A Flicker Away From a Blackout

At 4:15 p.m. on May 27, the lights flickered across Ontario.

Subway cars in Toronto rolled to a stop while safety signals were reset. Pizza oven doors flew open on the ground floor of the city’s landmark CN Tower. Cement and steel plants paused while machinery was restarted. Tens of thousands of computers automatically shut down and rebooted.

Hydro One, the Toronto-based electric utility, quickly issued a press statement seeking to reassure the public that the utility’s “equipment protection worked as designed to isolate the fault.”

In fact, the situation was much more tenuous. The power blip involved an extremely rare, still unexplained failure of two protection systems, according to internal documents of the utility, reports to oversight agencies and eight engineers. The eight are part of a group that has been on strike since June 6. By their accounts, the failure brought the region’s power grid to the verge of a blackout like the one that struck on Aug. 14, 2003, plunging 50 million people in the United States and Canada into darkness.
The Washington Post