GPS/GIS automates mobile gas leak detection
Bradley Grabowski Convergent Group, Senior Technical Consultant 6200 South Syracuse Way, Suite 200 Englewood, Colorado 80111
Background
The current leak detection vehicle system uses a Flame Ionization Unit (FIU) to detect methane gas in the atmosphere. The driver/technician receives a signal from the FIU that alerts them to the leak. Currently, there is not a device to record this data or any historical data about each driver’s daily leak routes. Handwritten documents regarding leaks found and handtraced maps are recorded for each day’s work. This system relies completely on the Leak Detection (LD) technician and the paper record trail. With the existing FIU, the LD vehicle leak surveys at low speeds of 3-5 mph, and the technician needs to constantly monitor the FIU readings. Also, the FIU has an 8+ second response delay from the point at which the methane sample is taken to the time that the sample is analyzed and the technician is alerted to a reading beyond the set threshold. The delay varies from vehicle to vehicle. At 3 mph, this is equivalent to 4.4 feet per second; from the point that the methane sample was gathered, a distance of 35.2 feet will be traveled before the FIU responds to an analyzed sample. The 35.2 feet does not take into account the added distance that is traveled for the technician to safely stop the vehicle after the technician is alerted. The LD technician now has to backtrack to the approximate location of the initial sampling point and localize the leak. A leak is graded after it is found. The leak grade determines the LD technician procedures and the process in which the leak paperwork is started. Grade ‘A’ leaks are called in to dispatch, and a Leak Sheet is started for each such leak in the dispatch center. The LD technician must remain at the leak site until an emergency repair crew arrives. If the grading is ‘B’ or ‘C’, the LD technician starts the Leak Sheet and turns it into the LD clerk at the end of the shift. The LD Clerk starts the data entry from information on the Leak Sheet. The leaks are then tracked and reports printed on a daily basis. Automated Leak Detection System With the use of the proposed ALDS, many of the tasks performed by the clerk and the LD technicians will be completed by the ALDS soilware and other integrated systems. The proposed system will integrate several pieces of technology that are available today. These include laptop/portable PCs, GPS, wireless data communications, dead reckoning system (ring laser gyro), and GIS. The proposed system will use an existing FIU-equipped LD vehicle. The major difference is that the proposed system will allow for the collection of data in real time and the storage of historical data about the technicians’ daily routes. The databases on the PCs contain the real-time GPS coordinates and real-time leak sampling data acquired from the FIU. The ALDS software is based on GeoLink, the GPS/GIS system developed by GeoResearch, Inc., and allows for the tracing of the GPS coordinates over a digital basemap produced from the GIS. The GPS tracing is displayed in real time on the display of the PC overlaying the digital maps, at the same time recording the GPS and leak data to the PC. This removes the manual task of tracing a map by hand from the technician. When a potential leak is found, the integrated system automatically highlights and records where the leak occurrence took place. An electronic leak form will be available for the technician to complete and send via wireless data communication to a central location. This data will be maintained as part of a permanent data store. The GPS data and leak detection data is uploaded to the GIS and is stored in defined data format as historical distribution system data. The electronic leak form data is uploaded to the Leaks On Construction Tracking System application. With the proposed data communication, the appropriate field crew can be immediately dispatched to the location of the leak. With the power of the GIS, forecasting of leak trends and detailed analysis can be completed in a graphical or tabular format. After enough cyclical data are collected, leak routes may easily be combined or altered depending on their cycle frequency and geographic location. When changing these cycles and routes, remember that all standard code requirements must still be met to satisfy the Office of Pipeline Safety (OPS), other regulator agencies, and the internal operations for the gas distribution company. The Pilot Like any other innovative technology project, the pilot was used to test the concept of integrating the numerous technologies that were proposed. An existing FIU, an existing GPS receiver with a DGPS receiver, an existing laptop PC 486-25, an AC/DC power converter, an existing LD vehicle, and a new piece of prototype technology called an Optical Methane Detector (OMD) was used in the pilot. The original pilot concept did not call for the use of the OMD, but the opportunity was there, and it was used. As detailed in the list of equipment, problems are already occurring. To have the FIU talk to the PC, an analog to digital interface needed to be established; however, there was not an 1/0 port on the FIU to talk to the PC. A port needed to be added to the FIU, tested, and software written to read the output by the PC and to put the