Development of an ArcIMS for Ownership Identification and Service Differentiation of Electric Utility Lines

Transcription

1 Development of an ArcIMS for Ownership Identification and Service Differentiation of Electric Utility Lines John Seaver Course Project for GEOG 4550 Advanced GIS Department of Geography, University of North Texas Instructor: Dr. Pinliang Dong Fall 2006

2 Abstract This research project presents the development and implementation of a web based GIS system utilizing ArcIMS to identify ownership of electric utility lines and differentiate electric service areas. Often, different electric utility companies will have lines within the same vicinity, making ownership identification difficult and troublesome. The system developed here includes utility pole, power line, and substation data provided by one local rural electric cooperative to provide spatially correct location information. Positive field verification of ownership can be achieved with this system by utilizing information provided by the utility company. Emergency services can also benefit. Vehicles collide with utility poles daily, and emergency personnel often discover difficulty in determining ownership of the pole; therefore all utilities in the area are often called. This system can streamline the process for a police department, whereby accessing the IMS site can determine ownership of the pole and aid in the emergency situation. In order to help identify other utility companies within the study area, a paper map of the Grayson County Electric Service Boundaries from the Texas Public Utility Commission was scanned and digitized for use as a polygon shapefile within this project. Referencing this layer can narrow probable ownership of an unmapped utility line. A system such as this can be a valuable tool to local emergency services, commercial interests, the general public, and all utility companies. Introduction In this age of information, the pooling and sharing of data is becoming more common and more necessary. Web based GIS systems can provide valuable and accurate

3 information to aid commercial entities, utility companies, the general public, and emergency services. Mobile mapping is becoming more common among all industries, particularly emergency services, and a larger variety of data is becoming available to enhance mapping systems. Wanting to know what is where, and why is it there is a question common to all of us. In many areas multiple electric companies occupy a common service area making ownership identification of a utility line difficult to anyone unfamiliar with electric utility systems. During times of emergencies the unnecessary dispatching of all utility companies in the vicinity compounds this problem. Resources and time are wasted, and human lives often hang in the balance. Knowing which utility lines are owned by which companies would be invaluable to police, fire departments, paramedics, and emergency coordinators. Web based GIS systems designed to aid emergency services and provide public information are becoming more commonplace. Dong (2005) demonstrated how GIS and GPS could be integrated to create an emergency response system. He utilized data layers such as existing hydrants, buildings, etc. to enhance field reference points for the emergency responders using mobile GIS applications. Utility companies are realizing the value and importance of sharing data to enhance web based GIS systems. McAnally (2005) demonstrates how the city of Knoxville, Tennessee centralizes its data and provides it to the public. A power outage information system is made available to the public so that during outages vital information and current updates can be provided. Their website can be viewed at <

4 Utility companies also implement mobile GIS as an additional tool for their employees. CoServ Electric (2006) utilizes a mobile GIS system for lineworkers to access the latest updates to their power system. Equipment, control points, switch status, etc. can be confirmed with these mobile units. Any discrepancies found by the field personnel can be noted and quickly sent to the mapping editors for accurate updates. ArcIMS is being considered for implementation at Grayson-Collin Electric Cooperative (GCEC) in Van Alstyne, Texas. GCEC serves over 30,000 customers in Grayson, Collin, Cooke, Fannin, and Denton counties of north-central Texas. Tommy Nylec, electrical engineer for GCEC: We would like to allow our members, employees, other utilities and government agencies to be able to access our map and its data to varying levels of accessibility. We hope that ArcIMS can provide this level of functionality. Study Area Grayson County in north-central Texas was chosen for implementation of this project. It is a mostly rural county beginning to experience some of the rapid growth common in the region. Seven different electric utilities serve various areas of the county. Some of the areas are exclusive to one company or another (single-certified), however many of the areas are dual or multi-certified per the Public Utility Commission (PUC) of Texas. Differentiating between the various power companies can be frustrating for anyone without access to a PUC map or without extensive knowledge in the electric utility industry. Grayson-Collin Electric Cooperative, a non-profit electric company based in Van Alstyne, Texas, serves several thousand customers within the county. GCEC agreed to

