Three-Phase Busbar Current Transducer

Abstract

A true three-phase 1000 A busbar current transducer is based on six micro-fluxgate sensors. Instead of using three independent single-phase current transducers, we use the full information from each sensor. Two TI DRV425 microfluxgate sensors are inserted into a hole drilled in each busbar. Our method of data processing is optimized to compensate the crosstalk between the three phases and external fields and gradients up to second order. The crosstalk error between the phases was 0.23% or smaller. The suppression of field from an external current at a distance of 10 cm is improved by a factor of 25 to 150. Our transducer has compact size, high temperature offset stability of 8.5 mA/°C, high current range up to 1000 A, low power consumption, and linearity of 0.1%. The results from a three-dimensional finite-element model and analytical computations confirm the measurements