15 Compensation of Reactive Power - Case Study

Fluorescent lamps are the only common device where putting the most efficient way of compensation, at the point of origin within the luminaire, is common practice. Other compensation units are installed more centrally. In that case, if the compensator for fundamental reactive power were combined with a harmonics filter this would solve several problems at the same time with the same device. The risk of attracting pollution from the supply while sweeping one’s own is not as high as generally assumed, at least not when the premises are supplied by their own distribution transformer. The voltage drop in a transformer, described in terms of its short-circuit voltage, is largely inductive. Therefore, a transformer with a short-circuit voltage rating of 4% has a relative reactance of nearly 12% at 150Hz and close to 20% at 250Hz. If the neighboring premises also use their own transformers, the impedance between the two doubles again. However, the impedance of a transformer to harmonics varies a great deal depending upon: