Optical power supply is adopted gradually in high voltage electronic current transformer as a new method of power supply.This paper presents a scheme of optical power supply in ECT

proposes a drive method combined by laser power supply and serial communication.The driving and protecting circuit as well as automatic constant temperature control system of LD are given

and the model of MCU control system is set up.Finally

the design of the efficient optical-electric converting circuit at high voltage side is carried out.