Implications for Distribution Networks of High Penetration of Compact Fluorescent Lamps

The desire to reduce electrical loading by using energy efficient lighting has resulted in a high level of interest in replacing conventional incandescent lamps with compact fluorescent lamps (CFL). This has resulted in the New Zealand Government, through the Electricity Commission of New Zealand, running campaigns to install five CFLs in every home by, subsidizing the cost of suitable CFLs. CFLs are however, a nonlinear load hence inject harmonics into the electrical network. The CFL use electronic ballasts and the design of these have an enormous impact on the electrical performance of the CFL. In the past, the harmonics injected into the network by CFLs has been ignored as each is very small as the typically CFL is only 20 Watts. However, if widespread adoption of CFLs occurs, the combined effect of all these small sources can be just as detrimental as one large source, and is even harder to mitigate due to their distributed nature. This paper presents the results of a study to quantify the effect widespread adoption of CFLs will have on a typical distribution network. The two aspects investigated were harmonic distortion and system losses. To enable 28 800 homes to be represented a methodology for modelling a large number of distributed loads using Norton equivalents was developed and applied. In order to assess losses, a fundamental frequency power-flow was also incorporated.