subject: Leveraging GIS application in Power Distribution Sector [print this page] Leveraging GIS application in Power Distribution Sector
Introduction
The Power Distribution Companies (DISCOMs) constantly need to update their consumer data and the corresponding electrical network attributes. The consumer database has to be indexed and show the relevant linkages with the Distribution Transformer (DT), Feeder and Substation. All the important attributes of the consumer (Consumer ID, Division Code, Service Connection Number, Address, Meter details, Network details, Contact details, etc.) need to be maintained in the database. The information of the consumer's network connectivity is also maintained in the database. The consumer database is mapped with network or assets database for defining the consumer's electrical connectivity.
GISis a handy tool for maintaining consumer database and graphically depicting the consumer's electrical connectivity on a digital map, using a GUI interface. The entire electrical network can be overlaid on a GIS base map or satellite image having sufficient resolution to identify the network element. Using the GIS application, when a particular DT is selected, then all the LT lines connected to that DT and consumers connected to respective LT line can be displayed. The software generates a color graphic map of the distribution network with the facility for zooming, resizing and scrolling.
Prerequisites of GIS application development
It is important to emphasize that door-to-door GPS survey helps not only in geo-referencing and digitally mapping the electrical consumers on a GIS map, but also identify the source from where electricity is supplied. Each consumer is allotted an alphanumerical code that would uniquely identify the Division, Subdivision, Substation, Feeder, Load category and eventually the Distribution Transformer to which the consumer is connected. The purpose of GIS application is to index all the consumers and categorize the complete consumer database with respect to their unique electrical address.
This exercise also helps the distribution utility in detecting unauthorized connections, fictitious (ledgerized but non-existent) connections or connections that are existent, but not ledgerized. Thus, the GIS mapping and indexing of consumers helps in determining the factual position of the electrical connections on the ground.
Another key requirement of a successful GIS implementation is the seamless integration of spatial data with other utility application databases viz. Customer Information System, AM/ FM, Utility Billing, Trouble Call Management, etc. The GIS application must stitch together other utility applications on a common fabric for cross-application portability of data.
Key functionalities of GIS application in Power Utility
GIS application covers the whole gamut of Power Utility operations. Some of the key functionalities of GIS application allow management and tracking of Utility field assets, Operations management and Work management as enumerated below:
Asset Management
Spatial Network Data Management
Asset specifications Mapping
View/Query/Analysis
Network Mapping
Operations Management
Outage Management System
Resource Management
Mobile Workforce Management
Customer Information Management
Single Line Diagrams
Work Management
Network Design/ Plan Layout
Network Laying/ reconfiguration
Cost Estimate preparation
As-Built Field Updates
Load planning and forecasting
4-step Digitization Process
The digitization of electrical network assets, consumer indexing and network mapping is a 4-step process, as explained below:
GPS survey of electrical consumers and network assets Door-to-door survey, identifying all consumers and their service connections
Preparation of GIS base map overlaid on the satellite imagery
Digitization of electrical network assets (33 KV Substation, 11 KV Feeders, DTs and electric poles) Use of differential GPS to establish geo-coordinates with acceptable accuracy
Establishing their electrical connectivity with respect to the Pole, DT, Feeder, Substation
Matching the survey data with the utility's ledgerized commercial records
GIS mapping, indexing and codification of electrical consumers and network assets with defined electrical relationships Collecting and updating data for every consumer with respect to DT, including additional information viz. condition of the meter, load type, sanctioned load, connection status, phase details, etc.
Identifying fictitious connections, i.e. those that exist in the ledger but physically non-existent
Interoperability and data portability among GIS and other utility software applications (Fig. 2) Customer Information System
Asset Management/ Facility Management
Trouble Call Management System
Utility Billing and Energy Accounting System
Load Flow and Load Growth studies
GIS applications in Power Distribution
Availability of accurate GIS-based distribution network map showing the geo- coordinates and network configuration is an important prerequisite for analysis, planning, optimization and load flow studies. Using GIS application, all network assets (HT/ LT Feeders, DTs, Poles) can be indexed with respect to a well-defined alpha-numeric code, which uniquely identifies the particular network element (Fig. 3). The coding is based on a structured pattern which allows the insertion of new components into the system. This coding also facilitates quick sorting and mapping of the network element on the GIS map.
The GIS application is GUI-based and facilitates on-line query with a graphic display of network section, showing the particular network element and also the corresponding network information on the pointer tool-tip. The GIS application also displays the geographical location of all consumers, their electrical connectivity and associated technical parameters, on query.
When integrated with the Customer Information System (CIS), it provides compete information of the consumer on the basis of the unique identification code the Consumer Index Number (CIN). The CIN in turn identifies the DT, Feeder and Substation through which the consumer is supplied electricity. This information is of great help in Energy Audit, Trouble Call Management, Asset Management, Load Management, Network Planning and analysis.
Checklist for successful GIS implementation
Proper GPS survey and creation of an accurate digital base map for the distribution network are essential prerequisites for successful GIS project implementation. GPS survey requires a GPS Base Station at a pre-determined location, aided by adequate number of GPS Rovers/ Receivers. Surveyors walk along the HT and LT feeder with a GPS Rover/ Receiver and capture the spatial position of the Pole, DT, Feeder and Sub-station and heavy consumers. GPS Base Station and Rovers provide the desired accuracy after differential correction.
The attribute data of the distribution network (DT and Conductors) is also collected in the process, such conductor make, type and size, DT make, type, impedance and capacity, etc. Differential correction has to be performed on the spatial data thus captured.
The digital base map must show the important landmarks like Roads, Rivers etc. which is necessary for easier identification of network assets and plan new distribution network. For better visualization, the vector map of the network can be overlaid on the base map or even the satellite image.
The latitude and longitude (spatial data) of important landmarks or control points must also be captured using the GPS instrument. The GIS application must be able to stitch together contiguous maps sections on the same scale into a continuous mosaic.
Conclusion
GIS provides a wide range of solutions encompassing the entire business value chain in the power distribution sector from setting up distribution network and load management to customer information, assets management, billing and customer services. However, the interfaces between GIS and other utility software applications should be well-defined.
GIS application must be designed to integrate seamlessly with other utility business applications. Continuous updation and monitoring of data is critical in any GIS application. Therefore, for any GIS application, it is important to have in-built process control checks, audit trail and exception reporting facility to ensure reliability and accuracy of data.
