A new hybrid current sensor for high-voltage applications

This article presents a new hybrid electro-optic/inductive current sensor for metering and protective relaying applications. The sensor combines a Rogowski coil with a passive integrator located in the high-voltage environment. An integrated-optic Pockels cell (IOPC) having integrated electrodes provides optical isolation. Test results from 30 A to 30 kA show the sensor to be highly linear, exceeding 0.2% linearity standards. Temperature cycling tests show the ratio error to have a maximum value of 0.3% over the -30 to +70(degree)C range.