The fire sent thick black smoke pouring into the skies near the Seattle's iconic Space Needle.
A spokesman said the fire broke out in a capacitor bank at the substation at Sixth Avenue North and Thomas Street just before 10 a.m.
Workers at a nearby construction site said they heard a pop at the substation and then saw smoke about 10 minutes later. Firefighters responded to the scene and began dousing the blaze.
No one was injured.
Most buildings in Seattle Center lost electrical service in the aftermath of the fire. The monorail was shut down due to the power outage, but many buildings, including the Experience Music Project, were able to continue operating on back-up power.
Power was restored to the Seattle Center by 12:30 p.m. and the monorail was able to resume operation.
The cause of the fire remains under investigation.