5 provide data from their Gordonville metering point. This metering point and associated lines and equipment are in the northwestern area of Grayson County and subject to several different combinations of certification boundaries (Figure 1). Figure 1 illustrates 5 different certification boundaries within a small area of Grayson County, Texas. Data and Methodology Data files provided by GCEC are in the form of ESRI shapefiles and are spatially correct. All data from GCEC has a projection of NAD 27 SPCS, North Central Texas This projection will be used for all subsequent data. The layers provided are utility

6 poles, overhead primary lines, overhead secondary lines, underground primary lines, underground secondary lines, and various equipment layers from their Gordonville metering point. The substations layer from their entire system was also provided. Because the attribute data for these layers contains information that is either confidential or irrelevant for this project, all attribute data is deleted with the exception of the name of the substations and pole tag numbers. The substation names are used for labeling purposes within the map document and pole tag numbers are used for tool tips to aid in field identification of individual utility poles. The pole tag numbers are readily visible on each utility pole. Differentiating between primary and secondary lines for the general public was deemed unnecessary, only the spatial information is important. Therefore, both types of overhead lines (primary and secondary) are merged into one layer, OH_Lines.shp. Likewise, underground primary and secondary lines are merged into one layer UG_ Lines.shp. Equipment such as transformers, regulators, capacitor banks, though provided, is also deemed unnecessary for this project and is not included in the map. Roads, streams, county boundary, and water bodies of Grayson County are obtained from the U.S. Bureau of the Census through ESRI s 2000 census TIGER/line data website. All four shapefiles are projected accordingly. The county boundary file is used to clip the OH_Lines.shp, UG_Lines.shp, poles, and substation layers. This was done because the substation data received was from GCEC s entire system, which also serves parts of Collin, Denton, Fannin, and Cooke Counties. The Gordonville circuit layers also exceed Grayson County, with parts of the line residing within Cooke County. The clip insures a compact and reasonable study area for this project.

7 The Texas PUC provides no digital files of electric boundaries. Only paper maps are available from them, therefore a polygon shapefile has to be created representing the various electric utility boundaries in Grayson County. The paper map provided was revised in August 1977; therefore some discrepancies exist between the number and location of roads in the county. Roads are sometimes used as dividing lines with regard to electric service area boundaries. The 48 x 54 paper map provided by the Texas PUC was scanned and saved as a jpeg file at a resolution of 600 dpi. The jpeg is then added to ArcMap and geo-referenced to the Grayson County road layer using ESRI s spatial analyst extension. Approximately 46 links were installed in this process; the file is then rectified to save the image for digitizing. Digitizing as a polygon shapefile is conducted and results in 36 different polygons, 17 of which are unique to the electric company(s) serving the individual areas. The file is saved as GraysonElecBound.shp (Figures 2 and 3).

8 Figure 2 illustrates the scanned PUC Electric Boundary for Grayson County to be used for creating a new polygon shapefile.

9 Figure 3 illustrates the polygon shapefile digitized from the paper PUC boundary map. 36 polygons comprise this shapefile of PUC electric boundaries of Grayson County. The eight layer files used for this project are now ready to be used in the first step of ArcIMS. Labeling, displaying, symbology, etc. are not necessary at this point. When the layers are imported into ArcIMS Author these qualities are not imported. ArcIMS Author is the first of three necessary steps in producing an ArcIMS website. ArcIMS Administrator is next, followed by ArcIMS Designer. Author is used to import the data layers, either feature or image. The result is an AXL file. This project included only feature data, therefore only a feature service will be implemented. ArcIMS

10 Administrator is used to create the feature service on the server. ArcIMS Designer is used to create and design the webpage for the service. The eight data layers are now added to ArcIMS Author. Symbology, labeling, level of display can now be adjusted to suit the designer. The options are very similar to those found in ArcMap. The layer names can be renamed for a user-friendly approach. The layer naming is not case sensitive, and spaces are allowed. Once the eight layers are adjusted accordingly, the file is saved in the ArcIMS AXL folder with an.axl extension (Figure 4). ArcIMS Administrator is now used to create the service, and ArcIMS Designer is employed to design the webpage. Figure 4 illustrates the final.axl file used for this project.

