The original ground electrode of the Madeira River HVDC transmission system, bipole 2, was discarded due to the risk of saturation of the transformers in the Converter Substation of Porto Velho, located 15 km away, during the monopolar operation with ground return. After an extensive geophysical survey, a new site was selected, 40 km from the converter substation. For the confirmation of the new site, it was built in the central area of the site, a single-well 47 m deep test electrode, interconnected to the original 15 km electrode line by an additional 40 km long temporary line. A new electrode was then designed. This paper summarizes the test electrode procedure and the activities developed for the new electrode commissioning after its construction, which can be divided into two phases–pre-commissioning and commissioning. The electrode pre-commissioning was performed before its energization for the evaluation of the integrity of its components. The commissioning tests started with electrode energization, employing the electrode line, and an unbalanced bipole operation, which allowed the evaluation of its electrical performance. However, the main objective of the paper is the evaluation of the electrode resistance, which is an essential HVDC electrode parameter.

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My sincere thanks to my supervisor, Prof. Dr. Sueli Yoshinaga Pereira (UNICAMP), who accepted the challenge of guiding me along such a different path from my original formation;  to the Institute of Geosciences of the University of Campinas (IG-Unicamp), for the opportunity of developing this thesis, and to the lecturers who introduced me to the world of the Geosciences, particularly to Prof. Dr. Elson Paiva Oliveira, who was my first lecturer at IG-Unicamp;  to Prof. Antonio Padilha (INPE), also my lecturer, for the support to this research;  to Prof. Dr. José Antonio Jardini (USP), who gave to me the opportunity of developing a Research Project with FDTE (USP) and Eletronorte, concerning the application of geosciences knowledge for the project of HVDC grounding electrodes (2016-2017);  to Eng. Paulo Cesar Esmeraldo (XRTE) and Eng. John Grahan (State Grid), who respectively, indicated my name to develop electrode designs for the Ethiopia-Kenya (Africa) and Belo Monte (Brazil) HVDC projects;  to Eng. Daniel Kovarsky, who, back in 1985, introduced me to HVDC grounding electrode design, for the Itaipu HVDC project, and to Eng. Per Granstrom (ABB), who, in 2010, brought me back to this kind of project in the Rio Madeira, bipole 1, HVDC system;  to my parents Maria de Jesus B. da F. Freire and Paulo Edmundo Lisboa Freire (in memoriam) who gave to me the best education;  to my wife Solange Maria Trainotti, for the invaluable support along all the years devoted to this research, without which I would not have been able to complete this thesis. to my daughter Clara Werneck Freire and son Theo Trainotti Freire, to whom I hope this thesis is an example of how dreams can be achieved with commitment."Scientific knowledge is a body of statements of varying degrees of certaintysome most unsure, some nearly sure, but none absolutely certain."