Role of GIS as a decision support system in power transmission

Role of GIS as a decision support system in power transmission

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Introduction
Operational & Maintenance requirements of Utility lines sector require a multitude of data elements. For instance, tremendous amount of data is required to maintain the ribbon-like corridors that Transmission lines weave through the landscape. Property ownership data element is of particular importance to right-of-way (ROW) maintenance. Powerline characteristics are another collection of data elements that describes the physical characteristics of the line, its current condition, and that which is being transported through it. The physical characteristics of the lines are determined during construction & forms dynamic data elements which is required for engineering planning & other analysis.

The data elements (Landuse/landcover, ownership and powerline characteristics etc.,) which has both static and dynamic componants pose a formidable challenge for proper maintenance and operations in a utility sector. Key factor of efficiency in the work flow is automation of technological processes applied to data gathering, integration and processing, production of complete topographic products and their customized presentation, analysis and interpretation. The automation can been achieved by employment of:

  • Complete set of modern data gathering remote sensing devices such as airborne laser locators, digital aerial photo cameras, thermo vision devices with digital output equipped with GPS and inertial navigation system.
  • Proprietary software for integration and processing data collected by the airborne remote sensing devices and for presentation complete information product in a format compatible with common CAD and GIS applications as well as customized applications required by the operation managers of the utility sector.

This paper will outline the utility of Remote Sensing & GIS technology in a case of Transmission line utility sector for 1) High speed data acquisition of Transmission line networks 2) Photogrammetric processing in integrating the Airborne acquired data with a GIS system 3) maintain the critical facility database 4) Support of a Desktop GIS system in Maintenance and operational requirements.

Utilities Management through Spatial Technology Tools
Utilities need detailed information about the location and condition of their transmission corridor assets and right of ways to quickly and efficiently maintain and service them. To accomplish this, utilities need to regularly inspect and collect accurate spatial data of their facilities. Also the data must be wrapped in an enterprise system, which would support planners and managers in all the phases of utilities management.

Present day advancements in the spatial technology of Remote Sensing & GIS provides variety of tools in extending support to utilities management. To broadly classify the framework wherein the Remote Sensing technology & its tool of GIS fits into a utility sector can be divided into the following overheads of operations;

  • Assets inspections & inventory.
  • For various Spatial Analysis (e.g. Distribution planning, Mapping, routing to transmission poles, terrain analysis, transmission pole siting etc.) in support of utilities managers.

Utilities sector have employed a combination of techniques to address the first scenario of asset inspection & inventory, which includes ground surveys and aerial photogrammetry. These techniques have the extensibility to provide improved accuracy in location, visual identification of issues regarding rights-of-way, property lines and potential safety hazards, high-resolution digital images for performing detailed inspection, digital information capture for seamless export to a GIS environment, a terrain baseline identification which can be useful for regulatory and legal purposes, and data archival capabilities for temporal analysis.

The management and analysis of enormous amount of data generated in a utilities management sector is a daunting task. An enterprise system is needed to address issues such as:

  • Inspection & Assessment of Overhead Lines
  • Routine Inspection.
  • Safety Code Compliance Inspections.
  • Facility Inventory (Poles, Structures, Towers, Pad Mounts).
  • Maintenance Planning and Forecasting
  • Documentation of Component Conditions and Maintenance Needs.
  • Right-of-Way Management
  • Vegetation Management and Tree Trimming.
  • Weed Management.
  • Facility Mapping.
  • Animal-Caused Outage Studies.
  • Migratory Bird Collision Studies.
  • Inspection & Assessment of Overhead Lines
  • Powerline Routing and Permitting
  • Thermal Rating Studies
  • Access Planning
  • Emergency Response Planning
  • Environmental Studies

The task highlighted is only the core functional tasks in inventory, Planning and Engineering operations of a utilitiy sector.

The spatial components in the functional requirement can be effectively addressed by an integrated GIS system. It is imperative that a flexible framework has to be identified to address the requirements of the multi-faceted Utilities industry.

The following section highlights a framework of solution for Spatial Data capture using Aerial Photogrammetry and an integrated desktop GIS system in support of typical functional features in a Transmission line utility sector.
A case of Work Flow in Transmission Line Utility Sector

Spatial Data Capture Process
InfoTech’s Photogrammetric division, identified the framework for processing the data acquired in aerial photogrammetry in a format directly integrateable with a GIS system.

