Harmonic analysis and mitigation in distribution grids with high penetration of power inverters

Inverters of large heat pumps in an urban low voltage grid generate current harmonics and cause consequently significant variations of the respective voltage harmonics. The voltage level at each grid point is not only influenced by the operation of such inverters, but higher harmonic voltage amplitudes can be expected, caused by the sum of all loads in the grid. The paper provides a comprehensive harmonic analysis of a typical urban distribution grid including heat pumps and presents insights on the variations and impact on the voltage profile of the 15th harmonic currents. An active harmonic filter was installed to enhance the power quality, by compensating the harmonic currents and by improving the voltage profile at grid points close-by the heat pumps.