Comparison of laboratory and grid measurements of 9 kHz to 150 kHz appliance emissions

The frequency range from 9 kHz to 150 kHz is still lacking a complete normative measurement framework. At the moment, it is not fully clear how well measurements of equipment emissions performed in laboratory environment compare with emissions measured in real low voltage networks, mainly due to different impedance conditions. This paper addresses this issue by presenting a comparison of emissions from a selected set of appliances measured in the laboratory with on-site low voltage network measurements of the same appliances. Several laboratories participated in this comparison, and different low voltage network locations have been taken into consideration. The comparison demonstrates overall agreement between the results obtained in different locations and conditions, especially where high-amplitude narrowband emissions are concerned. However, some differences have also been identified in the analysis between laboratory and grid measurements as well as between different laboratories. This might be due to the use of different (compliant) instruments with different characteristics or due to the use of artificial mains networks, which might not be fully representative of grid impedance.