A wind turbine generator, comprising: at least two power transmission systems connected in parallel with each other; a control system, wherein the control system comprises an upper controller and control subsystems provided correspondingly to the power transmission systems, and each of the control subsystems comprise bottom controllers; wherein each of the power transmission systems comprises a power generation subsystem and a power transmission subsystem, functional units of the power generation subsystem comprise generator windings (11a, 12a) and generator winding radiators (11b, 12b), functional units of the power transmission subsystem comprise machine side switches (11c, 12c), converters (11d, 12d), radiators of converters (11e, 12e), network side switches (31a, 32a) and transformer windings (31b, 32b); the bottom controllers are configured for monitoring operating state parameters of each functional unit in corresponding power transmission systems, and under the condition that it is determined that corresponding functional units meet abnormal conditions according to the operating state parameters, sending the operating state parameters of the corresponding functional units to the upper controller; the upper controller is configured for generating operation instructions under the condition that it is determined that faults of the corresponding functional units occur according to the operating state parameters of the corresponding functional units and controlling the power transmission systems to work according to the operation instructions, and in a case where one of the functional units fails, only the power transmission system where the functional unit is located is affected, and the normal operation of other power transmission system is not affected. at least two power transmission systems connected in parallel with each other; a control system, wherein the control system comprises an upper controller and control subsystems provided correspondingly to the power transmission systems, and each of the control subsystems comprise bottom controllers; wherein each of the power transmission systems comprises a power generation subsystem and a power transmission subsystem, functional units of the power generation subsystem comprise generator windings (11a, 12a) and generator winding radiators (11b, 12b), functional units of the power transmission subsystem comprise machine side switches (11c, 12c), converters (11d, 12d), radiators of converters (11e, 12e), network side switches (31a, 32a) and transformer windings (31b, 32b); the bottom controllers are configured for monitoring operating state parameters of each functional unit in corresponding power transmission systems, and under the condition that it is determined that corresponding functional units meet abnormal conditions according to the operating state parameters, sending the operating state parameters of the corresponding functional units to the upper controller; the upper controller is configured for generating operation instructions under the condition that it is determined that faults of the corresponding functional units occur according to the operating state parameters of the corresponding functional units and controlling the power transmission systems to work according to the operation instructions, and in a case where one of the functional units fails, only the power transmission system where the functional unit is located is affected, and the normal operation of other power transmission system is not affected.