Explosion at San Juan Power Plant in Puerto Rico knocked out power for thousands of people.

Image Credit: Twitter account David Begnaud
Late on Thursday, an explosion in San Juan power plant in Puerto Rico resulted in a blackout for 400,000 people which is more than 1 in 10 residents on the island. The explosion was believed to have been caused by a fire in an electrical substation. No casualties or injuries were reported.
The fire caused major blackouts across the entire island. The situation is under assessment and work is being done to restore the system.
LUMA Energy on Twitter.
Gov. Pedro Pierluisi said that they are doing their utmost effort to handle the emergency and bring back power to the citizens. Some said it was an explosion while others claim it was a fire. More details will be revealed later on as the investigation concludes its findings.
All the resources of the PR government are available to handle the emergency caused by the fire at the Monacillos substation in Río Piedras. Firefighters have already arrived on the scene to handle to the situation. As soon as [firefighters] confirm more details, we will let you know.
Gov. Pedro Pierluisi
According to the newspaper El Nuevo Dia, at a press conference with local media on Thursday, LUMA Energy CEO Wayne Stensby said that at the peak of the power outage, 800,000 people were affected.
It is interesting to note that the power station was earlier cyberattacked using a DDOS attack. The DDOS (Distributed Denial of Service) attack is a common attack by cybercriminals to overload the web traffic in an attempt to overwhelm it.
The DDoS attack was identified and has been issuing 2 million visits per second.
LUMA energy
Regardless of this, there seems to be no connection between the cyberattack and Thursday’s explosion, at least for now.