Reduced safety in low-voltage installations due to fail-to-trip of residual circuit breakers

Inverters, part of solar-power installations, create frequency components beyond 50 Hz. Two of these components, direct current and supraharmonics (2 kHz to 150 kHz), can lead to unwanted tripping and fail-to-trip of residual current breakers.

Inverters, part of solar-power installations, create frequency components beyond 50 Hz. Two of these components, direct current and supraharmonics (2 kHz to 150 kHz), can lead to unwanted tripping and fail-to-trip of residual current breakers. Especially fail-to-trip of the residual circuit breaker jeopardizes personal safety in low-voltage installations. This applies to industrial installations with solar panels but also to residential areas where solar panels are present. A team of eight people will contribute their specific knowledge to gather and create knowledge and be able to assess how serious the problem is. Results from the project can be used for new regulations and recommendations. Measurements and simulations of solar-power inverters will be performed to map the emission and distribution of both direct current and supraharmonics. Residual current breakers of various types will be exposed to direct current and supraharmonics to assess their impact.

Funding: Swedish Energy Agency, Energiforsk.

Project participants: Sarah Rönnberg, Jil Sutaria, Angéla Éspin Delgado, Naser Nakhodchi, Math Bollen, Mikael Byström.