NStar power failure prompts campus outage

A power outage that affected much of Cambridge for two hours Monday afternoon prompted loss of power at the Institute.

A failure in a 115kv transmission line at the NStar substation on Putnam Avenue in Cambridgeport triggered a widespread city power outage beginning at 1:11 p.m. The Institute lost power instantly. Emergency backup generators kicked in 10 seconds later, providing emergency lighting to the main campus and, in larger buildings, ventilation. Power was fully restored to most of the campus by 3:20 p.m. and to the entire campus by 4 p.m., according to Peter Cooper, director of utilities for MIT.

This was the first power outage on campus since August 7, 1997, when an explosion in a manhole near Kendall Square killed an employee of the Cambridge Electric Co. (now NStar) and caused an evening-long outage.

Monday's transmisson line failure at NStar's Putnam Station interrupted the power source to the transformers, leaving much of Cambridge without power for about two hours. When that occurred, MIT's cogenerator pumped power back into Cambridge for a fraction of a second, causing the cogenerator's frequency to drop drastically and the unit to shut down almost instantly.

MIT gets most of its power from the campus cogenerator -- which produces about 20 of the campus's required 28 megawatts; the remainder comes from the Cambridge power grid.

"Our emergency plan used to be to drop off the Cambridge grid the instant it started losing power, but with the increased power requirements on campus, we've changed our emergency plan," explained Cooper. "Now we hang on to the grid and go down with it, then start our blackout restoration procedure. Normally, we could start picking up power within 20 minutes and have it fully restored within an hour."

But yesterday, the process of restarting the cogenerator had to proceed more slowly than usual. Repairs to the plant planned for October will remedy that in future, Cooper said. Yesterday, NStar's power was available before the MIT cogenerator and was used during the initial power restoration to campus. Power was fully restored to the campus at 3:50 p.m.

Topics: Campus services

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