For the <cathodic protection> system, on-site measurement and evaluation of its effectiveness is very important. The relevant technical personnel should master the correct test procedures, understand the functions and use methods of field equipment and instruments, be familiar with the theoretical methods based on the test, and be familiar with the problems with the test results Reasons and solutions.

Determining a cathodic protection corrosion protection effect includes the following:

◆ Structure to reference potential

◆ Test piece potential

◆ Surface potential

◆ Soil resistivity

◆Stray current

Structure vs. electrolyte potential:

Structure-to-electrolyte potential, including pipeline-to-ground potential, tank-to-ground potential, and pipeline-to-electrolyte potential, refers to the potential difference between the metal surface of the structure and the electrolyte when the electrode in contact with the electrolyte is used as a reference for measurement.

The electrolytic potential of the structure is a value measured by a voltmeter connected in parallel in the circuit. The external circuit resistance of this value is relatively high, so a high input resistance voltmeter is required to avoid voltage shunting due to the structure, which may cause deviations in the results.

Potential measurement is a common method used to determine whether sufficient <cathodic protection> is achieved. As the current in the environment acts on the protected object, the potential will undergo a polarization change relative to the environment, and the potential change is a manifestation of polarization. , The measurement can determine whether the relevant <cathodic protection> standards are met, and the voltage drop across the structure and the electrolyte interface must be considered to be excluded, so that fixed potential measurements can be used to evaluate the effectiveness of the cathodic protection system.