In view of serious harmonic pollution issue of intermediate frequency smelting furnace at present metal smelting factory

the harmonic load characteristic of metal smelting factory is obtained by the actual measurement

and acomprehensive treatment plan of single tuned passive filter at low voltage side and series filter inductance at high voltage side is proposed further.Only one branch is set in the auto-switching single tuned passive filter at low voltage side.This comprehensive treatment plan has been applied at one 35 kV metal smelting factory.It is shown by the result that the harmonic suppression result of the plan is very good and the network voltage harmonics fully complies with requirement of GB/T 14549—1993 Power quality—Harmonics in public supply network

the harmonic current also has been reduced significantly.And the single branch can meet the requirement of dynamic reactive power compensation of intermediate frequency furnace.