I'm virtually positive this issue was different than one a person here experienced. Note the time (1 PM) among the other details. And according to a later article it was "one of the older streetcars (that) broke down on Saturday".
I was at the OMSI stop when the bad car came in, had a mechanic board and pulled forward to the tail track, having finished my visit to the rail museum opening and heading to the Architectural Heritage Center streetcar exhibit.
As evidenced on my YouTube channel, I happened to hear about the breakdown some people experienced and was in the area and went and filmed it (from afar next to the substation the maintenance guy was in).
In addition, others here reported on Twitter about the breakdown being north of where you were stranded.
And later (when I was at the Convention Center plaza) I saw the USA streetcar go by in service.
Lastly I'd like to note that in this comment I said "And I think it was a power system issue NOT related to that streetcar." As in I wasn't sure because I wasn't able to fully hear what was happening.