Tens of thousands of homes were left without power on Sunday just moments after the demolition of the Didcot power station.
Up to 49,000 homes in towns and villages across a wide area were blacked out when explosives were detonated to send shock waves through the 375ft tall towers, which crumbled and collapsed in huge clouds of rubble and dust at 7am.
An electricity pylon near the site was seen on fire after the blast.
According to reports from the scene, where crowds of spectators had gathered to film the blast, a drone may have hit a power line, causing a fire.
However, other witnesses said debris from the explosion may have caused the incident, at Sutton Courtenay.
A sub-station which serves Didcot and Abingdon, as well as Wantage, Wallingford and parts of the Chilterns blew. In the chaos, traffic lights went out and cafes were having to turn away hungry spectators.
The power was restored by 8.20am. Scottish and Southern Electricity initially insisted that the power-cut was unrelated to the demolition but said later the two were "probably linked".
SSEN added that an investigation is now underway into the cause of the incident.
Video circulating on social media showed an electricity pylon going up in flames and people who were gathered to watch the explosion running away.
They had been there to witness engineers blow up the three remaining 'death towers' where four workers were killed at Didcot in 2016.
Ken Cresswell, 57, John Shaw, 61, Michael Collings, 53, and Christopher Huxtable, 34, died in the major incident in February 2016.
The coal-fired station, commissioned in 1968, was turned off in 2013 after 43 years in service and owners RWE Npower had planned to clear the site by the end of 2017, but its plans were delayed when the site's boiler house collapsed, killing the four workers.
RWE said it had planned today's demolition over several months with its contractor Brown and Mason, liaising with the relevant local authorities. A plea went out to sightseers not to take selfies when the towers were blown up.
Owners RWE said they would "actively discourage all forms of public participation" amid fears that spectators would scramble for vantage points to take morbid selfies. They begged people to show some respect for the dead and not to gather and gawp.
In the February 2016 tragedy, four men died when a large section of the boiler house collapsed while the building was being prepared for demolition.
One was quickly found but the other three were listed as missing because it wsas too unsafe to search for them in the disaster area.
What remained of the boiler house was demolished in a controlled explosion in July 2016. The bodies of the three missing men were still in the remains at that time but were later found.
In 2003, Country Life readers voted the landmark Britain's third worst eyesore, but others have found the structures to be a source of inspiration for poetry.
The 2,000 megawatt (MW) station operated until 2013, when RWE Power moved to decommission it when new EU reduced emissions rules were brought in.
SSEN said in a statement: “Shortly after 7am this morning, SSEN received reports of damage to its network at Sutton Courtenay, following the demolition of the nearby Didcot Power Station. SSEN engineers attended site to make the situation safe and power was fully restored to the 40,000 customers affected by 8.20am.
“An investigation is underway as to the cause of the incident and SSEN is working with all relevant authorities. Further details will be shared once they are known.”