data in an understandable format. The OMD also needed a communications link to the PC; although, this was easily established through the use of an existing RS422 communications port on the OMD. Again, the software needed to read the output from the OMD and the FIU. The PC being used did not have a cigarette lighter device available for power, so an AC/DC power converter was installed to power the PC and GPS receiver. Depending on how the converter was wired, a ground loop would occur and stop communications between both leak detection devices. Two final pieces were left to contend with—the GPS receiver and the DGPS receiver. The installation portion was adequate, but a few months into the pilot, the DGPS signal was disabled by MnDOT. So the 1-meter, real-time accuracy that was being achieved early in the pilot was gone. There are other DGPS alternatives, such as Accupoint and Omnistar; however, neither of which were used for the remainder of the pilot. The GPS portion of the pilot in general worked very well until the leaves on the trees appeared. The urban areas became a problem with the tree canopy blocking the GPS satellite signal, which in turn stopped the recording of data until satellite lock was regained. A data communications link was not used for the pilot, so data was transferred using diskettes. This was suitable for a one-vehicle pilot; for five vehicles, the diskette transfer was not an option. A pilot typically is used to prove concepts, to find weaknesses in the system, and to gather user input on the concept and the workings of the system. Although there were problems with the equipment and software integration and some GPS issues, the system performed well overall for a minimal amount of work and dollars. One of the major issues that was perceived during the pilot was that the technicians and the LD manager saw the pilot as a leak detection pilot and not as a data collection GIS integration pilot. Now that they are looking at the project differently, many new thoughts are arising regarding the use of the newly found data, including how the issues of the backpack leak detection crews were going to be addressed. The technology at the time of the pilot was not at a point where the backpack issues could be addressed at a reasonable cost. The Benefits The pilot project cost-benefit had been originally based solely on the fact that there would be a tremendous time savings on the part of the LD technicians and the LD clerk. Approximately one-third of the daily time would be saved due to the automation of mapping and electronic transfer of data to and from the LD vehicles. There would be no more hand coloring of maps and no more, or minimal, data entry by the LD clerk. Electronic Leak Sheets would be field originated, and the ability to dispatch repair crews in a more timely fashion with more accurate location description information would be seen as benefits. Using the power of GIS, the data collected during the LD surveys can now be easily analyzed. Forecasting of leaks can take place and differential calculations from previous data to current leak data can be made to help identifi the frequencies at which leak surveys could be done. Accurate time estimations for the routes can be established, and if the traffic flow information is in the GIS, better and more efficient routes can be established. Routes can be established on cyclical information as opposed to geographic areas. Through the better routing process not only can the time of the LD technician be put to better use, but there can be a large savings on vehicle maintenance, gasoline, and overall operating costs of the vehicles. This paragraph address issues that are somewhat intangible at this point, but you can see that with a little foresight, field data collection projects such as this will have a tremendous impact and benefit to the utility industry and help them establish themselves as world class organizations. Current and Future The leak detection process is back to the point where it was prior to the piloted Automated GPS/GIS Mobile Leak Detection System. The results from the pilot are being looked at in cooperation with the vendor of the GPS data collection software and hardware (GeoResearch, Inc.). New ideas have been established to address some of the issues found during the pilot phase. Even though the pilot system is not being used at this time, very good information came from the pilot that will be used to establish a new foundation for a 21 ‘t century leak management system. This will include the leak survey process, the analysis of data, and the improved efficiencies through the use of the GPS and GIS, data acquisition, and data management. The future leak detection system will be based on what was learned from the pilot project:
