The Research and Development Project called “R&D ANEEL - COPEL "PD-06491-0421/2016 – NEW TECHNOLOGIES TO INCREASE THE RELIABILITY AND USEFUL LIFE OF POWER TRANSFORMERS”, was carried out in collaboration between COPEL (Companhia Paranaense de Energia), UFSM (Universidade Federal de Santa Maria) and VEGOOR Tecnologia Aplicada. The main objective was to evaluate the effects of replacing Kraft paper with hybrid paper as a solid insulator in the active part of transformers.

The equipment used in this project was a three-phase step-up transformer manufactured in 1969, with 70 MVA power and voltages of 13.8/230 kV – voltage-free switch. The transformer underwent a complete technological upgrade carried out by WEG, with the replacement of all the Kraft paper coils with NOMEX 910® hybrid paper in the high voltage (HV) windings.

From a technological point of view, it is also important to highlight the following items:

- Exchanging mineral oil for vegetable insulating liquid aiming at maximum convergence with the principles of sustainability;

- Inclusion of a direct temperature measurement system by optical fiber with 16 sensors, for detailed monitoring of the internal thermal state of the equipment, enabling automation and differentiated controls, which decisively contribute to the greater longevity of the equipment.

The improvements made also made it possible to obtain a higher power transformer, making 73.6 MVA available to the system, instead of the 70 MVA prior to the technical improvement interventions implemented by WEG.

This transformer was reinstalled at the Governador Parigot de Souza Hydroelectric Plant, located in Antonina, state of Paraná, where it previously operated. In addition to increasing the reliability of the plant, it will have a more sustainable operation. The use of vegetable oil and hybrid paper contributes to reducing the environmental impact, also resulting in a direct reduction in costs during the installation of the equipment, such as in the characteristics of the oil containment element in case of leaks.