No answer from NStar
By Patrick Mehr
Monday, June 25, 2012
When a plane crashes the traveling public is thankfully told more than “mechanical failure of unknown cause” (“Nstar blames oil leak for March blackout,” June 2). Extensive research is conducted to determine the root cause — the only way to minimize the chance of a similar accident. When massive power outages occur, the public deserves no less, especially since the company responsible for the outages is a monopoly. Well-designed, maintained and operated equipment does not just fail for no reason.
— Patrick Mehr, Lexington
The writer is director of Mass. Alliance for Municipal Electric Choice.
Nstar blames oil leak for March blackout
By Dave Wedge
Saturday, June 2, 2012
A massive blackout that plunged the Back Bay into darkness for days in March occurred when oil from a transformer ignited a blaze on a high voltage cable in an unforeseen “catastrophic” failure, Nstar officials reported yesterday.
The utility giant met a required June 1 deadline yesterday and filed a comprehensive, 76-page report with the city that included detailed explanations of the March 13 Scotia Street substation blaze that caused the blackout. The report also includes pictures of scorched wires, cables and electrical units, as well as recommendations on how to avoid a future catastrophe.
Dot Joyce, spokeswoman for Mayor Thomas M. Menino, said of the report: “The mayor will have his team review the materials but is very pleased (Nstar) was able to get it done on time so we can get on to the business of making sure these things don’t happen again.”
The report blames the blaze on the “unexpected release” of mineral oil from a “high voltage cable pothead termination” on the system. The “pothead” fractured, which was the likely ignition source of the fire, the report states.
The leak was caused by a “mechanical failure,” the cause of which Nstar officials reported is “unknown.”
While the blaze knocked out both transformers in the Scotia Street substation, Nstar officials said the “power control and protection system operated properly in response to the faults on the network.”
“Nstar meets, or exceeds, standards of good industry practice in the operation and maintenance of its Scotia Street substation,” the report states.
The same substation had another failure last month that knocked out power to thousands of customers in the Back Bay for an hour. That failure was blamed on a battery that failed as crews were repairing damage from the March fire.
Menino and the City Council have expressed frustration with Nstar over the outages and raised concerns that its transformers are not inspected by any government agency.
Among the report’s recommendations are periodic fire protection system reviews, installing a new “oil containment system,” and developing a “long term strategy” to replace faulty potheads.