Study On Harmonics Analysis And Compensation Scheme Of The 800 Steer Bar Finish Rolling Mill Driving System Of Chongqing Steer Group

There are many silicon controlled rectifiers in The 800 steer bar finish rolling mill driving system (FRMDS) of Chongqing Steer Group for the use of the thyristor rectifier, which brings large harmonics into the power system and has a hurtful inference on the power system and the quality of steel products. So it is significative to compensate the harmonics of FRMDS, which can improve the quality of steel products and the system stability.In order to design the harmonics compensation scheme of FRMDS, harmonics analysis, simulation research and harmonics measurement on the rolling mill are given and their data are compared in this paper. The result shows that the harmonics component is high and mutative because of the variable load in this driving system.Passive filters (PF), active power filters (APF) and hybrid active power filters (HAPF) are effective equipments of harmonics compensation now. The harmonics problem is not solved entirely by passive filters due to their inability to compensate random frequency variations in the current, tuning problems, and parallel resonance with both the load and the grid. APF is better than passive filters because they don't have those disadvantages. So it is viable to use APF to eliminate the harmonics in allusion to the harmonics character of the rolling mill driving system, but it is not economical to use APF only. The best way to compensate the harmonics is using HAPF, which is composed by PF and APF and is possessed of both advantages. Therefore, this paper adopts HAPF to eliminate the harmonics, which PF compensates the main frequency harmonics current and APF compensates others.In the end, this paper designs the HAPF through the front analysis and does simulation research on the driving system joined the part of HAPF. The simulation result shows that HAPF suppresses the harmomc effectively to make the source current waveform close to sine wave and confirms the feasibility of this harmonic compensation scheme.Preparation for harmonic compensation of FRMDS next way is made by this paper.