Self-bias thyristor switch for quickly switching power capacitor

The utility model discloses a self-bias thyristor switch for quickly switching a power capacitor, which comprises a switching judging unit sending a switching command according to a switching signal, a cutting-off processing unit sending a cutting-off command, and a switching device controlled by the switching command and the cutting-off command. At least two power phase lines among the three power phase lines connected with the power capacitor are connected with the switching device in series. Compared with the prior art, the self-bias thyristor switch for quickly switching the power capacitor can effectively avoid the damage and failure of the switching thyristor caused by large-extent voltage fluctuation of power grids, improves the reliability of a controller, avoids the surge currents in the prior art, balances capacitance potential when the power capacitor is switched, protects the thyristor, and prepares for quickly switching the power capacitor next time.