11 Results The system is now tested by field verification from selected sites within the study area. The intersection of Greer Road and Sandusky Road is a location where multiple utility lines exist. By using the query feature for Greer Road, the intersection is displayed on the webpage. All layers are displayed and GCEC s utility line can be seen along the north side of Sandusky Road and the east side of Greer Road. There is, however, another utility line present along the south side of Sandusky Road that is not displayed on the map. Because the Electric Company Boundaries polygon layer is displayed and labeled, the electric service boundary area can be identified as dual-certified between GCEC and TXU. The utility line on the south side of Sandusky can be verified as belonging to TXU (Figure 5). Figure 5

12 Another scenario was tested from the perspective of a developer. This developer is interested in purchasing 300 acres bounded on the south by Chisum Trail and on the east by Jewell Road. Prior to finalizing the purchase, utility companies need to be contacted. By utilizing the layers on this ArcIMS website, both the utility line and electric service area can be verified as that of GCEC s (Figure 6). Figure 6

13 The query tool is invaluable for a site such as this. The layer from which a query is desired is selected as the active layer, Electric Company Boundaries for this example. The query tool is selected and Utility as the field to query. GCEC is selected from the several possibilities. The result provides us with five service areas of single certification for GCEC within Grayson County (Figure 7). Figure 7 illustrates one of the five service areas exclusive to GCEC in Grayson County.

14 Conclusions A site such as this is invaluable to the public, emergency services, and utility companies. Law enforcement and emergency services can verify utility line ownership during times of emergency. This eliminates the contacting of all utility companies during an emergency, thus saving time and money for all concerned. An individual requiring electric service can now determine the proper electric company to contact. A real estate developer can benefit for the same reason. However, limitations do exist. Only data from GCEC s Gordonville metering point was included for this project. As with most electric companies, a grid system resulting in the connectivity of the company s entire system is common. A user viewing what appears to be a dead end from the Gordonville data might assume that GCEC s ownership ends at that point. Actually, many of the dead ends in this data are open switch points separating two substations. Therefore, all data from an electric company should be included in future web based applications to avoid possible confusion. Limitations also concern to the PUC electric boundary shapefile created for this project. The PUC only provides paper maps, and the one used in this project was an edition from August Digitizing from scanned images can never be perfect; consequently some boundaries displayed within here could have errors by several feet. Also, these boundaries were determined many decades ago. Streams, gullies, and roads were often used as boundaries that may have moved or are non-existent today. Finally, electric companies occasionally agree to encroachment into their territory by another electric utility company when practical. Therefore, these boundaries displayed here should not be viewed as concrete.

15 Confidential data such as customer information, equipment specifications, serial numbers, etc. were deleted from the GCEC feature attribute tables. Therefore, the level of information presented in this project would not be very useful to a lineworker or troubleshooter from GCEC. However, deletion of sensitive data is not altogether necessary. Authentication via user id and passwords could be implemented to allow varying levels of access to sensitive data, as the company deems appropriate. Acknowledgments The author wishes to thank his former co-workers at Grayson-Collin Electric Cooperative in Van Alstyne, Texas for their invaluable help and support. Special appreciation is extended to the management of GCEC, particularly Tommy Nylec and Bruce Stevens for their enthusiastic support of this project.

16 References CoServ Electric Texas Not-for-Profit Utility Goes Paperless with Mobile GIS. Last accessed December 10, Dong, P Development of a GIS/GPS Based Emergency Response System. Geomatica, 59 (4), ESRI. Census 2000 TIGER/Line Data. Last accessed December 10, McAnally, C Knoxville s Centralized System Provides GIS to Utility. Last accessed December 10, Public Utility Commission of Texas. Publications and Forms. Last accessed December 10, 2006.