Research On Key Technology Of Full Optical Fiber Current Transducer

Compared with traditional electromagnetic current transformer, full optical fiber currenttransformer has many advantages: no magnetic saturation, realization of transient protection,excellent insulation, strong anti interference capability, and so on. So it is taked more andmore attention. State Grid" Twelfth Five-Year Plan" put forward the full optical fiber currenttransformer as a key technology and equipment, and finished it between the time. Sometechnical problems that exist in all-optical current transformer at present were stduied, fromthe implementation of the system, analysis of wave plate error and compensation methods,analysis of the sensing ring and compensation methods, to the scheme of modulationdemodulation and signal processing circuit design. Main tasks are as follows:1. A detailed analysis about the theoretical of the optical fiber current transformer wasgived. Based on the current main scheme of some large companies at home, and abroadcurrent probelems of full optical fiber current transformer at home and abroad, the paperselected IN_LINE implementation based on Y waveguide as scheme, analyzed thetheoretical model in detail, gived the theoretical formula, established theoretical in deep infuture.2. A detailed study on wave plate error and compensation methods of the optical fibercurrent transformer was gived. Studied the theoretical of making wave plate in deep,established mathematical model of wave plate, analyzed the influence about scale factor bywave plate error in detail, studied compensation methods of wave plate error in deep.3. A detailed study on sensing ring error and compensation methods of the optical fibercurrent transformer was gived. Analyzed sensing ring’s Internal and external mechanism ofbirefringence, and established mathematical model of optic fiber current tranducer, studiedthe main error of sensing ring, looked for inhibition measures of sening ring error.4. The scheme of modulation and demodulation in loop-closed system were studied,established mathematical model of loop-colsed system, and analyzed system’s performance.analyzed preamplifier circuit’s error, analyzed the methods of selecting A/D and D/Aconverter and influence by phase modulator error in deep, looked for inhibition measures,analyzed algorithm of digital averaging filter. finally, established the experimental system ofoptical fiber current transformer, used the experimental results verified correctness ofsystem.