Substation equipment failure near Truro causes widespread power flickering in Cornwall

Following maintenance work at a National Grid substation located off the B3284 between Truro and Shortlanesend, Cornwall, an incident occurred after the network had been restored to normal working. A piece of plant failed, producing a bright flash that was reported by local residents as explosions and fireballs visible from as far away as Falmouth. The failure caused a dip in voltage across a wide area of Cornwall, resulting in flickering lights and brief power interruptions affecting thousands of properties from Bodmin to Penzance, including Truro city centre where some Christmas lights and shop lighting were briefly affected. No property appears to have lost power for more than a few seconds. National Grid confirmed the substation as the source of the disruption and stated that repair work resumed the following morning.

The failure occurred shortly after maintenance work at the substation had been completed and the network restored to normal working, with a piece of plant subsequently failing.

1. Equipment restored to service after maintenance should be closely monitored in the period immediately following restoration, as failures can occur even after work is apparently complete.
2. Visible incidents such as flashes or bangs at substations can cause public alarm and should be addressed with prompt, clear communication from the operator.
3. Voltage dips from localised equipment failures can propagate to affect very wide geographic areas, so operators should assess resilience of downstream customers to brief disturbances.

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