PV systems that are built according to today's installation standards and with high-quality components are generally very safe. Nevertheless, in rare cases, faulty contact points in the PV array or the installation on the DC circuit can cause electric arcs/ sparks.

How are Arc-Faults Formed?

In a series arc-fault a conductor is interrupted, creating a gap in the conductive path while current is flowing. This creates a spark that ionizes the surrounding air, producing plasma. If the current is sufficiently high,enough plasma is created to keep the current flowing across the gap in the conductive path. The current is now conducted via the plasma and is visible as an electric arc.

Unbroken conductor

  • The flow of current is uninhibited

Damaged conductor (increased resistance)

  • The current density is increased.

  • The temperature of the conductor rises.

  • The conductor melts.

Interrupted conductor (failure in continuity)

  • The conductor is destroyed by heat.

  • Plasma is created due to ionization.

  • The current flows in the form of an electric arc.

SMA ArcFix

Effectively Stopping Arcs

To give customers the highest level of safety, we have developed SMA ArcFix AFCI solution. The new technology fully integrates the arc-fault detection and interruption functionality within the inverter. When an arc-fault is detected, the inverter immediately stops operation, interrupting the flow of current across the arc. The inverter displays an error message indicating that an arc-fault has been detected and transmits an error message through its remote monitoring communications interfaces. A manual restart process is required to resume system operations. The system automatically restarts if a false alarm occurs.

Benefits of the revolutionary SMA ArcFix:

  • Reduction in cost and time as the installation of additional arc fault protection devices will no longer be required

  • Full system compatibility

In the future SMA will be fitting all string inverters worldwide with the SMA ArcFix AFCI solution.

Currently the Sunny Tripower Core-1 (STP 50-41) has been equipped with ArcFix AFCI solution.

Technical Information (STP 50-41)