By Karen Steede-Terry, author of Integrating GIS and the Global Positioning System, a publication from ESRI Press.
In an area crossing three state lines (Montana, Wyoming and South Dakota), lies some of the most amazing natural wonders in the United States. Campers in the Black Hills rarely think about having enough electricity available to blow dry their hair or brew their morning coffee–nor do they think about the amount of work that goes into maintaining the power delivery system here.
Electricity is supplied to the region by Black Hills Power (BHP), headquartered in Rapid City, S.D. BHP was established in 1941, the same year Mount Rushmore was completed. BHP provides electricity to more than 57,000 customers in a 9,300-square-mile service area encompassing parts of western South Dakota, northeastern Wyoming and southeastern Montana.
Covering such a large territory in rugged terrain presented BHP with some challenges. To increase efficiency when sending crews into the field, BHP needed an accurate map of its distribution system and electrical lines, but found that its base map data was limited. Few rural towns had any digital road maps, and as a result, most background data was missing entirely. When new roads were built, it could take several months before the new roads made it onto the local map. BHP decided the time had come to adopt a new mapping system.
Enter Mark Lemery, a Black Hills Power customer services supervisor. Lemery and his supervisor, Ted Massey, were familiar with the small handheld GPS (global positioning system) receivers used for recreational purposes. In 1998, they saw a demonstration of the ProXR/S “backpack” GPS receiver from Trimble Navigation. Lemery said that as soon as he saw the demonstration, it became evident that GPS could help BHP.
BHP employs the Trimble ProXR/S for a variety of applications. The utility’s first priority was to map trail access points in remote areas. A trail map was necessary for new personnel who were not familiar with the Black Hills.
One feature of the technology that turned into an asset for BHP was the ability of the GPS to record attribute information in the field. Trimble’s software allows a user to create a data dictionary–a catalog of information that a user fills in when collecting GPS data. BHP uses the data dictionary to identify and record all of the construction components (transformer, ID number, meters) on each pole. This information provides a more comprehensive pole map database.
Besides mapping lines and access points, BHP used GPS units to record meter-reading routes. Meters need to be read within a certain timeframe each month. Time is lost if a meter reader is unfamiliar with a route. By using the GPS, BHP was able to create maps showing meters and the roads that access them.
Next, BHP decided to acquire better background data for all its existing highways, roads and trails. BHP used the GPS while driving roads and created an updated street map. The street map was useful when constructing electric lines in new subdivisions.
BHP also uses the GPS unit to map hazardous trees for tree-trimming purposes. Hazardous trees are outside of BHP’s official tree-trimming right-of-way, but could easily fall onto a power line during a storm. Using its geographic information system (GIS), BHP can better identify, predict and manage which trees will fall onto its lines.
BHP now has a complete and accurate system map that is accessible by all users in the power company. Using GPS to upgrade its GIS, BHP also has the capability to update line extensions for new subdivisions, rather than depend on another company to furnish background map information (which may not be up-to-date).
Black Hills Power uses GPS “backpack” receivers like this one to map service lines, meter reading routes, streets, trails and more.
By using GPS, BHP has increased its field worker productivity. During severe weather, maps can be created instantly that show problem areas, lines that are out, trees that potentially have been blown down, as well as where the access points are. Because BHP used the GPS to map trail access points and the trails themselves, that information can also be used for maintenance functions. Crews can be sent out with a map to inspect the integrity of lines.
According to Lemery, crews are more efficient simply because they now have better background data. BHP has implemented a pole inspection program, and can forecast which poles will need to be inspected each year. In addition to increasing efficiency, having an updated database has allowed BHP to be proactive in new line construction. In the field, a construction representative walks a route where a new power line needs to be built. Along the way, using some of the features of the ProXR/S, the construction rep can mark any features (for example, specific pole locations, corner poles) and obstacles of the new route. Back in the office, potential routes are downloaded to AutoCAD, where pole spacing requirements and other company construction standards can be incorporated into the design.
Accuracy is very important to BHP, especially when it comes to engineering analysis. Many queries are run in the GIS, where the answers are dependent on having collected sub-meter GPS data in the field. BHP is required to run various reports concerning line lengths and line distances from source to loads for various engineering analysis. One spatial query includes finding the number of poles inside each district for tax and accounting purposes.
Overall, Black Hills Power is pleased with the success of GPS technology and its integration into other in-house applications. Lemery said that once BHP started using the GPS equipment, it quickly became obvious how valuable it was for other company applications. In the end, BHP will continue to use GPS to increase its work productivity and efficiency.