Evaluación del aislamiento eléctrico a través de la respuesta en frecuencia a altos voltajes de impulso y de frecuencia industrial

Abstract

Electrical insulation is a fundamental part of the transmission and distribution systems and can be degraded for several reasons: aging, humidity, temperature, etc. For this reason, it is necessary to execute insulation diagnosis periodically. In this work a method of insulation evaluation is developed, through the frequency response obtained by applying low-frequency high voltage and standard impulse voltage. The main advantages, compared to conventional methods, are online diagnosis, low cost of implementation and analysis in the frequency domain. To validate it, the dissipation factors obtained by applying low-frequency high voltage are compared with those obtained by another method, based on the time domain. The latter uses a data acquisition device, and a standard capacitor with dissipation factor very close to zero. Once the method is validated, an impulse voltage generator is assembled with the elements available in the High Voltage Laboratory of the National Polytechnic School. The insulation is then evaluated by applying high impulse voltages. The noise of the measurements made in this stage is decreased with the help of the discrete wavelet transform.