Optimisation and Control of Cathodic Protection Systems 

ErnestosmallWeb.jpgThe PhD viva of Ernesto Santana Diaz has recently taken place at the Wessex Institute of Technology on his research on 'Optimisation and Control of Cathodic Protection Systems'. This research was carried out in association with the BEASY company within the Industrial Division of Wessex Institute, under the direction of Dr Robert Adey. The external examiner of the thesis was Prof Luiz Wrobel from Brunel University, with Dr Viktor Popov, head of Environmental and Fluid Mechanics Division at Wessex Institute, acting as the internal examiner. Both examiners were impressed with the content of the thesis and the presentation that was made by Ernesto.

Ernesto developed a new method for optimum design of ICCP systems which bind the boundary element models of the corrosion process with optimisation techniques. The software which has been developed will allow ICCP systems to be designed and optimised automatically in order to facilitate the study of cathodic protection systems.

The optimisation software attempts to find the best solution by imposing conditions in which the position of the anodes and corresponding currents are adjusted to satisfy pre-defined objectives.

In certain cases the anodes were fixed but in others they were allowed to move within a pre-defined search area. The procedure to carry out these movements in a reliable way was developed which enabled the anodes to be tuned to give their best performance for the criteria defined.

It is also possible to create entirely new designs by making modifications to existing designs. This technique can be applied to underground structures, pipelines, offshore structures, vessels etc. A number of different problems were used to assess the performance of the software by computing:

  •      The minimum number of anodes, their position and the current necessary to protect damaged areas.
  •     The current and position of the anodes to obtain a homogenous distribution of potential on the required surface.
  •     The current required and position of the anodes to minimise the UEP or to emulate another UEP signature.
  •     The current required and position of the anodes to reduce the influence of the new structure in its surroundings.
In addition to the design process this technique was also used to identify damaged areas by using data from the surface of the structure and measurements taken of the associated electric field.