(Reuters) - A lightning strike on a transmission circuit and power plant trips on Aug. 9 led to 1.1 million homes in Britain sufferinga power outage, National Grid informed Britain's energy regulator in its final report on Tuesday.
The report said security standards should be reviewed to see it was appropriate to take steps to improve the system's resilience.
The update was published in a final report to Ofgem by the company, explaining the circumstances surrounding a blackout that cut power and caused transport disruptions.
National Grid had said in a preliminary report on Aug. 20 that a lightning strike caused the blackout and also led to the almost simultaneous loss of output from two generators.
(Reporting by Muvija M and Noor Zainab Hussain in Bengaluru, editing by Louise Heavens)