Abstract: A method and/or apparatus for measuring current in a high voltage (HV) current carrier generates a low voltage signal proportional to the current in the HV carrier and applies this signal to an integrated-optic voltage sensor located in the HV environment adjacent to the HV current carrier to produce a modulated optical signal representative of the current being measured. The optical signal from the integrated-optic voltage sensor is conducted to a low voltage (LV) environment insulated from said HV environment and processed to provide a second electrical signal. One of the electrical signals is integrated so that an output signal of the required accuracy is available form the system.