The GRIDCON ACF Building version is a 4 wire device and belongs to the new generation of Active Harmonic Filters. The GRIDCON ACF active filters use a new 3 - level technology. The 3-level circuit is based on twelve IGBTs, whereas conventional 2-level active filters only comprise of six. The special circuitry halves the voltage load of the power semiconductors. On the one hand this results in lower losses and on the other hand enables use in grids with a higher rated voltage. This 4-wire active filter is optimized for filtering single-phase loads, and protects against neutral conductor overloads. Common applications are in 208 V and 400 V networks. Given the isolated main cooling duct and low losses, reliable operation is possible under demanding environmental conditions. The modular concept simplifies subsequent expansion or modification, allowing the filters to grow with their tasks. The operator can perform parameterization for new or changed tasks himself, ensuring long-term flexibility. GRIDCON® ACF Building version is already prepared for future functionality to compensate harmonics even beyond the 51st. GRIDCON® ACF Building version monitors and autonomously reduces malfunctions in plant grids and ensures compliance with voltage-distortion standards.