Desenvolvimento de antenas de microfita para detecção de descargas parciais.

Abstract

This work presents the development of a circular microstrip antenna for the detection of partial discharges in power transformers. For this purpose, the truncated ground plane and slotted plane bandwidth enhancement techniques were used. In addition, aiming the achivement of an optmized structure in performance and size, computational simulations with several combinations of the studied antennas dimensional parameters were perfor- med. In order to verify if the developed antenna reach the prerequisites (bandwidth and gain) for the practical application in the detection of partial discharges, the optimized antena was built and subjected to preliminary tests in the anechoic chamber available on the Laboratory of Metrology of the Federal University of Campina Grande (UFCG), in Paraíba. Lastly, the antenna sensitivity of detection was verified by means of com- parative tests with the standard IEC 60270 method established for the measurement of partial discharges. For this purpose, the antenna and the IEC 60270 method were ap- plied simultaneously in a partial discharge generator arrangement, composed by an oil cell with tip–plane and plane–plane electrodes configurations, mounted in the High Voltage Laboratory of UFCG. The developed antenna presented good sensitivity results in the detection of partial discharges, detecting apparent charge values higher than 30 pC and presenting an average gain greater than 2 dB for the range of operation reached. The results obtained from this work attested the developed antenna potential, and can be used as base technology for the development of an UHF sensor for the detection of partial discharges in power transformers.