The long‐term temperature induced errors caused by fiber λ/4 wave plate and the Verdet constant of sensing fiber in the all fiber current transformer (FOCT) are theoretically analyzed. A temperature related response of fiber λ/4 wave plate is adopted to compensate for the change caused by temperature related Verdet constant through choosing appropriate initial phase retardation of the λ/4 wave plate. The experimental results show high temperature‐cycle accuracy in this kind of FOCT with relative error within 0.6%.
In order to improve measurement accuracy of all fiber-optical current transformer (FOCT), an improved demodulation algorithm was proposed for a sine modulation. The formula for effective phase modulation depth (EPMD) was firstly presented, and three kinds of potential external disturbance in EPMD were analyzed. To overcome the current measurement error induced by these EPMD disturbances, we put forward an improved algorithm for time-dependent measurement of EPMD by second- and fourth-order harmonic component of optoelectronic signal. A simulation experiment in different disturbance intensity were carried out, and the results showed that when measured current is between 200A~1500A,the proposed algorithm can enhance the current measurement accuracy by over 30 times than the conventional algorithm, and measurement relative deviation can be maintained below 0.2% if the disturbance intensity is below 5%.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.