Improved Multi-Conductor Interactive Rejection for Current Measurement with Magnetic Sensors Array

Abstract

In power systems, the emerging high-performance magnetoresistive sensor has been increasingly applied in measurement, protection, fault identification, and many other scenarios because of its high sensitivity, small size, and high bandwidth. Current measurement is one of the essential areas where the magnetic effect of current allows magnetic field sensors array to restore information about the characteristics of the power system. Nevertheless, in the parallel multi-conductor current measurement scenarios, sensors usually get interactive interference from neighboring currents, which significantly affects the measurement accuracy. This paper proposes an improved method for interactive rejection. In the new method, the inferior current measurement is utilized to eliminate the interactive interference and update current estimation by emulating the magnetic field. Compared to the traditional method, the new method improves the accuracy without any hardware change. In the numerical simulation, the mean absolute error of 29 A caused by crosstalk is reduced to 0.00068 A in a 3000 A three-phase system. In the laboratory experiments, the proposed strategy significantly reduces the mean absolute error of the three phases by 26%, 74%, and 40%, respectively.