Two methods for improved measurements of reactive power and reactive energy insensitive to frequency variations

The paper describes the implementation of successive frequency-to-voltage and voltage-to-frequency conversion used to achieve a wideband frequency multiplication allowing reactive power and reactive energy measurements in the range of 40 Hz to 70 Hz of the input signal frequency. It also describes a phase shifting method which provides independence of the shifted signal of the capacitor value used in the phase shifter. This feature ensures long term stability and wide temperature operating range of the meter while retaining high accuracy