National Grid's Director of Operations, Duncan Burt, told the BBC on Saturday that its systems "worked well" after the "incredibly rare event" of two power stations disconnecting, Xinhua reported.
He said he did not believe that a cyber-attack or unpredictable wind power generation were to blame.
Meanwhile, regulator Ofgem has demanded an "urgent detailed report" into what went wrong.
It said it could take enforcement action, including a fine, after train passengers were stranded, traffic lights failed to work and thousands of homes lost power during the blackout.
An energy department spokesperson said National Grid must "urgently review" what happened and that it was awaiting its report.
Train passengers are facing further delays Saturday as severe downpours compounded travel chaos sparked by a major power cut in England and Wales on Friday.
The West Coast Main Line between Scotland and England was closed on Saturday due to flooding on the tracks between Carlisle and Lockerbie, according to Network Rail Scotland.