This is a research on the voltage flicker resulted fromelectric arc furnace in the Tongishia primary substation area.The purposes are to (a) analyze the operation characteristicsof electric arc furnace for the cause of voltage flicker (b)investigate the propagation of voltage flicker among differentvoltage feeders in that area, (c) discuss the posibble reasonsof voltage flicker propagation attenuation, and (d) proposesome feasible methods to reduce the voltage flicker level inthat area. The statistic results of the measurement data atelectric arc furnace transformers show that repeatedlytransient overloads is the major reasons of severe voltageflicker in that area. Itdeduced that the electric arc furnaceplants do not operate the furnace according to the primaryreview conditions. According to the statistics of measurementdata, the voltage flickerperties from the 69kV equivent sourcethrough 69kV transmission lines to 110V customers. The voltageflicker level at the 11.4kV side of secondary substationsattenuates to 80% of it original value, and that at 110Vcustomers sides attenuates to 75% of it oginal value. From thesimulations by EMTP, while nonlinear loads will causeattenuation of voltage flicker, linear loads and networks willnot cause attenuation.