As mentioned earlier, backpacking has become an issue. Now that the technology that is needed is at an affordable cost, this additional requirement can be added to the project. An innovative approach will be used to address the backpacking issue. First, the weight that the backpacking LD technicians have to carry must be kept to a minimum. They already have the weight of the FIU (about 8 pounds). Now, add to this a GPS receiver, a DGPS receiver, a Personal Data Assistant (PDA), a spread spectrum radio, associated antennas, and a battery large enough to power everything but the FIU. Then, a device is needed to comfortably carry the additional equipment for a normal working day of 8 to 10 hours. What is different from the mobile system is the FIU does not interface to the PDA and the addition of the spread spectrum radio that has a transmit and receive distance of about 1 mile. To reduce the weight the technician carries, a PDA was the obvious choice for a computer, but there is a drawback to these types of devices. They have minimal memory capabilities to store data. The spread spectrum radio comes into play at this point. The radio will communicate to a laptop PC located in a vehicle within a mile of where the backpacking technicians are working. As the PDA’s memory becomes full, it will transmit the collected data to the vehicle and, in turn, the vehicle’s PC will transmit new data to the PDA that the LD technician will use for the new leak survey routes. Between the mobile and the backpacking systems, a field data collection foundation will be laid to support future field data collection projects. Obstacles All projects have obstacles. This is a sophisticated project that will lay the foundation for future projects, and there are many obstacles that have to be addressed. Executive stakeholders need to be established early on. Papers, such as this one, need to be used for this purpose, but also, the project must show that it is strategically aligned with the company’s mission and that the cost-benefit has a good IRR. Once the executive stakeholders are established, the front-line stakeholders need to be brought on board. This is done by using their input and approval to develop the project. There is a lot of technology used in this project; training and regular meetings need to take place early on with the users of the system to maintain their confidence in the project. Technical obstacles are always an issue; there were several mentioned early on, but in this project, wireless data communication of both tabular and digital map data is a stumbling block. The main reason is wireless data communications for the operations division within Minnegasco has not been standardized. Projects, like the leak detection project, will force the issue and help establish good wireless data communications in the company. The loss of the project manager is always an issue. A complex project of this size needs to be run by a team of experts. There should be a project manager to coordinate all disciplines, but all team members should be experts that understand not only their contribution, but the total project and all the technological pieces. The team should ensure that the project sponsors and stakeholders are constantly kept up-to-date with project status. This communication starts with acceptance by the stakeholders and sponsors of a well-defined project purpose, scope, and objectives document. The team then needs to apply strict project methodology to proceed with the project, collecting and reporting results against original objectives, acceptance criteria, and budgetary constraints. Lastly, scope creep. As the project progresses, those involved—whether they are sponsors, team members, or users—may want to add new capabilities to the system. Keep this in check. This is a large and sophisticated project, and the original scope needs to be contained to complete the project on time and within the original budget. Conclusion To bea21” century utility, gas and electric utilities need technological projects, such as this, to be brought to the table and completed to maintain a leading edge. This project does have that technological sophistication. This is needed to bring this company to the leading edge. It is a difficult project, but being number one is not easy. Executives must maintain complete support of the project and guarantee the resources needed to complete the project. In return, the project manager will meet the milestones. This is significant and shows the executives that the project team believes in the project and are willing to do what it takes to get the job done. The users have an opportunity to bring themselves and the company to the next level. They need to step up to the plate and use this technology to improve themselves and their utility. Good concepts will have problems. That is why pilot projects for this and similar projects are needed. Problems will arise, and the pilots will help filter these issues. In turn, these issues must be addressed for the full project implementation to be a success. GPS and GIS are not acronyms to be used lightly. These are powerful technologies that are a part of life in the utility industry. As executives, project managers, analysts, and users, one needs to use these powerful technologies to maintain a company’s life in the industry. This project and others like it are for the benefit of the company. The project may be a secret for ears outside the company, but not internally. Communicate the project throughout the company and make the project concept and project progress known. Other persons within the company may have had similar thoughts about portions of your project, and they may want or need to piggyback on those segments. Reuse good technology that the company has developed or purchased. Published monthly updates and casual informative meetings are always good for the project’s success. | ||
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