Analysis of Shielding Structure and Material of MVDC-Class Current Sensor for Securing Magnetic Field Immunity

The current sensor of medium voltage DC converter station is basically required to have accuracy and linearity, and it must be immunity to the severe electromagnetic environment in the converter station. This paper analyzed the shielding structure and shielding material to satisfy the magnetic field immunity of MVDC-class current sensors. In order to evaluate the shielding characteristics against external magnetic fields, the test conditions specified in KS C 9610-4-8, 9 were referenced. The magnetic field strength and magnetic flux density distribution inside the sensor part, which can affect the current measurement, were calculated through three-dimensional finite element analysis. The analysis results are expected to be useful reference data for shielding design of fluxgate type current sensors.