A sled of sacrificial anodes can be used to provide Cathodic Protection to structures. However sled design presents challenges to the CP engineer as experience (supported by fundamental electrical principles) has shown that:
- Anodes in groups do not deliver as much current as they would individually because of interference
- Connection cables have to be carefully designed to prevent attenuation impacting on the performance of the anodes
- The location has to be carefully chosen to avoid interference with nearby pipelines and structures
In this study a detailed three dimensional model was created of the anode sled, connection cables and the nearby structures. The model was used to determine the actual performance of the anode sled and the level of protection provided to the structure over its life.
Alternative locations of the sled and of anodes on the sled were used to assess interference with nearby structures and ensure adequate protection of the structure.
The CP designer was able to evaluate several alternative solutions and choose the one which:
- Adequately protected the structure without compromising the integrity of adjacent structures
- Gave best compromise between cost and performance