Harmonic emission before and after changing to LED lamps — Field measurements for an urban area

The paper presents measurements performed in an urban area in the north of Sweden with two individual houses and on LV side of the distribution transformer supplying these two and ten more houses. Measurements of harmonic and interharmonic groups were performed before and after replacing all existing (mainly incandescent) lamps in all 12 houses with LED lamps. The total power of all lamps was reduced from approximately 2300 W to approximately 450 W, per house. All new lamps were low-power-factor lamps. The paper shows the variations of the most important harmonics with time and relevant spectra before and after the replacement. The emission during the evening hours is studied in specific detail. Despite the low power factor of the individual lamps, no change in emission due to the lamps has been observed, neither for any of the two individual houses nor the distribution transformer supplying all 12 houses.