American Transmission Co. (ATC) provides electric transmission service for Michigan's Upper Peninsula, eastern Wisconsin and portions of Illinois through 9,440 miles (15,192 km) of high-voltage transmission lines and more than 500 substations. ATC's US$2.6 million phasor measurement unit (PMU) project, which received a $1.3 million federal grant, is expanding the collection of phasor data from 45 to 90 substations throughout its transmission system.

ATC has 85 PMUs in service, 18 of which are digital fault recorders (DFRs) with synchrophasor output enabled. ATC is installing stand-alone Schweitzer Engineering Laboratories PMUs at sites that do not currently have DFRs and upgrading existing ERLPhase and Mehta Tech DFRs to give them PMU functionality.

Data from 35 PMUs is being sent to Midwest ISO with plans to enable all data later. The last five Department of Energy-sponsored PMU sites will be completed in 2013. ATC's project is also using new phasor data concentrators from Cooper Power, and improved data collection and historian software from OSIsoft.

Ultimately, ATC will use synchrophasor monitoring to improve system reliability and restoration procedures. Wide-area monitoring, visualization and system control enables a more expansive view of the bulk transmission system while revealing dynamic operating details. ATC soon will have PMUs installed and providing data at all 345-kV substations and large generating stations.

Long term, Jim Kleitsch, ATC's operation lead, sees “the data becoming increasingly integrated with ATC's existing processes so that operations, planning, system protection and asset maintenance personnel can analyze the data to determine how the system is performing.”

Starting in 2014, ATC will shift from getting the data flowing to analysis of the data and implementation of changes based on the results. ATC plans to extend synchrophasor visibility outside its operational footprint by leveraging data that will be made available from other companies as well as from the Midwest ISO.

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