Figure 1.0 illustrates a possible scenario in data capturing using a Air borne techniques & the associated processing for data product generation. Table 1.0 list and compares conventional techniques in spatial data capture process & their relative merits.

Design of Desk Top GIS System to Support Utility Managers in Maintenance & Operations

InfoTech’s Geographic Services team worked in identifying crucial requirements in utilities services and developed a pilot architecture in addressing the same. The primary task of the team was in design of a desktop Transmission Line Reviewing system which would address points such as:

  • Spatial data integration acquired from Aerial Mapping
  • Inspection & maintenance
  • Engineering & planning operations
  • Real Time Routing
  • Integration with conventional tabular database
  • Report generation
  • Vegetation Management

The system flow designed is outlined in figure 2.0 below. The Framework of the architecture consists of Clients, Services, and Management. ArcView GIS (Desk top GIS product of Environmental Systems Research Institute Inc.,) provides the basic high-end geographic information systems (GIS) and mapping services for the GIS functionalities that are required for the application. The entire framework of the desktop system can be customized in a single user interface through the customization environment Avenue, available in ArcView.

ArcView GIS offers the extensibility to attach additional features to the primary design, such as the extension 3d analyst can be interfaced with the design for terrain analysis, line of sight analysis and other 3 dimensional analysis that might arise in a typical Transmission Line operations and maintenance.

The Network Analyst extension support the users in routing analysis such as routing to any transmission line facility with turn-by-turn directions, accurate travel time calculations and distance figures.

Image Analyst extention for analysis of Digital imageries for cases of temporal analysis, vegetation growth study, Thermal anamolies detection etc.

The Sag analysis of Power Lines can be addressed by integrating ArcView with SagSec (a product of Powerline Systems Inc). This module can support users in

calculating the section static equilibrium configuration for arbitrary combinations of: 1) sagging conditions, 2) wind velocity and direction, 3) balanced or unbalanced ice, 4) temperature, 5) broken conductors or insulators, 6) slack redistribution through offsets or other means and 7) support relocations with a fixed length of cable between the dead ends etc.

Tabular data integration with ArcView GIS is achieved by ODBC support to custom RDBM’s. Report generation feature can be handled by Crystall Report access within ArcView GIS. Optionally, depending upon the operational constraints, the spatial data can be stored in a RDBM’s and interfaced with the desktop system via the Spatial Database Engine interface through ArcView.

Benefits of the Integrated Desk Top Transmission Line Management Support System
The explicit benefits associated with an scaleable architecture described above are a point in question as far as any utility sector is concerned. The architecture aptly mixes the best of available “Commercial Off The Shelf” software in addressing the core requirements of a typical Transmission line maintenance & operations scenario.

The framework reduces the need for long term development of solution in one single vendor application, rather it extends as a “plug-in” kind of environment wherein additional features can be incorporated as and when the need arises.

Further advantage offered in the framework is the evolution of the desktop GIS environment ArcView into the latest ArcGIS architecture, which is open for customization in industry standard language and also extensible for support in both desktop and Internet environment.

Conclusion
Power is an integral part of any country’s infrastructure. Today, more than 100,000 MW of installed capacity powers India. The facilitating policy framework, the regulatory mechanism for investment in generation, transmission, distribution and other associated activities have already been put in place by the government. The need of the hour is for efficient management and optimum utilization of installed capacity to meet the demand.

The paper highlighted the salient points of Remote Sensing and GIS technology in addressing the utility sector needs and effectively drew a framework of operation in a typical Transmission Line Utility sector. The utility sector should capitalize on the advancement in the Spatial Technology to envision our government’s policy plan of “Power on Tap” by 2012.

Acknowledgement
We thank Mr. B.V.R. Mohan Reddy, Managing Director, InfoTech Enterprises Limited, Mr. Rajeev Lal, Chief Operating Officer, Dr.Nagesh, Division General Manager, who have been a constant source of dynamism and inspiration to all of us. We are also thankful to all our associates who are the players behind the screen.

Reference

  • Thomas, Helmer, 2001, “ArcGIS 8 Enabling Energy Delivery Resource Planning (EDRP)”, ESRI International User Conference.
  • Richard,Vann, 2000,”Populating a GIS of Utility Corridor Assets using an Integrated Airborne Data Acquisition System”, ESRI International User Conference.