Transient Performances Analysis and Experiment for Optical Current Transformer
For qualitatively investigating the influence of the optical current transformer (OCT) on the protective relays, transient performances of OCT were theoretically analyzed based on the signal processing method of amplitude detection of single optical path, and it was also proved simultaneously that the aperiodic component influences the OCT output. Relay test equipment generated the high short-circuited current, and simulated transients were caused by a short-circuit fault. Field fault recording data-based COMTRADE standard format was obtained and event representation software of relay test device was also employed to simulate single-phase-to-ground fault and phase-to-phase fault, respectively. Transient response waveforms in the laboratory measurements of standard reference current transformer (CT) and OCT were recorded and compared with the fault recorder in the field individually. Laboratory research and experience show that OCT can reproduce the transient signal of electric network more accurately than conventional CT. Measuring records were also obtained and evaluated to verify that the optical systems might be more suitable for replacing conventional CT. Furthermore, empirical results also confirm that OCT has better frequency response than conventional CT.
KeywordsFaraday Effect Transient Performance Current Transformer Verdet Constant Faraday Rotation Angle
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