Phase Angle Measurement Using A Pll : Along with lead/lag identification feature

Phase angle measurement between two AC waveform having same frequency is needed in various applications like 3-phase transformer connection,CT and PT installation,Power factor determination. Conventional phase angle meters are bulky and costly.A new method for measuring phase angle using a digital PLL is proposed with operating frequency range of 20Hz to 1kHz. This design also has lag/lead identification feature and is cost effective.The phase angle meter involves phase detection using PLL, frequency to voltage conversion, calibration and display.A regulated power supply and a phase shifter circuit are also designed to test the phase angle meter.A 3 1/2 digit LED display panel meter is used to display the final measured phase difference between two AC waveforms fed as input.