Real and reactive power sensors based on fiber grating

This paper demonstrates an optical fiber sensor using a fiber Bragg grating (FBG) to measure real and reactive powers. The sensor head is based on FBG encapsulated in a metal cylinder embedded a magnetic material at measure point. The operating mechanism is the sensor can be attracted by the induced magnetic force created by the apparent power in the solenoid along only one radial direction and responds to an axial force on the magnetic rod attached to the round plate, creating an axial attraction on the FBG. Therefore, variations in attractive force cause center-wavelength variations in FBG. A phase detector circuit is used to measure the phase angle between voltage and current signals. The power factor can be obtained by the phase angle. Thus, the sensor can be used to measure real and reactive powers without the use of traditional power meter.