How does corrosion occur?
Corrosion is natural phenomenon common to all metals, and sometimes non-metals such as concrete. The process often results in the deterioration of the metal. In many cases, the metal deterioration can be severe enough to warrant replacement or repair. Corrosion is an electrochemical process, very similar to a battery where electrons flow between an anode and a cathode. For corrosion to occur, the following four elements are required:
- Anode: The area of deterioration or site on metal surface from each current flows and corrosion occurs
- Cathode: The area of protection or site on metal surface which receives current flows and no corrosion occurs
- Electrolyte: A medium capable of conducting electric current
- Metallic Path: Connection between the anode and cathode
Why do you need cathodic protection for your solar power infrastructure?
Corrosion can destroy the integrity of your infrastructure. Steel posts/piles are an extremely important part of solar power installation. Solar panels and associated infrastructure are often subject to high wind exposure and other load-bearing forces, such as the operation of a sun-tracking system.
The corrosion of supporting structures beyond an acceptable level will cause loss of structural strength. The continuous corrosion will weaken the structure and may cause the need for total replacement of the infrastructure. Corrosion control solutions can provide a cost-effective corrosion control system designed to protect solar power infrastructure. Cathodic protection (CP) is a technology used to protect buried or immersed metals from corrosion. It is defined as the reduction or elimination of the corrosion process by either making the corroding metal a cathode, via an impressed direct current or by connecting metallic structure to a sacrificial or galvanic anode.
Types of cathodic protection
Impressed current cathodic protection: This type of cathodic protection system requires an external power source (transformer rectifier, solar power unit) and is typically applied to metallic structures with large surface areas such as large population of bare/galvanized steel piles, transmission pipelines, sheet pile seawalls or bottoms of abovegrade storage tanks.
Galvanic cathodic protection: This type of cathodic protection system is selfpowered and is the simplest form of cathodic protection. Typically it is applied to metallic structures in a soils/water environment where there is limited exposed surface area (i.e. well-coated short distance pipelines and other structures with high quality coating). Alternately, it can also be used for large uncoated
structures in sea water application. This will warrant a large size cathodic protection system.
Cathodic protection has been in use for decades to protect underground pipelines, ship hulls, offshore oil and gas production platforms, underground steel storage tanks, interior submerged portions of tanks and many other structures. Structures designed with cathodic protection system are known to meet or exceed the design life whereas non-cathodic structures fail prematurely