converting to AutoCAD files some Survey of India (SOI) maps dating back to 1940s. The need to merge the graphical record of an installation with its non-graphical data was felt to build a comprehensive system on a single platform to make monitoring and updation of data easier.
The company embarked on the GIS project in October 1990 and by May 1992, the system for HT was launched since the records (both graphical and non-graphical) for HT were more or less updated with a fair degree of precision.
Each of the 32-inch maps were first scanned and converted to raster files. The raster files were then digitised and converted into vector files. A grid system was designed (with XY coordinates) so that after digitisation each map would automatically align itself to its correct position vis-a-vis the other maps. Electronic edge matching was carried to produce a seamless map covering the entire licensed area. The non-graphic data was then co-related to the electrical feature on the map through unique codes and default values were given wherever there was no data. This was then converted into the GIS environment through a migration tool. Finally, a thorough quality analysis was done to ensure maximum accuracy of the converted data. The process didn’t require physical survey work.
The final HT GIS map
However, there were two major disadvantages. The map was not geo-referenced and so no latitudelongitude data was available. Secondly, the land base contained only those roads that existed in 1940s and were mapped by the SoI. There were no other land base features such as buildings, water bodies, open spaces, parks, footpath, railway and tram tracks etc.
But when the system went live in 1992, the advantages far outweighed the above deficiencies. The immediate benefits were easy access to data for the operational staff, easier data updation, layered depiction leading to clarity, merging of graphical and non-graphical databases on one platform, online validation during editing and updation before acceptance in the database.
But the real problems arose at the LT network and consumer indexing phase. The requirements were far more stringent. The requirement was for a proper geo-referenced land base having latitudelongitude and accurate incorporation of all land base features, especially buildings, since the ‘last mile’ electrical network stopped there. There was also the need for accurate and up-to-date LT network with all elements in place and connected to each other in the proper sequence ‘electrically’. The GIS software was also expected to provide network tracing facility since that formed a vital part of the system.
Putting the system in place
For the consumer indexing project, CESC either did not have adequate data or what it had was sketchy at best. To ensure that the work was carried out smoothly, a GIS review committee and a GIS technical cell were constituted. Vendors were short-listed for preparing the land base and electrical network through detailed site surveying. A GIS network updation centre was formed with AutoCAD operators trained by the cell members in the GIS environment to update the LT network directly into the ‘live’ database.
The greatest obstacle was the preparation of the land base since there were no records available with the local authorities. Finally, the company decided to prepare the land base from Google Earth Pro Maps that had sub-metre accuracy and were updated every six months. The relevant portions of the map were downloaded, digitised and then rubber-sheeted to ensure correct coordinates by taking DGPS reading of a certain overground electrical installations having sufficient height. This method was found to be quicker and slightly cheaper.
The LT network was handed over to the survey vendor so that not only was the land base features surveyed, but the electrical features were also plotted on the map at the same time. The end product was a fairly accurate GIS environment containing the land base and electrical features. To update the network, the NUC was provided with six groups to survey and update the electrical network of their corresponding areas. The finished product was to be handed over for upkeep to the department concerned.
Final output of the GIS map
A customised web-enabled browser was put in place for viewing the GIS data and its company wide use was commissioned in August 2011.
As for consumer indexing, six years after the project was kicked off, GIS-based services were launched by January 2013 in three of CESC’s 10 LT network operational districts. The remaining seven are being made ready to go live within this year.
The result is there for all to see. In addition to immediate and better services to customers, the GIS system is helping the power utility identify and filter theft-prone areas. It is also helping in load flow analytics — which transformer is off and where there is more load. As a result, CESC has witnessed a drastic reduction in time to respond to consumer complaints. Another major advantage for the company is asset management.
Now, other departments within the company are also interested in accessing the data for efficient operations in their own areas. CESC feels this is especially true for CRM data, and if interfaced properly with DMS data, will open another vista of operational efficiency in attending to consumer complaint calls.