Application of Magnetic Sensors for Measurement of Current Phasors in Power Systems

Digital Instrument transformers play a vital role in digitization of electric power substations and power systems network The advances in magnetic sensors research offer more precise and accurate current measurement that can be useful for monitoring the state of the system and detecting faults and thus leading to more reliability and dependability. Anisotropic magnetoresistive (MR) sensor can be used to measure the AC current by sensing the magnetic field generated by a current carrying conductor. This can be achieved through contactless method which is less complex in installation and maintenance compared to 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 noninvasive AC current measurement. A detail analysis of calibration and validation is performed for two sensors and results of comparison of their performances based on a few factors such as distance from current source and insulation are described in this paper.