Microcontroller Based Active and Reactive Power Measurement

The work presented in this paper introduces a simple method for the measurement of active and reactive power digitally using microcontroller. Three signal values are generated, the first is proportional to the peak value (Vm) of the line voltage v(t), the second and third signals are proportional to the instantaneous values of the line current i(t) at the instants of v(t)=0 and v(t)=Vm, i.e. Imsino and Imcoso respectively, where Im is the peak value of the line current and o is the phase angle. These signals are inserted in to PIC16F877A by means of analog circuit. The active and reactive power are calculated by the algorithm written on the PIC16F877A. The calculated values by multiplications and digitization will provide a realizable and displayable form on LCD screen.