Análise da sensibilidade de acopladores direcionais microstrip na medição de descargas parciais em uma bobina de hidrogerador.

Abstract

In this work is realized a study based on experimental data, for analyzing the sensitivity microstrip directional couplers as sensors for measuring partial discharges in a hydro generator coil. To do so, four microstrip directional couplers were fabricated and through laboratory tests, we evaluated the applicability of these couplers for detecting electromagnetic pulses originating from partial discharges. In order to validate the measurements obtained by the partial discharges coupler better sensitivity, we used two sensors: a high frequency current transformer (HFCT) and a coupling capacitor 1000 pF. Data acquisition was performed with a digital oscilloscope four channels and data processing with the Matlab® software. The evaluation of the measurements obtained in the experiments was performed by the signal-to-noise ratio (SNR), the number of detected pulses counting and checking of the patterns plotted against the applied voltage, known method PRPD (Phase Resolved Partial Discharge). The results obtained in our laboratory demonstrated that the microstrip directional coupler proposed can be applied as a sensor for measuring partial discharges in a hydro generator coil. The same consists of a viable solution, with low manufacturing cost and a great sensitivity. However, to validate the application of the proposed sensor, a further study is still needed, considering all the implications of his installation in a real hydro generator, as well as the environment in which will be inserted.