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For the < cathodic protection > system, it is very important to evaluate the effectiveness of the on-site measurement, and the relevant technical personnel should master the correct test steps, understand the functions and use methods of field equipment instruments, be familiar with the theoretical methods on which the test is based, and be familiar with the causes and solutions of problems in the test results.
To determine the effectiveness of a cathodic protection against corrosion, the following is included:
◆ Structure-to-reference potential
◆ Specimen potential
◆ Surface potential
◆ Soil resistivity
◆ Stray current
Structure to electrolyte potential:
Structure-to-electrolyte potential, including pipeline-to-ground potential, storage tank-to-ground potential, and pipeline-to-electrolyte potential, refers to the potential difference between the metal surface of the structure and the electrolyte measured by the electrode in contact with the electrolyte as a reference.
The electrolyte potential of the structure is measured by a voltmeter connected in parallel in a circuit, and the resistance of the external circuit is high, so it is necessary to use a high-input resistance voltmeter to avoid deviations in the results due to voltage shunting caused by the structure.
Potentiometric 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 change relative to the environment, and the potential change is the manifestation of polarization, and the measurement can be carried out to determine whether the relevant < cathodic protection > standards are met. Consideration must be given to excluding the voltage drop that flows through the structure and electrolyte interface in order to evaluate the effectiveness of a cathodic protection system using fixed potential measurements.
Article source: Suzhou Bogao Cathodic Protection Technology Co., Ltd., website: www.syncor.net
