Title :
Excessive neutral currents in three-phase fluorescent lighting circuits
Author_Institution :
Dept. of Electr. Eng., Nat. Univ. of Singapore, Singapore
Abstract :
Causes for excessive neutral currents amounting to 75% and 157% of phase current values in two installations supplying predominantly fluorescent lighting circuits have been identified. These high neutral currents are accounted for by three main components, namely fundamental phase current unbalance, third-harmonic currents caused by saturation of ballasts, and more third-harmonic current caused by third-harmonic voltage waveform distortion in the supply. Solutions are presented to overcome the problem, including a scheme that cancels third-harmonic currents along a common neutral conductor by means of a six-phase system supplied by two transformers connected in antiphase
Keywords :
fluorescent lamps; harmonics; lighting; ballasts saturation; excessive neutral currents; fundamental phase current unbalance; phase current; six-phase system; third-harmonic currents; third-harmonic voltage waveform distortion; three-phase fluorescent lighting circuits; Circuits; Conductors; Current measurement; Floors; Fluorescence; Fluorescent lamps; Phase measurement; Power measurement; Reactive power; Transformers;
Journal_Title :
Industry Applications, IEEE Transactions on
