And then to think that's just the Northeast corner of Houston that didn't quite take the full blast of the storm. The South and Southwest are likely worse, we just don't have accurate public maps of the outage.
So that 480 miles or so is probably less than a fifth of the total repairs needed.
I got the impression that OP was referring to total deferred maintenance of transmission lines in the entire Texas grid. If it is only storm related, that that seems more ballpark-accurate.
So that 480 miles or so is probably less than a fifth of the total repairs needed.