Looks like the behavior on this issue has regressed.
We should disallow 0.0 as a base power for components. Otherwise, you can get thoroughly confusing things like PSB issue Sienna-Platform/PowerSystemCaseBuilder.jl#174: get_reactive_power(comp) yields 0.0, but calling set_reactive_power!(comp, 0.0) then changes the reactive power to NaN.
Looks like the behavior on this issue has regressed.