Non-invasive Magnetic Sensors for Measurement of Current Phasors in Power Systems: Calibration and Validation

Real-time current monitoring is essential for precisely monitoring the state of power grid and also for detecting faults leading to more reliability and dependability. The advances in magnetic sensors research offer accuracy in measurement systems at less complexity in installation and maintenance with less cost. Anisotropic magnetoresistive (MR) sensor can be used to measure the AC current by sensing the magnetic field generated by the current carrying conductor. This can be achieved without touching the conductor or surrounding the sensor like conventional current transformers. This paper describes a novel method of current phasor measurement with the help of a low-cost, broadband and high-sensitivity Tunneling Magnetoresistance (TMR) sensor for AC current measurement. Based on the measurements from experiment for single phase, a detail analysis for calibration and validation of the sensor is performed. The accuracy in measurement is achieved by applying various conditions such as varying distances from the conductor and frequencies from 60Hz to fifth harmonic. Satisfactory results are obtained and are presented in this paper.