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T&D World Magazine

Central Maine Power Begins Upgrades to Portland Underground Transmission Cables

Central Maine Power Co. (CMP), a subsidiary of Iberdrola USA, began work to replace 3 mi of electric transmission cables beneath the streets of downtown Portland. The $3 million project will ensure continued high quality service to residents and businesses in the city’s Old Port and Congress Street districts. The work will not interrupt service to customers, but it may cause some congestion at worksites on some streets.

“These cables link the substations serving the city’s commercial center,” said Joe Purington, CMP’s Direct of System Operations. “They’ve been in place for thirty-plus years, so we’re replacing them as a preventive measure to maintain reliability.”

Contractors for CMP will start by replacing two 34.5 kV transmission cables between substations on Union Street and Forest Avenue along a route that includes Union Street, Spring Street, Oak Street, Cumberland Avenue, and Forest Avenue. Later this fall, the work will shift to a 34.5 kV cable between the Union Street substation and a facility in South Portland that runs beneath Union Street, Fore Street, Cross Street, and Commercial Street. CMP expects to complete all of the cable replacements by the end of December.

CMP is also planning a major upgrade to the Union Street substation in 2013 that will include the installation of state-of-the-art integrated electronic controls and gas-insulated switchgear.

“We are building a stronger, smarter grid with the support of our parent company, Iberdrola USA,” says Purington. “We will invest nearly $500 million this year to improve our system, and our projects like this one in Portland and elsewhere are creating thousands of construction jobs, while ensuring long-term grid reliability and capacity for growth.”

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