In the smart grid

current measurement is the key to relay protection

energy metering

monitoring and system analysis in the electric power system and the measurement accuracy and reliability are directly related to its safe

reliable and economical operation.This paper compares the performances of the electromagnetic current sensors and fiber-optic current sensors and introduces the measuring principles of 3kinds of major ones and points out their advantages and existing problems.Then

it summarizes their latest research status and advances at home and abroad.Finally

it forecasts the prospects of their applications and researches.