This model compares two resistive loads. Model R
consumes or produces a variable amount of power, while model
R1 consumes a fixed power.
At time t=0 R and R1 consumes
the same amount of power while at t=1 R
produces the same power consumed by R1.
P_nominal as this parameter is
disabled and assigned a value in the initial equation
section. This is for issue
426.