The principle of the hybrid-optical direct current transducer is introduced. Aiming at the shortcomings of conventional transformer

a new design is adopted

which uses ohmic shunt as sensor

optical fiber to send digitized data

gets power for controlling unit at high potential terminal from optical source

and has the outputs in both analog and digital formats. The experiment results indicate this method is feasible. And it has good dynamic performance and advantages with size

weight and costs. It will be used for HVDC in the future.