Failure Analyses on a Flexible Anode Cathodic Protection System in a Station.

Abstract

Flexible anodes are a common form of anode ground bed for the cathodic protection of buried pipes in station areas, especially in new stations. In most cases, flexible anode ground beds could obtain uniform potential distribution and good protection. However, in the process of operation, there are also failure conditions such as anode body or cable breakage, electronic shorting between anode and pipes and other situations, resulting in poor protection. How to troubleshoot failures has become a difficult problem restricting the application of flexible anodes in actual production. In this paper, the failures of a flexible anode cathodic protection system in a station were assessed and analyzed in detail. The main reasons for the failures were the electronic shorting between the flexible anode and buried pipe in local area and the breaking of a partial flexible anode. The troubleshooting methods for two kinds of failures were explored. By measuring the potentials of both the flexible anode and pipes in different areas and the excavation test, the location of electronic shoring was determined. And through measuring the grounding resistance of the flexible anode and excavation test, the breaking location of the flexible anode was found. By repairing the failure sites, the failed system was restored to normal, which could provide guidance for the failure analyses of the flexible anode cathodic protection system.