A POWER firm's engineers are working flat out over the Easter weekend to establish what triggered the most extensive blackouts in living memory.
SSE said its technical teams have already completed ground and aerial inspections of about 55 miles of overhead power lines in northern Scotland following Wednesday's cuts that affected 205,000 properties.
A full explanation as to why almost half the land mass of Scotland lost electrical power this week has yet to emerge.
Despite growing evidence that something hit the power lines, there is no sign of any obvious or permanent damage.
Homes and businesses from Highland Perthshire to Orkney and Moray to the Western Isles were affected. The worst-hit were off for four hours.
A spokeswoman said: "Although no obvious damage has been found to date, our teams will continue their technical analysis and close-up inspections of equipment in the area over the coming days and weeks if necessary. However, early indications point to what is known as a 'transient' fault, which although it leaves no obvious damage to a power line, will cause a brief interruption and is usually caused by an object striking the line. Examples could include debris, lightning, birds or a failure within a specific piece of equipment.
"Although our network is reliable 99.9% of the time, there are occasions when a fault may occur. When it does we will always restore power as safely and as quickly as possible while keeping customers updated on our progress. We would like to thank customers once again for their patience and apologise for any inconvenience caused while we restored electricity supplies to affected households' safely."
The inspections have been completed between the substations at Blackhillock near Keith and Knocknagael south of Inverness substations following what SSE described as a "rare and unexpected power failure in the north of Scotland" late on Wednesday evening.
Meanwhile, Inverness Clachnacuddin's Highland League fixture away to Fort William had to be abandoned with just 36 minutes played when the floodlights went out at 2-2.
In Inverness the power was down for only 20 minutes, but the leisure centre had to be closed and evacuated. The same happened at the Highland capital's Eden Court Theatre.
In Wester Ross, the acclaimed multi-instrumentalist duo Mairearad Green and Anna Massie were in the middle of their performance in Gairloch Community Hall when the lights went off.
However, Anna said that the 85-strong audience just moved closer to the stage and they carried on playing.