PRINCIPLE AND TECHNOLOGY OF DIGITAL ELECTRO OPTIC MEASUREMENT FOR POWER SYSTEM

The digital technology has almost been applied in all fields of the secondary system in the power system, and the control, metering and protection of power system are carried out on the basis of application softwares. To meet the need of renovation in secondary system, it is demanded to develop the new types of voltage and current transducers with low output level. After analyzing the problems being encountered by conventional CT and PT, a new approach, i.e., using low power and compact measuring system, is proposed. The principle and technique of Rogowski current transformer, magneto optic crystal current transducer, electro optic voltage transducer and digital measuring system are described. In this paper the experiences from on site trials abroad are presented. Theoretical analyses and on site trials show that the performance of digital optical electric measuring system is much better than that of conventional PT and CT.