It is probably for first time that three grids are collapsing simultaneously.
Northern grid failed for the second consecutive day on Tuesday while Eastern and North-eastern grids also collapsed this afternoon, leaving more than half of the country powerless.
Power secretary P Uma Shankar said that all essential loads have been brought back and some of them have been restored.
"We are working on that. In an hour, it (situation) would be restored," he said.
Asked about the reasons for the failure of grids, Shinde said some states are drawing electricity over and above their limits. "This was creating problems," he added.
"This morning only, I was told (by officials) that about 3,000 MW extra power has been over drawn from the Eastern Grid. We have given the direction to either stop it (overdrawal) or take action against them," the minister said.