TSF (Thyristor Switched Filters) main circuit and characteristics is analyzed. Then expert systems are applied to the control system in order to avoid operation surge. According to the results of simulations experiments and actual run, the transition procession current’s peak value are cut down greatly with new control system. With the TSF was used, the current total harmonic distortion is obviously reduced, and the power factor met the national requirements. The results of simulations and experiments show ...