It is to fast for parallel capacitor power devices, electrical power regulator main power By reverse parallel thyristor module, road circuit is triggered by the other electronic components, and synchronous circuit Control circuit, control circuit of this controller and the control signal of the controller adopts photoelectric isolation, to Avoid interference, when the controller signal for thyristor turn-on, or as to investment Or removal of capacitor, corresponding applicable to 0.4 KV low-voltage capacitor the rapid investment and quick removal.