May 7, 2004 By Merrill Douglas
Residents in search of high-speed Internet connections need look no further than the nearest electrical outlet. In what is said to be the first citywide service of its kind in the United States, Manassas is using its power grid to deliver broadband data service to local businesses and homes. As of early February, about 70 people were enrolled in the broadband over power lines (BPL) service.
"We have 600 or 700 more on a waiting list," said Allen Todd, director of Manassas Utilities, a city agency.
Officials at Manassas Utilities weren't thinking about Internet service when they started exploring technologies for carrying data over power lines -- they just wanted a reliable way to identify power outages in their distribution network.
Manassas Utilities was using technology to monitor its water plant, electrical substations and other major facilities, but systems to do the same for transformers on the power grid were expensive, Todd said.
Then the American Public Power Association (APPA) introduced city officials to Main.net, which develops, markets and sells complete power-line communications (PLC) systems to power utilities. This gave utilities the chance to use their existing power line grids as a commercial communication medium.
Ron Lunt, APPA's director of broadband services, said a visit with the company convinced him the technology was viable.
"We talked to Manassas to see if they'd be interested in deploying it and applying for a grant through our DEED [Demonstration of Energy-Efficient Developments] program, our R&D group," Lunt said, adding that APPA approached Manassas because the city was already looking for this sort of technology, and is close to Main.net's office and APPA's headquarters in Washington, D.C.
The technology looked good on paper, Todd said, so Manassas tried a pilot system that covered a small section of the city.
"Main.net provided the equipment, APPA provided the funds and we did the installation," he said.
Launched in May 2001, the system not only transmitted data from distribution circuits, but also provided Internet service to about 10 residential and commercial customers.
"To our surprise, it worked very well," said Todd, admitting his initial skepticism. "The reliability was good. We didn't have a unit fail. It was operating at a very good rate of speed and looked like it also gave us the monitoring we needed for the transformer outages."
Manassas added customer Internet connections because revenues from offering broadband service would give the city power-monitoring capabilities for free, he said.
The service also helped the city make better use of its fiber-optic ring, which it installed in the 1990s to replace leased phone lines. Since the fiber connects the city's traffic signal control system to all traffic lights, it offers extensive coverage.
"We own and operate our own power system," Todd said. "We own and operate our own fiber network. We were looking for a way to merge those two together, and this was one way to do it."
Power lines provide a convenient way to carry data between the backbone and subscribers' premises -- it gets expensive to run fiber into each house, and the city would have to dig up sidewalks, gutters, streets and back yards to run that fiber.
Since the power infrastructure already reaches into every building, the city could avoid those disruptions. Manassas also wouldn't have to shut off electrical service to start the data flowing, he said, and city workers already have the necessary skills to install and maintain the equipment.
Repeaters Boost Signal
Carrying broadband data on power lines is not simple because, unlike telephone or cable TV infrastructure, the power grid wasn't designed
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