Harmonic impacts of widespread use of CFL lamps on distribution systems

The widespread usage of more efficient but potentially harmonic rich residential loads such as CFL (Compact Fluorescent Light) lamps can be expected to contribute to increased harmonic levels in distribution systems. In some cases, additional distortion can push already high harmonic levels above the recommended limits. Also, the impact can be further exacerbated by the presence of reactive compensation in the form of capacitor banks on the feeders. This paper attempts to quantify the increase in voltage distortion at a distribution substation for the worst case scenario of CFL lamps replacing all the incandescent lamps. Detailed distribution system models have been developed for the purpose of computer simulations and the harmonic injection has been represented using harmonic spectrums obtained through laboratory tests carried out on actual off-the-shelf CFL lamps. One potential solution to mitigate anticipated harmonic levels has been studied and presented. The final goal of this effort is to develop guidelines that utility can follow in designing or modifying their distribution systems to handle increased harmonic injections that are expected in future.