Método espectral para localização de múltiplas descargas parciais na parte dielétrica de bobinas de hidrogeradores

Abstract

A methodology based on spectral analysis is established for performing localization of multiple partial discharges in dielectric region of hydro-generators coils. This pinpointing of multiple discharges aims to provide means for performing preventive diagnosis of the insulating region of the referred coil. A computer model of the structure was conceived by using the finite-difference time-domain method (FDTD-3D) to numerically solve Maxwell’s equations, which is experimentally validated. The transient electric field associated with partial discharges that occur at different positions of the coil is calculated and its spectrum, after processing and statistical analysis, is used to perform the diagnosis. In approximately 90% of simulations, accurate estimates of simultaneous discharges location were obtained. Transient numerical results are in agreement with literatures measurements performed experimentally. A new method of injection of partial discharge signals was also developed in this work.