Evaluation of the Operative State of Power Capacitors of the Distribution System

The goal of this project was to evaluate the performance of the operative state of power capacitors installed in the substations of 13.8 - 24/34.5 kV and even 138 kV of an electric power company in Rio de Janeiro - Brazil. We intend here to present the developed methodology and to argue about the reached issues. We used the Partial Discharges (PD) measurement technique with the registration of acoustic signals in the ultrasound band. With capacitors tanks under potential, we implemented a special system isolated with an optical fiber. One of the main issues obtained in this work was the development of a simple and easy technique of measurement in the field (using ultrasonic piezoelectric sensors, a digital oscilloscope and a notebook), which made the evaluation of more than 300 capacitive units possible.