Thesis defense of Unai Garro Arrazola


Thesis defense of Unai Garro Arrazola


Thesis defense of Unai Garro Arrazola

Title of the thesis: “Methodology for the Accelerated Reliability Analysis and Prognosis of Underground Cables based on FPGA”. Obtained the SOBRESALIENTE qualification and the CUM LAUDE and DOCTOR INTERNACIONAL mentions.



  • Title of the thesis: “Methodology for the Accelerated Reliability Analysis and Prognosis of Underground Cables based on FPGA”.
  • Thesis directors: Eñaut Muxika Olasagasti, Jose Ignacio Aizpurua Unanue.
  • Court:
    • President: Brian G. Stewart (University of Strathclyde)
    • Vocal: Rafael Peña Alzola (University of Strathclyde)
    • Vocal: Xose M. Lopez Fernandez (Universidad de Vigo)
    • Vocal: Ian Paul Gilbert (Ormazabal Corporate Technology)
    • Secretary: Gonzalo Abad Biain (Mondragon Unibertsitatea)


Dependable electrical power distribution systems demand high reliability levels that cause increased maintenance costs to the utilities. Often, the extra costs are the result of unnecessary early maintenance procedures, which can be avoided by monitoring the equipment and predicting the future system evolution by means of statistical methods (prognostics).

The present thesis aims at designing adequate methods for predicting the future degradation evolution of high and medium voltage underground Cross-Linked Polyethylene (XLPE) cables within an electrical power distribution grid, and predicting their remaining useful life, in order to define an optimal maintenance sequence.

However, electric power distribution grids are large, components interact with each other, and they degrade with time and use. Solving such predictive statistics currently requires long numerical simulations that demand large computational resources and long simulation times even when using advanced parallel architectures. Often, approximate models are used in order to reduce the simulation time and the required resources.

In this context, Field Programmable Grid Arrays (FPGAs) can be employed to accelerate the simulation of these stochastic processes, but adapting the physics-based degradation models of underground cables for FPGA simulation can be complex. Accordingly, this thesis proposes an FPGA-based framework for the on-line monitoring and prognosis of the underground cables based on an electro-thermal degradation model that is adapted for its accelerated simulation in the programmable logic of an FPGA.