"The sun erupted with one of the largest solar flares of this solar cycle on March 6, 2012 at 7PM EST. This flare was categorized as an X5.4, making it the second largest flare . . . since the sun’s activity segued into a period of relatively low activity called solar minimum in early 2007."
The grid did not fry, this time. More info re- the flare at NASA.