Heathrow ‘shutdown fault’ first found seven years ago

A POWER outage that led to the shutdown of Heathrow and the cancellation of more than 1,000 flights has been blamed on a fault detected seven years ago but never fixed.

- By Rosie Shead

A substation fire that triggered the incident on March 21 was caused by a maintenance failure at National Grid, according to a damning report from the National Energy System Operator.

Moisture entering an electric component “most likely” caused the fire, which started at the North Hyde substation in West London.

Disrupted

An “elevated moisture reading” was found in oil samples at the substation in July 2018 but action was not taken to replace electrical insulators known as bushings, Neso’s report said.

In 2022, a decision was made to “defer basic maintenance” at the substation, meaning the issue went “unaddressed”, it added.

The electricity outage led to 71,655 domestic and commercial customers losing power and loss of supply to part of Heathrow’s internal electrical distribution network.