Application of Active Power Filter for Harmonic Prevention in Intermediate Frequency Induction Electric Furnace

The intermediate frequency induction electric furnace used for steel-making usually produces a lot of harmonics.Because the furnace is connected to power grid through transformers directly,harmonic working current increases the transformer energy loss.This work analyzes the working current of intermediate frequency induction electric furnace and the extra energy loss of transformers caused by the current which contains lots of harmonics.Compensating solution is proposed,and the structure of active power filter is described.The simulation and the real test show good effect for the harmonic prevention.In the mean time,the distortion loss of transformer is decreased obviously.For the transformer,the harmonic compensation can reduce harmonic current,decline loss,and extend equipment life.For the company,lots of cost can be saved by adopting compensation technology.