In this method, the current required for cathodic protection is injected into the structure under protection (cathode) by a rectifier transformer and anode bed, and as a result, an electrochemical reaction takes place and the corrosion of the structure under protection is prevented. Unlike the method of sacrificial anodes, in the applied current method An external source is required to provide the required current for protection.
Cathodic protection system is also used as one of the cathodic protection methods. In this method, the electric current is injected directly into the metal so that the cathode of the metal becomes instead of the cathode of the electrolyte and as a result it is protected from corrosion.
This system usually includes the following components:
1. Side current system (Impressed Current System): In this system, electric current is injected into the metal from an external source, such as a battery or a direct current feeding system. This electric current is continuously supplied by a power source and transferred to the metal to protect it from corrosion.
2. Anodes: Anodes are used in the current injection protection system to provide the necessary electric current to the metal. Anodes are usually made of metals such as titanium, magnesium or aluminum and are exposed to the electrolyte as the positive (anode).
3. Electrolyte: Electrolyte is used in current injection protection system as a medium to transfer electric current between anodes and metal. The electrolyte usually consists of salt solutions that surround the metal.
4. Connections: Connections in the current injection protection system are used to connect anodes, metal and power supply to each other and create an electrical circuit between them. Connections usually include wires and metal parts.
These components work together to inject electrical current into the metal and protect it from corrosion. This method is usually used in cases where cathodic protection is not able to provide the necessary electric current by means of auxiliary feeding.
The type of anodes used in this method is important because they should have little decomposition.