Optical Micro-current Transducer for the Measurement of Corona Discharge Current Under High Voltage Environment

Measuring corona discharge current directly on the high voltage side is essential for the discharge mechanism research of test object. The corona discharge is so weak that the amplitude of the current is in the level of muA and its frequency ranges from DC to MHz. An optical micro-current transducer used for the measurement of this current is described in this paper based on an amplitude modulation principle. It uses a fiber optic link for data transmission from the remote module (high voltage side) to the local module (ground potential side) and a battery for supplying power to the electronic circuitry of the remote module at high voltage side. The uncertainty of the transducer is estimated to be less than 0.5% in ratio and its response frequency range is from DC to several MHz.