Cathodic protection is an effective method for safeguarding underground pipelines against soil corrosion and stray current-induced corrosion.
Cathodic polarization of underground steel pipelines is achieved by applying a direct current supplied from a cathodic protection rectifier station (CPRS). The pipeline is connected via a drainage cable to the negative terminal of the CPRS and acts as the cathode. Anode groundbeds are installed either vertically or horizontally, interconnected by drainage cables, and connected to the positive terminal of the CPRS. The effectiveness of cathodic protection is evaluated based on the magnitude of cathodic polarization (i.e., the shift in pipeline potential measured using a reference electrode).
A test station (TS) is installed at the anode groundbed within a protective enclosure.
The number of anode groundbeds is determined by engineering calculations.
Isolating joints and monitoring instruments are installed on pipelines to enhance the efficiency, operational reliability, and controllability of the cathodic protection system.
Schematic of cathodic protection for an underground pipeline
1 – Pipeline. 2 – Anode groundbed. 3 – Drainage cable.
4 – Test station (TS). 5 – Cathodic protection rectifier station (CPRS).
6 – Perforated vent pipe. 7 – Bentonite (clay) backfill.
Cathodic polarization of underground steel pipelines is achieved by applying a direct current supplied from a cathodic protection rectifier station (CPRS). The pipeline is connected via a drainage cable to the negative terminal of the CPRS and acts as the cathode. Anode groundbeds are installed either vertically or horizontally, interconnected by drainage cables, and connected to the positive terminal of the CPRS. The effectiveness of cathodic protection is evaluated based on the magnitude of cathodic polarization (i.e., the shift in pipeline potential measured using a reference electrode).
A test station (TS) is installed at the anode groundbed within a protective enclosure.
The number of anode groundbeds is determined by engineering calculations.
Isolating joints and monitoring instruments are installed on pipelines to enhance the efficiency, operational reliability, and controllability of the cathodic protection system.
Schematic of cathodic protection for an underground pipeline
1 – Pipeline. 2 – Anode groundbed. 3 – Drainage cable.
4 – Test station (TS). 5 – Cathodic protection rectifier station (CPRS).
6 – Perforated vent pipe. 7 – Bentonite (clay) backfill.
