A few weeks ago we talked about the possible reasons why fires occur in photovoltaic installations, and one of the strong points was the discussion about electric arcs. This time, we are going to delve into one of the most important reasons for these fires and see how we can prevent them from happening.
What is an electric arc?
An electric arc is an electrical discharge that occurs between two points with a significant electrical potential difference.. This can happen when a break in the insulation occurs between two electrical conductors, such as wires or terminals, allowing electrical current to flow through air or a gaseous medium.
The electric arc produces an intense emission of light and heat, and can be dangerous due to the high temperature and the possibility of burns, fires or explosions. It can be found in a variety of environments, from electrical power distribution systems to welding equipment and industrial electrical circuits.
What can cause electric arcs?
As we discussed previously, electrical arcs represent a form of short circuit that can cause electrical problems in our facilities or even end in a fire. Additionally, they constitute a significant risk for maintenance personnel working on high voltage lines, and can result in serious burns. It is crucial to properly address the prevention of these electrical arcs to ensure the safety of both our facilities and our human team.
When can an electric arc occur?
In general, photovoltaic installations are low voltage, but despite this they are susceptible to electric arcs. In most cases, electric arcs occur in installations that have not been properly coupled or that
Adverse environmental conditions
The presence of moisture, dust or dirt on the solar panels or electrical components can cause electrical arcs.
Mechanical damage or wear
If the components of the photovoltaic installation are mechanically damaged or worn due to age, electric arcs can occur.
Failures in electrical components
Problems such as loose wires, faulty connections, short circuits, or other failures in inverters, charge controllers, or other devices can cause arcing.
Errors during installation
A poor electrical installation is usually one of the most frequent reasons for arcs to occur, either due to the use of cables that are not suitable, poor crimping of the same or low quality of the materials.
How can we avoid electric arcs in photovoltaic installations?
As we have discussed previously, the quality of the electrical installation is essential for its optimal and safe operation. Installers must avoid any type of poor or "sloppy" work and ensure that all necessary safety measures are taken.. In addition to these aspects, there are elements inherent to the installation itself that incorporate measures against electric arcs.
A notable example are the protections against electric arcs integrated into Auxsol inverters (AFCI Protection). These protections not only cover surges, but are also designed to mitigate direct current (DC) arcs, which significantly expands the protection of the circuit. In fact, these protections are capable of covering distances of up to 300 meters, which reinforces the security of the electrical system in general.
In managing problems like these, DC protections are essential. In the case of thermal protection, the switch trips when the electric current exceeds the nominal value. As more heat is generated, the bimetallic contact heats up and expands. Thermal protection can help in cases where the current is increasing. In this way, it will be much easier for us to avoid situations that lead to a fire.
