Protection device and protection method for through power network fault of double-fed induction generator

Abstract

The invention discloses a power grid fault ride-through device and a method for a doubly fed induction generator. The device comprises a controller and a crowbar circuit, the controller is in controlled connection with a generator-side converter and a grid-side converter of the doubly fed induction generator and the crowbar circuit, a three-phase input end of the crowbar circuit is connected with a connection end of a du/dt inductance and the generator-side converter, the crowbar circuit comprises a switch circuit and a drive circuit which is in driving connection with the switch circuit, the controller is in controlled connection with the drive circuit, the switch circuit comprises a bridge circuit comprising full-controlled power electronic devices as constituent elements, and a three-phase input end of the switch circuit is connected to the three-phase input end of the crowbar circuit; and with the device, the method comprises the following steps of closing the generator-side converter and triggering the conduction of the switch circuit in case that a power grid dips to the condition that rotor current is equal to or larger than a conduction threshold value, and switching off the switch circuit in case that rotor current is equal to or smaller than a switch-off threshold value. The invention prolongs the service life of the crowbar circuit and improves the working reliability of the crowbar circuit, and has simple structure and easy implementation.