a well known formula,

 P=V*I

so,if power for an applience is constant,

  V*I=K(constant)

or,  V ∞1/I

e.g. P=1000W

if V=200V,it will take 5A current

if V=100V,I will be 10 A

therefore,for a device having constant power consumption,if we decrease voltage,it will take more current.and ultimately power consumption will be same.