Sacrificial anode systems for underground metal structures

         When pipeline coating aging or quality is poor, for the protection of the current is too large, should carry on the line current test, determine level of protection potential current size and direction of current monitoring should focus more on the local leakage in place The first is a sacrificial anode system test items include soil resistivity anode grounding resistance of the anode open circuit potential The open circuit potential cathode

           Anode output current protection potential five test time interval for commissioning test shall be carried out in 15 days after the burial, management test should be conducted once a year, daily management should be conducted once a month protection potential tests, and to look at the ground facilities and maintenance of sacrificial anode in the underground metal structure existing in the management of some special problems 

           One is the spontaneous potential After pipeline in sacrificial anode cathodic protection, it is often hard to disconnect anode and measuring sp Therefore, we insist on pipelines buried underground after several days, on the whole pipeline sp test after completion of the sacrificial anode structure, auxiliary sample should be used to test the sp Another kind is the anode buried can't immediately after work This is also a common problem after the anode is buried in the ground, the open circuit potential is normal, and no current output. This is mainly caused by the drying of the anode filling material. It can be judged by measuring the anode grounding resistance, which may not be measured or very large