Fraunhofer ISE Develops Innovative Modular Test Stand for Photovoltaic Inverters with Integrated Arc Fault Detection

Triggering an arc in the TestLab Power Electronics on the test stand for arc detector tests. © Fraunhofer ISE

Fraunhofer Institute for Solar Energy Systems ISE has developed a groundbreaking modular test stand for photovoltaic (PV) inverters, incorporating integrated arc fault detection. This innovative system significantly enhances the safety of solar installations by automatically shutting down in the event of arcing, which can lead to fires. To facilitate more reliable and realistic tests on detectors, a new international standard, IEC 63027, was recently published, with Fraunhofer ISE playing a role in its development.


Arcing in PV systems can occur due to contact issues, such as faulty solder joints in modules or DC wiring problems in inverters. Arc fault detectors (AFD) installed in inverters detect arcs by sensing current jumps or characteristic broadband noise, allowing them to trigger a shutdown before a critical energy threshold is reached. While AFDs have been mandatory for newly installed PV systems in the United States since 2011, they have been offered on a voluntary basis in the European market. However, some building insurers have begun requiring these detectors for fire protection purposes.

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The new IEC standard, developed by Fraunhofer ISE in collaboration with industry representatives, testing companies, and researchers, addresses the weaknesses of the previous US standard. By simulating real operation more accurately, the new standard minimizes undetected arcs and false alarms. It employs a test setup that realistically reproduces electric arcs, using an electronic DC source as a PV simulator and a ball-and-socket joint made of tungsten electrodes to ignite a controlled arc. The test bench’s modular design enables various test scenarios for different types of string inverters, PV module inverters, and string collectors, accommodating DC voltages up to 1,500 V.


The TestLab Power Electronics at Fraunhofer ISE offers accredited tests according to grid codes, efficiency measurements, and impedance spectroscopy investigations of inverters. The introduction of the new test bench expands the institute’s service offerings, further advancing the development and safety standards of PV systems. With Fraunhofer ISE’s expertise and collaboration, the integration of arc fault detection in PV inverters has taken a significant leap forward, ensuring enhanced safety in solar installations worldwide.


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