Wisconsin Co-op Uses Satellite Technology Load Control

Oakdale Electric Cooperative serves more than 11,000 electric consumers in central Wisconsin. Among those 11,000, the agricultural customers who utilize irrigation systems are at times the most demanding. Oakdale needed a reliable communications system that could accurately monitor and report customer electricity use so the utility could institute a voluntary load-control program among high-demand irrigation customers. The solution would have to provide reports at 15-minute intervals, especially during peak demand periods.

Oakdale contracted with Power System Engineering (PSE) for help in developing a reliable solution and to assist in the overall deployment and data analysis. PSE is a consulting engineering firm that has been providing technology support to electric cooperatives for many years. PSE serves the cooperative market by evaluating communications technologies that support distribution automation including radio, telephone, cellular and satellite.

Scientific-Atlanta’s satellite communicator.
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Ultimately, the solution PSE recommended to Oakdale was to deploy Scientific-Atlanta Inc.’s Low Earth Orbit (LEO) FSC1000 fixed-site satellite communicator, using the ORBCOMM satellite communications network. Scientific-Atlanta Inc. supplies broadband and satellite communications systems and manufactures a range of ORBCOMM satellite communicators for fixed and mobile applications. Acting on PSE’s advice, Oakdale adopted the Scientific-Atlanta solution.

The Scientific-Atlanta solution allowed Oakdale to implement a voluntary load control program through which the utility offered irrigation customers a favorable rate and demand charge if they agreed to switch off their pumps during peak demand periods. This situation occurred several times during summer 1999 and allowed the participating customers to virtually eliminate their demand charges. Scientific-Atlanta, PSE and Oakdale plan to extend the program next year to offer two-way communications, allowing customers to control their own specific loads via a PC and the Internet.

“We were very pleased with the overall results of the program,” said Gary Robison, Oakdale’s key account manager. “Working closely with Scientific-Atlanta and PSE, we were able to monitor all of the sites during the critical irrigation season. As a direct result of the program, we were able to report a reduction in peak demand over last year, while other cooperatives in the region were experiencing increases of more than 10 percent due to the hot summer. This resulted in real savings to our customers.”

Thomas Asp, PSE project manager, said that LEO satellite communication is an excellent solution for a utility’s remote distribution automation applications. He says that the LEO system provides an economical, reliable two-way data communications service.

“We initially evaluated the Scientific-Atlanta system as part of a study we conducted for the National Rural Electric Cooperative Association (NRECA) Cooperative Research Network (CRN), which provides technology recommendations to its members,” Asp said. “The study concluded that for remote applications that are not time-critical, LEO satellite communications can be a valuable communication tool for an electric cooperative’s automation efforts and offers a number of advantages over other communication technologies.”

Jack Tassos, vice president of Scientific-Atlanta’s LEO Satellite Data Systems business, admits that the Oakdale project was a small one, but that it did enable the company to demonstrate the advantages of deploying satellite communications technology for monitoring remote utility assets. “Oakdale and PSE were quick to see the benefits that global satellite communications can bring to their customers,” Tassos said. “We look forward to working with them on the next phase of this project.”

Scientific-Atlanta’s FSC1000 satellite communicator is a fully integrated satellite terminal built into a single robust enclosure designed for easy installation with electric, gas or water meters. The communicators have a number of standard interfaces including RS232 and RS422 serial ports, digital discrete sense lines and control outputs in addition to a utility standard pulse counter that lets the unit interface with distributed utility assets.

The Oakdale communicators connect to standard commercial electric meters that send pulses reflecting continuous energy consumption. The communicator is programmed to store the pulse count in 15-minute intervals and to send the data, via the ORBCOMM satellite network, at the end of each day. The data is received at Scientific-Atlanta’s Network Management Center (NMC), located in Atlanta. The NMC, which is manned 24 hours a day, 7 days a week, processes the data into industry standard formats and forwards the information to Oakdale for integration into customer billing reports.

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