LONDON, Aug 20 (Reuters) - A blackout in Britain which left almost one million homes without power on Aug. 9 was the result of a lightning strike, the grid operator said in a preliminary report.
National Grid has said the power cuts were the result of a rare and unusual issue that led to the almost simultaneous loss of output from two generators.
“As generation would not be expected to trip off or de-load in response to a lightning strike, this appears to represent an extremely rare and unexpected event,” it said in the report for energy regulator Ofgem.
“These events resulted in an exceptional cumulative level of power loss greater than the level required to be secured by the Security Standards and as such a large frequency drop outside the normal range occurred,” it said.
A final, technical report is due by Sept. 6. (Reporting by Nina Chestney; editing by Jason Neely)