Harmonics in multiple light dimmer systems

Static power converters have found a wide range of applications in all kind of industries. Even ships do not escape this technology and, consequently, to the problem of harmonics. The harmonic disturbances are very critical on a ship supply network because it is a local one and its impedance has a finite value. Therefore, the prediction of the harmonics level caused by static power converters may help to evaluate accurately the characteristics of the network devices to be installed, such as generators, powerlines, transformers etc.. The aim of this paper is to study the harmonics generated by a large number of light dimmers. Due to the randomness of the operating conditions of each dimmer, a statistical approach seems the most suitable in order to analyse the global behaviour of the system. A multiple single-phase dimmer installation and the influence of some parameters on the line current harmonics are investigated in a first part. Afterwards, the same study is applied to multiple single-phase dimmers supplied by a three phase network