Noninvasive Current Sensor for Multicore Cables

Multicore cables are widely used in medium- and low-voltage electric power systems. Current measurement of individual conductors in such cables is especially useful for various advanced applications but technically difficult to implement. Since existing current sensing devices are designed for a single conductor, one has to break the cable enclosure or connector to access individual conductors for current measurement, which is practically infeasible. A noninvasive current sensor for multicore cables is proposed, designed, implemented, and verified in this paper. It is able to measure the magnetic field outside the cable using a sensor array and reversely calculate the currents on individual conductors. It is easy to install and adapt multiple cable specifications. Such a device is able to determine current phasors, perform harmonic analysis, and detect current disturbance with sufficient accuracy. The effectiveness of the proposed approach is validated by both laboratory experiment and field test.