The invention discloses a method used for letting a large-scale wind generating set to ride through when a power network has
low voltage failure, and the method belongs to the technical field of the
electric power transmission. Aimed at solving the connecting problem of the
wind power generation, the method has the technical proposal that a three-phase passive
impedance network or a resistance network is connected between the wind generating set and the power network in series, and a three-phase AC switch composed of a
power semiconductor device is connected with the passive
impedance network or the resistance network in parallel; when the power network has the
low voltage failure, the three-phase AC switch is switched off, thereby accessing into the passive
impedance network or the resistance network; and when the
voltage is recovered, the three-phase AC switch is switched on, thereby enabling the passive impedance network or the resistance network to have
short circuit, and recovering the normal connection between the wind generating set and the power network. The invention not only can ensure the security of a doubly fed induction wind generating set when the power network has the
low voltage failure, but also can uninterruptedly provide currents for the power network, thereby enabling a line protecting device to reliably work.