GISdevelopment.net ---> GITA 2000 ---> Operations Support

Electric utility operational support using GIS

Bill Strongman
West Kootenay Power Ltd.
PO Box 130
Trail, British Columbia,
Canada, V1R 4L4

J. Lance Maidlow
Kanotech Information Systems Ltd.
Suite 200, 17704 103 Ave
Edmonton, Alberta
Canada, T5S 1J9


Background

The Company
West Kootenay Power is a small vertically integrated electrical utility servicing about 120,000 customers in the southern interior of British Columbia. It has 4 small (50 MW) hydro-electric generating plants, 950 miles of transmission lines and 5,700 miles of distribution lines (both overhead and underground).

Logic (Geographical Plant)
Electric utility plant is geographic by nature. Unlike other industries that have all the facilities in a small area, utilities have plant that is spread out over hundreds or thousands of square miles. Thus, the logical means of tracking facilities is through maps. A database linked to a mapping system allows information about the assets to be represented graphically. Inserting information through the mapping system allows for improved data management.

The Mapping System
The application architecture, developed by Kanotech Information Systems, has all data stored on an external SQL compliant database (MS Access) with only database keys maintained within the AutoCAD Map drawing files. A node-line structure was adopted for the basic database structure. In this model, each critical point (typically a pole or a pad) is defined as a node in the system. Each is assigned a NODE_ID and x, y and z coordinates. This information is stored in the system in a LOCATION_NODE table that is referenced by all other tables in the system.

Visual Basic was adopted as the primary development tool for database applications. The AM/FM inventory system utilizes a VB framework and a series of standard components that can be modified and updated as changes take place in the core technology. Bi-directional interfaces between the application and the underlying GIS software are provided by Kanotech's Universal Database Interface (UDI) which is a series of OLE Automation Servers.

The AutoCAD Map interface contains a series of automated drafting tools that make extensive use of AutoCAD Map Menus, Visual LISP and ARX utilities. These tools are designed to assist users during the drafting process and ensure that the correct symbology and layering is employed and that the database linkages are maintained. Utilities are also provided to permit users to update multiple database attributes simultaneously.

With this system, mapping technicians can produce standardized distribution plots showing all the distribution facilities, both overhead and underground for the regional operating divisions. In addition, specialty plots can be produced that show only information needed by the requestor. For example, a regional operating group may require a map showing only the underground distribution network in order to undertake a maintenance program.

The following are two examples of applications developed in support of specific areas of operations. Applications to support other operations have been developed or are under development.

System control
Distribution system control is the activity of issuing work control permits to ensure a safe environment for the crews. The permits ensure that, when devices are opened to "kill" a line, they will not be inadvertently closed in until the crew working in the area is clear. Tags are placed on the devices, and the main function of the Control Center is to track these tags.

Given the geographic area covered by the Company, paper maps were considered ineffective because hundreds of maps would be required if they were to be at a reasonable scale. Thus, the Company elected to develop an electronic application that would allow the control operator to view, zoom and trace facilities to determine control points for issuing work control permits.

There are three steps in developing an application of this nature. The first is to determine the "business process" which addresses the purpose of the application. Once that is established, the "functional requirements" are developed to examine how the application will work. From this, it is possible to then determine the "specific features" of the mapping system.

Business Process
The flow chart in Figure 1 defines the business process for the System Control application. The tasks were divided into pre-job tasks that need to be done before the job can start, day of job start tasks that must be performed before a crew can begin work, (e.g. permits issued, devices tagged), and job complete tasks that effectively closes the job. The flow chart also shows the interaction between the line crews and the System Control Center.


Figure 1. SCC/PIC Business Process


The process boxes should also be accompanied by textual explanations, for example: Pre-job processes
Under normal circumstances a permit request is made in advance of the work being performed. Usually 24 hours. The SCC will begin to fill in a card (e.g.: Live Line Permit) based on the information collected from the applicant. The various permit cards are pre-printed with a permit number already assigned. It is this permit number that will be used as the unique identifier that will cross reference the applicable graphic device symbols to the permit. The permit number will be re-keyed into the applicable form by the SCC operator.

It is assumed that the applicant will, at minimum, know what feeder number they will be working on. It will be the applicant's responsibility to provide enough information to allow the SCC to isolate the limits of the work area. Functional Requirements
As with the business process, the best way to determine functional requirements is to draw a flow chart (Figure 2). This will help to identify the functions that will be performed by the mapping system. The top row of boxes show the tasks performed by the operators as identified in the business process. The second row of boxes identifies the specific map related tasks performed by the operators.


Figure 2. SCC/PIC Functional Process


System Features
The numbered items in the lower boxes can then be used to develop specific system features.
These features need to be grouped into the following categories:
  • Source Data - where from, collection procedures, links to other data
  • Specific Attributes - what they do, edit rules
  • Displays/Reports - what they look like, on what software
  • Computer Hardware and Software - standard or special hardware, printer/plotter
  • capabilities, software "platform" Maintenance - where will it reside, who will maintain base files/data.
Using the above as a guideline, it was possible to prepare the system features for the System Control application. Typical specifications would read as follows:
  1. Source Data

    • The AutoCAD map and database information will be downloaded form the main mapping system that resides on a central server.

