What is AFCI protection on inverters?

Arc Fault Circuit Interrupter (AFCI) protection in inverters is an advanced technology used in photovoltaic systems to prevent electrical arcs on the direct current (DC) side. Electrical arcs can lead to fires, so detecting them and immediately shutting down the circuit is crucial for safety.

Arc detection methods are based on the analysis of current or voltage frequency measurements. The analysis also includes characteristic information such as frequency point, energy and variation from which the occurrence of an electric arc is inferred.

Operation of AFCI Security

  • Detection of electric arcs: AFCI continuously monitors the electrical circuit for characteristic signals indicating arcing. Electrical arcs can occur due to damaged insulation, loose connections, corrosion or other installation defects. In photovoltaics, the most common place for arcing to occur is at the connections of DC connectors - for example, because the connector was not properly welded by the installer.
  • Response to Arc Detection: When the AFCI detects a potential arc, it immediately breaks the circuit, preventing further arc spread and a potential fire hazard.
  • Analysis and diagnostics: Some AFCI systems can also record and analyse data on detected events, allowing further diagnosis and prevention of future problems.

Electric arc in photovoltaic systems can arise from several causes, often related to improper installation, damage or wear of system components. Here are the main factors leading to arcing in photovoltaic installations:

  1. Damage to cables and connections: Broken, abraded or damaged cables can lead to arcing. Also, loose electrical connections, both in photovoltaic panels and in other system components such as DC connectors, can cause arcing.
  2. Damage to Photovoltaic Panels: Cracks or mechanical damage to photovoltaic panels can lead to arcing.
  3. Incorrect installation: Installation errors, such as inadequate earthing, incorrect cable sizes or poor connections, can increase the risk of arcing.
  4. Aging and Corrosion of Components: Over time, photovoltaic system components can degrade, increasing the risk of arcing, such as corrosion of DC connectors.
  5. Excessive current or voltage: In some cases, especially as a result of system failures or malfunctions, surges can occur, which in turn can lead to arcing.
  6. Weather and environmental conditions: For example, very high humidity, rain or hail can increase the risk of arcing, especially if the installation has existing weaknesses.
  7. Animals: Nesting birds, rodents or other animals can damage cables and other components, which can also lead to arcing.

In summary, AFCI protection in inverters is a key element in ensuring the safety of photovoltaic installations, protecting against the risk of fire resulting from electrical arcs.

Examples of inverters with integrated arc detection (AFCI):

 

Find out more! 

 AFCI-whitepaper fire-and-solar-pv-systems-flyer-pl

AFCI-whitepaper

Read also: