Replacing current transformers with power current microsensors based on hall ICs without iron cores

摘要

Current transformers (CTs) are adopted in power systems to measure magnitudes of currents for metering and fault protection. Since power system fault currents contain large direct current offsets, they can saturate the iron cores of the current transformers. This saturation phenomenon in iron cores will cause the protective system to make false responses. Furthermore, bulky volume of CTs also imposes restriction on their other applications. Hall integrated circuits (ICs) have high sensitivity and quick response time, and can measure a wide range of magnetic fields. Due to these attributes, this research designs a power current microsensor based on a Hall IC without an iron core. The applying Hall IC measures the magnetic field generated by a power cable and subsequently, the electric current flowing in the electric conducting cable. A measurement framework is designed and implemented to compare a series of waveforms obtained by the Hall IC with those measured by a traditional CT. This study assesses the feasibility of replacing traditional CTs with power current microsensors based on Hall ICs.