Power attributes are required

Power attributes (hertz, voltage, ac) used by EnergyInterop in the ramp schedule are required, however, these attributes would be known (or assumed) in any specific grid. The only instance where this information might be required, is those few locations where grid equipment from the two major vendors exist, e.g. Japan, where there is both the 50 hz grid and the 60 hz grid.

Recommend making these attributes optional.