Originally Posted by
plunet
It's not just the transmission NG 275kV substation that had assumed redundancy, you also can't assume that there's no single points of failure in the DNO 66kV substation, and of course I assume there's a single buried cable between North Hyde and a handover DNO single substation on the Heathrow campus.
Probably plenty of single points of failure.
Significant stakeholders like BA should be asking hard questions of their hub airport operator HAL as they could have made electrical design choices on their own campus that would have mitigated this risk.
From North Hyde, there are two cables about 500m apart, feeding the Heathrow campus. Each cable can be fed by any of the three substations. I have a drawing, but am loathed to post a screenshot, because I shouldn't really have it!