Cathodic Protection

A very effective means of preventing corrosion on system-critical conductive metals, cathodic protection is very generally the practice of protecting a metal from oxidization by inducing a potential between layers of dissimilar metals. Cathodic protection systems may involve inducing a direct current (DC) from a source such as photovoltaic panels or by simply coating with certain so-called “noble” metals, such as the zinc used in the galvanization process.

Cathodic protection theory was first recognized in the early 19th century when an officer of the British tried to reduce the corrosion of copper. Today the simplest form of a cathodic protection system is ubiquitously found on galvanized items. This is often called the sacrificial anode method, because eventually the cathodic protection shielding zinc will flake off as it’s consumed by the oxidization reaction.

More complicated cathodic protection equipment is commonly used for pipelines, boats and other devices made of oxidizing metals and, especially those in difficult conditions such as marine or underground environments. Because a DC voltage of some sort is required, and this amount does very greatly, a cathodic protection system is, in theory, run on DC current alone.

As such, photovoltaic (PV) systems are very useful in these applications, especially since you’ll not require an additional cathodic protection rectifier to convert alternating current (AC) to DC. When using a solar cathodic protection system, the install is also relatively simple. While cathodic protection rectifiers are not usually a large expense, it certainly can be, adding as much as 50% to the cost of a new system. It certainly is an unnecessary expense if using a PV system.

When designing cathodic protection system, make sure your supplies are designed for solar systems. Using the wrong type of controller can result in dramatic losses even in very well designed cathodic corrosion protectors. When performing cathodic protection testing, it is always a good idea to measure your losses in the system and make sure you’re not missing something significant. In poorly designed systems, only 20% of the power coming off the solar panel is actually making it into the CP system.

When choosing a cathodic protection equipment supplier, be sure they understand how to work with solar equipment. PV systems are very different, especially when it comes to testing and gauging the actual efficiencies of the system. Some cathodic protection services specialize in solar applications and can give you a very good idea of what you will require when you describe your project.