  2. Specific Attributes

    • The SCC will perform a geographic query that retrieves all the necessary distribution facilities based on the requested feeder name. The retrieved devices will be automatically displayed, allowing the user to visually identify the current status of all the devices. Any device having a permit assigned must be visually recognizable with its status evident.

  3. Displays/Reports

    • Current flood traced feeders will be red while all others will be set to white. Background will be black.
    • Devise numbers will be a text attribute displayed at each applicable device in a cyan color.

  4. Hardware/Software

    • The SCC will have a stand alone version of the mapping system on a separate server located at the Control Center. It will be linked to the main mapping server in order to download the source information. It will also be linked to a backup server at Head Office.
    • The Control Center will need two PC work stations with the 300 MHz, 130 meg RAM, 2 gig HD, Windows NT, 21" monitors, a Laser Jet Printer, and a color plotter.

  5. Maintenance and Support

    • General maintenance of the computer hardware will be provided by the IS Department.
    • Support for the AM/FM System will be provided by the Technical Services Department.
The complete list of functions is considerably longer but for the purpose of space, only the above examples are shown here to provide a general sense of how the functional requirements become specific features.

Vegetation management
West Kootenay Power must control the vegetation under and near its distribution and transmission facilities to ensure that electricity is safely distributed to its customers without interruption. Tall growing vegetation near power lines is a major cause of electrical outages. Tree/line contact can also create a public safety hazard.

The Company required a means of recording and tracking tree trimming and removal activities so that encroaching trees can be plotted on maps for brushing crews. Also, by utilizing information on vegetation growth rates and vegetation management costs directly from the database, West Kootenay Power staff will be able to create annual vegetation management plans for various budgetary scenarios.

Business Process
The business model presented in Figure 3 provides an overview of the business processes which will support the following:
  • provide historical information for vegetation planning purposes
  • generate annual vegetation management plans
  • execute tree trimming and removal activities
  • monitor progress and generate progress payment supporting documentation
  • evaluate effectiveness of work and contractors

Figure 3 Vegetation Management Business Process


Although not shown clearly in the above flow chart, the processes can be grouped into planning, execution and close phases. The boxes in the top left of the chart are the planning boxes, those in the middle are part of execution, and the completion box that feeds information back into the system is the close phase.

Functional Requirements
In this case, much of the data retrieval is in the form of database reports rather than maps, especially in the planning stage. Maps are only required in the execution stage to provide a visual display of problem trees so that contractors can find the sites. The functional process is shown in Figure 4 below.


Figure 4 Vegetation Management Functional Process


System Features
The following are examples of system features arising from the functional requirements:
  1. Source Data

    • provide a database to capture and store information related to hazardous trees, slashing and pruning.
    • The system will support extraction of sub-databases, by feeder, which will be provided to contractors for entering vegetation data.

  2. Specific Attributes

    • Hazard tree rating information will be stored in the database to permit West Kootenay Power staff to perform vegetation management scenario analysis by hazard rating.
    • Work conducted will be indexed by year to permit historical analysis .
    • The primary key in the database will be a SPAN ID which will remain consistent and will provide the master link to the AM/FM mapping data.
    • AutoCAD MAP based functions will be utilized to update feeder and management area fields in the database.
    • The existing AM/FM plotting functions will be utilized, to the extent possible, to provide the graphical interface to the vegetation management database.

  3. Displays/Reports

    • The system will generate maps identifying the SPAN ID and the work specified to be conducted using symbology approved in advance by West Kootenay Power. The existing West Kootenay Power vegetation management sheet surround, modified with final symbology will be employed.
    • The system will generated the reports required by the contract documents to be provided to the contractors. The format of this report will be defined in advance as part of the detailed specifications.

  4. Computer Hardware and Software

    • The system will include an AutoCAD Map utility which will permit West Kootenay Power staff to add new poles and spans and automatically update and maintain a master span id table.
    • The system will utilize a Microsoft Access interface, forms and wizards which will navigate non-technical users through the process of entering and maintaining database information.
    • The system will automatically extract a replicated database which will be supplied to the contractors for updating as part of their work program.

  5. Maintenance and Support

    • General maintenance of the computer hardware will be provided by the IS Department.
    • Support for the AM/FM System will be provided by the Technical Services Department.
A more complete and extensive list of specific features was used by Kanotech to develop the Vegetation Management Application.

Conclusion
A well developed mapping system is an invaluable tool for supporting operations in an electric utility. Given the geographic nature of utility plant, specific work to be performed on the electrical system can be planned, monitored and reviewed using map and database information provided by the mapping system.

The above are only 2 applications where the mapping system is utilized to support operations. They were presented here to give the reader an understanding of how an application can be developed, starting with the business process and working through to the final system features. In addition to the above, other applications are either developed or under development at West Kootenay Power, including: streetlight inventory, shared pole (with telephone and cable) monitoring and control, property tax analysis, and pole test management.
© GISdevelopment.net. All rights reserved.