Experimental study on operational reliability of a kind of all fiber-optic current transformer

Compared with other kinds of electronic instrument transformers, the All Fiber-Optic Current Transformer (FOCT) have the advantages of high accuracy, wide dynamic range, strong ability to resist electromagnetic interference environment, simple and flexible of installation. But because of the short-time application, the operation reliability of FOCT can´t be assessed base on the operational log we have now. According to this situation, the study on the structure and work environment had been done, in order to find the main environment parameter which affect on the aging of FOCT. Then the accelerated aging tests had been done on the components of a FOCT such as photo detector, optical source and optical phase modulator Then the mean time between failures (MTBF) of these components had been estimated base on the results of aging tests. Finally we can assess the operation reliability of FOCT. The results indicated that the MTBF of SLD light source is shorter than other Optical Components in the current transformer which was studied on. And dual-redundant design could be used to increase the MTBF of optical sensor parts. Thus the MTBF of this all-optical current transformer could satisfy the requirement of 30 years long-term stable operation of instrument transformers.