TSF, a low-voltage dynamic reactive power compensation device, is controlled by an intelligent controller to dynamically switch the thyristor filter, which integrates harmonic filtering, reactive power compensation and power quality detection. It can filter the harmonic of the power grid to meet the national standard requirements, compensate the reactive power loss in the power grid in real time, improve the power factor and reduce the line loss, thus improving the load capacity and power supply quality of the power grid. At the same time, TSF can also monitor the three-phase voltage, current, frequency, active power, reactive power, power factor, harmonics and other operating data of the power grid in real time, which is suitable for occasions with large load harmonic content, low power factor and large load fluctuation. TSF device has perfect protection measures such as overvoltage, undervoltage, open phase, overcurrent, short circuit, transient overvoltage, acousto-optic alarm, etc., and there is no problem of reactive power reverse transmission and harmonic amplification.