Diagnosis and assessment of remaining useful life in cable system in Colombia

TECNALIA was the successful bidder in an international tender launched by the Colombian electricity company, Empresas Públicas de Medellín (EPM), which consisted of the diagnosis and assessment of the end of life of the 230 kV cable system installed at the Porce 2 Hydraulic Power Plant, in Antioquia ,intended for the evacuation and discharge of the energy generated at this power plant to the transport network.

The Project included the evaluation of the state of the cables after almost two decades in service through the on-site performance of electrical tests, as well as the determination of the remaining useful life.

The electrical tests included the performance of a voltage withstand test on the main insulation of the cables using the Resonant System and the measurement of partial discharges, both offline and online for 24 hours after being put back into service. The current induction on the earth system during operation was also measured.

For the study of remaining life, the specifications set out in diverse CIGRÉ documents were used as a reference to define and develop a new assessment methodology. On one hand, the history of the cable system was analysed, based on the record of events, repairs and replacements, equivalent hours and the operating system and maintenance and diagnostic programmes implemented. On the other hand, the facility was fully inspected, from the outdoor terminals to the power transformer terminals, including the whole route through a pedestrian tunnel. Areas exposed to damp, metal elements at risk of corrosion, cable securing flanges and bending curves in the layout of the cables were also inspected.  The results of the tests carried out previously were added to this.

The final Project Reports were passed on to the client, EPM, with a fully satisfory result and assessment, which opens the door for future collaboration.

Contact:

Aitor Kortajarena
Electrical lab_services Director
TECNALIA