Utility Blames Huge NYC Blackout on Backup System Failure - NBC Connecticut
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Utility Blames Huge NYC Blackout on Backup System Failure

A statement from the power company said that a relay protection system at a substation on West 65th Street did not work



    Con Edison Relay Protection System Caused NYC Blackout

    It was supposed to safeguard against widepsread power outages in the city, but instead that measure failed and led to 73,000 customers without power in Manhattan. Now some are asking, what's to prevent it from happening again? NBC 4 New York's Chris Glorioso reports.

    (Published Monday, July 15, 2019)

    The reason a large portion of midtown Manhattan and the Upper West Side suddenly went dark — and stayed that way for hours — is due to backup systems failing, according to Con Edison.

    A statement from the power company said that a relay protection system at a substation on West 65th Street did not work. “That system detects electrical faults and directs circuit breakers to isolate and de-energize those faults,” the statement read. “In this case, primary and backup relay systems did not isolate a faulted 13,000-volt distribution cable at West 64th Street and West End Avenue.”

    That failure led to a fault at the West 49th Street substation, which triggered the Saturday evening blackout that affected 73,000 customers, some of whom did not have power for up to five hours in the hot weather.

    Some people were left trapped in elevators, and subway stations in the area went dark, with trains left bypassing those stations. The MTA said that five trains were stuck during the blackout, with engineers able to pull one car into the station and crews got the riders out through the trains themselves. A total of 2,875 passengers were left stuck on subways on the A and D lines.

    Con Ed initially did not believe that the 13,000-volt cable fault was initially related to the blackout. It is not believed that it was an “initiating event,” which then led to those relay systems failing and the ensuing outage.

    In more familiar terms, the backup system can be related to a circuit breaker in a standard house. That breaker isolates a fault and cuts off power to a specific area instead of the entire house. Con Edison said the primary and backup relays failed, leading the extensive outage.

    The company said that more than half of the effected customers had power restored in less than three hours, and all had power restored within five hours. All but three Broadway theaters had to cancel shows for the evening, and StubHub has offered $500,000 in refunds for canceled events. A Jennifer Lopez concert at Madison Square Garden was cut short as well.

    “We determined that the outage was not caused by transmission equipment. Further analysis identified the issues with the relay protection system,” Con Edison’s statement read. “We have restored our system to its normal state to continue providing our customers with the high level of reliability they expect and deserve. Our analysis of data and testing of the relay protection equipment is continuing, and will provide more insight into why the system, and its multiple redundancies, did not operate as designed.”

    New York City Mayor Bill De Blasio was forced to sidestep criticism from numerous quarters, including from fellow Democrat Gov. Cuomo, because he was in Iowa campaigning for his presidential bid while Manhattan was in the grips of a major power outage. A front-page New York Post editorial called for de Blasio's ouster.

    De Blasio said he took a four-hour car ride from Iowa to Chicago and got on the first available plane home.

    He insisted that the blackout response was well-managed with his remote supervision, and credited first responders with doing an “incredible job.”