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In order to improve the safety protection effect of the cathodic protection system, the cathodic protection system is tested regularly, and the problems existing in the cathodic protection system are found in time and dealt with in time. To take the necessary maintenance measures to improve the effect of the cathodic protection system, in order to achieve the effect of cathodic protection, extend the service life of the protective structure, to prevent the corrosion of metal pipes, cathodic protection has two forms, cathodic protection of sacrificial anode and cathodic protection of impressed current. To detect the effect of cathodic protection, find out the failure of cathodic protection measures in time, and take necessary remedial measures to improve the effect of pipeline cathodic protection. The way of system detection, according to different cathodic protection measures, the potential of each part is detected, and the operation of the cathodic protection system is evaluated by comparison.
Maintenance of cathodic protection of sacrificial anode
1, the daily maintenance of the protection of the pipeline sacrific anode is not much, in addition to the protection potential measurement according to the requirements of impressed current cathodic protection, test pile maintenance, insulation joint detection, grounding troubleshooting and other work, it is recommended to measure the parameters every year. Based on this, the protection status of pipeline is analyzed. If the prototype performance deteriorates, appropriate measures should be taken.
2, in the annual inspection, the output current of the sacrifice anode can be measured and the disconnected cable can be repaired.
3, if the anode output current is significantly reduced, and the anode has not reached its life, the anode cable short circuit is a common reason. An ammeter can be connected in series in the anode cable to measure the anode output current, or a 0.1Ω resistor can be connected in series in the anode cable to measure the voltage drop on the resistor to calculate the anode current output.
4, the ground resistance of the anode is the anode open potential minus the anode closed potential divided by the anode output current.
Near Distance Potential Measurement along the pipeline
The working condition of the cathodic protection system is usually checked by measuring the point position on the test pile. In this way, even if there is a leak point in the pipe coating, if the leak point is far away from the test pile, it is difficult to detect by the test pile potential measurement. Therefore, the closer the potential measurement is built, the more the measured results reflect the actual cathodic protection of the pipeline. In order to eliminate IR drop, a short-circuit device is installed in the cathodic protection circuit, and all the power supplies connected to the pipeline to be detected should be on and off at the same time, so as to measure the on-off and off-power levels of the bag pipeline.
Routine functional testing items and cycle:
project | Test content | cycle |
Sacrificial anode system | Anode operation and status, anode protection potential, output current, open circuit potential | At least once a year |
Forced current system | Operation and status of power supply equipment, instrument output voltage, current (recorded once a day), anode bed resistance (tested as needed) | Every one to three months, depending on operating conditions (such as lightning, stray current, nearby construction activities, etc.) |
Confluence Point | Converging point potential and current | At least once a month |
Connection to external pipes | Current Flow | At least once a year |
Jumper and grounding system | Electrical continuity | At least once a year |
Safety and protection devices | Setting value and | At least once a year |
Polarization potential | Instantaneous power-off potential | Once a year |
For stable systems, the transient power-off potential may be measured at all test installations every three years. | ||
