Study On Fluorescent Lamp Flicker Under Voltage Containing Interharmonic

In recent years, along with the application of the power electronic technology and the increase of the nonlinear loads, interharmonic pollution becomes more and more serious in power system. Interharmonic is a kind of harmonics whose frequency is not the integer multiple of the fundamental frequency. The main harm of interharmonic is making light flicker, which makes it an electric power quality problem that concerns scholars all over the world. Interharmonic makes fluorescent lamp flicker as well as incandescent lamp which was confirmed by fact and lots of experiment. And the high frequency interharmonic can also makes fluorescent lamp flicker. At present, there is no recognized interharmonic limit standard based on voltage flicker. The study on fluorescent lamp flicker under interharmonic is meaningful and valuable to the deep research on the limit data and limit method of interharmonic, and to the established of the interharmonic limit and tolerate standard.The V-I characteristic of fluorescent lamp with magnetic ballast is established based on the research on its operating and electric characteristics. The equation of the lamp circuit is established. Using the Matlab software, the power response of fluorescent lamp supplied by voltage containing interharmonic with the extreme initial phase is obtained by numerical method. The relations between fluctuation magnitude and frequency of envelope waveforms of instantaneous power and supply voltage are established.The relations of luminous flux fluctuation and power fluctuation of fluorescent lamp with magnetic ballast is established through the analyses of their waveforms and the existent work. The critical luminous flux fluctuation curve at S(t)=1 is obtained based on the study on the operating characteristic of incandescent lamp and the IEC recommending experimental data. By applying the critical luminous flux fluctuation curve to fluorescent lamp, the interharmonic flicker limit curve based on fluorescent lamp is obtained.Through the analyses on the lamp-eye-brain block of the IEC flickermeter model, a simplified flickermeter model based on fluorescent lamp is established, whose input is the power fluctuation waveform of the fluorescent lamp that can be obtained using the numerical method. Using the simulation tool Simulink in the software of Matlab, the simulation model of simplified flickermeter based on fluorescent lamp is established. The simulation result is identical with the experimental curve, which indicates that the method can predict fluorescent lamp flicker cased by interharmonic.