Pipeline &
Gas Journal
April issue 2000:
World’s Largest
Public Service Company of Colorado Completes AMR Installation
by Gerald Bonser, Manager of Measurement Technology and Services,
Public Service Company of Colorado, Denver
Inclement weather, overprotective landlords and large angry dogs—all these can make a meter reader’s job challenging at best and a nightmare at worst. Today in the Denver metro area, however, those threats are gone.
New technology has made the time-consuming job of manually reading meters one that can now quickly be done from the safe comfort of a van. Public Service Company of Colorado began a project to install new meter-reading technology in 1994 and completed the automated meter reading (AMR) in November 1998.
More than 800,000 electric meters and 700,000 gas meters in the Denver area are now fitted with devices that transmit meter readings using radio-frequency technology. In terms of number of meters, Public Service Company’s AMR system is currently the largest such system in the world.
Gas meters were retrofitted with the “encoder, receiver, transmitter” radio units (ERTs), and electric meters were either retrofitted or replaced with new meters containing ERTs. Every residential electric meter in the Denver area was then recalibrated to ensure accuracy.
With the new ERT meters, Public Service Company has achieved a remarkable monthly read success rate of 99.7 percent. This rate falls just short of 100 percent, because radio-frequency disruptions block an average of three readings out of a thousand.
Public Service Company researched the providers of this new radio-frequency technology and chose Spokane, WA-based Itron to supply the ERTs, which read a meter’s rotation 100 percent accurately. When a van drives by, it sends the ERT a signal that wakes it up, and it then transmits the meter reading to the van. Currently, Public Service Company is reading the meters in the Denver area with five vans and seven drivers. Before the retrofit, the company needed 185 meter readers to do the same job.
Only the Denver area’s three-phase electric meters of commercial customers have not been automated with ERTs, but a radio-frequency solution for those is now being tested. At the end of the project, only a small number of residential meters hadn’t been retrofitted, mostly due to problems in accessing those meters.
Public Service Company is currently running a pilot project to fit its distribution system in the Denver area with “fixed network devices” that will talk to the ERTs at any time. A fixed network would entail thousands of cell-control units (CCU) placed on utility poles around the metro area. Each CCU would cover the approximate area of a 1,000-foot circle, and such a network would allow for meter readings literally at a touch of a button.
A fixed network would eventually allow virtually all pertinent information about energy transmission to be accessed immediately at any time. It also would allow for real-time readings of all meters in the system. This means that load information would be gathered on an almost real time basis and used for system evaluation. Knowing how the distribution system reacts under various conditions results in better decisions regarding operation, and ultimately saves money. Identifying those parts of the system that may be reaching their capacity before a failure occurs would also save money. Well-timed reinforcements are essential in today’s business environment.
The increased granularity of meter reads afforded by the fixed network would also help in the gas transportation arena. There are times when it is important to not only know how much gas was used, but when it was used. ERTs, under a fixed network, could provide this information to gas management computers. The results would be displayed quickly enough to allow any necessary correction to usage and therefore avoid penalties.
The new ERT-fitted meters also have internal tamper-detection devices that indicate if customers attempting to change their meter readings have tampered with their meters. Besides providing accurate meter readings and detecting tampering, the meters also transmit a “last gasp” signal, which informs the company that an ERT is about to fail so maintenance crews can go out and replace it.
The new ERT-equipped meters have improved accuracy, eliminated estimated bills, stopped customer property intrusions, minimized safety problems, and provided cost savings features. It has proven to be a very successful effort. P&GJ
Gerald Bonser is Manager of Measurement Technology and Services for Public Service Company of Colorado. He has 32 years of experience and managed Public Service Company’s automated meter reading install project.