According to the company, an issue with its relay protection system—which should, in theory, trigger a circuit breaker should any equipment failures happen—led to the outage. “The relay protection system is designed with redundancies to provide high levels of reliability,” the company said in a statement. “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.”
Initially, the company said that a “significant electrical transmission disturbance” at Con Ed’s West 49th Street substation was the cause of the outage, with that issue likely triggering additional Con Ed substations across Manhattan to go dark. But according to its preliminary findings, the damaged cable at West 64th Street was the “initiating event,” and the outages were a result of the failure of those protective systems.
At its peak, the power outage left some 72,000 New Yorkers in the dark, with subways, Broadway shows, traffic lights, and stores all affected, The blackout started around 6:45 p.m. on Saturday night, and was resolved by midnight.
“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,” Con Ed said in a statement.
Lawmakers have blasted Con Ed for the blackout in the days since the blackout happened, with Gov. Andrew Cuomo repeatedly calling the incident “unacceptable.” On Fox5NY this morning, Cuomo said, “I’m going to do an independent investigation with power experts that we have in the state to find out exactly what happened and why and we’ll get it done as quickly as possible.”
The New York Times noted that Mayor Bill de Blasio (who missed the blackout while on a campaign stop in Iowa) and Sen. Chuck Schumer have also called for an independent investigation into Con Edison’s grip on NYC’s power grid.