By Maria Rocha-Buschel
Con Edison announced last Monday that the cause of a blackout affecting more than 70,000 residents in Manhattan on Saturday, July 13 was due to a malfunction at the West 65th Street substation.
The outage, which occurred at 6:47 p.m., affected customers from West 30th Street to West 72nd Street between Fifth Avenue and the Hudson River. The six electrical networks that were affected were back in service shortly before midnight on Sunday.
Con Edison said that their inspection of equipment and review of the system data found that the relay protection system at the substation didn’t operate as designed. The relay protection system is designed to detect electric faults and directs circuit breakers to isolate and de-energize the faults but in the case of the outage, the systems did not isolate a faulted 13,000-volt distribution cable at West End Avenue and West 64th Street.
The utility had initially ruled out the 13,000-volt cable fault as the cause, believing that it was unrelated to the transmission disturbance.