Suppression method for subsynchronous resonance of asynchronous wind power generator system by UPFC (Unified Power Flow Controller)

Abstract

The invention discloses a suppression method for subsynchronous resonance of an asynchronous wind power generator system by a UPFC (Unified Power Flow Controller). The suppression method is used for monitoring a current passing through the UPFC, the current is adjusted by a feedback stage to control corresponding reactive power, a voltage of a machine end is adjusted to a normal level, so that a certain damping torque is generated in a power generator, and the subsynchronous resonance is suppressed; and meanwhile, at a series connection side of the UPFC, the reactive power of a circuit is changed by changing a voltage of the series connection side, a reactive current in the asynchronous wind power generator system is affected by change of the reactive power of the circuit, a mechanical torque is considered to be constant in an electromagnetic transient condition, the rotational speed of a rotor of the asynchronous power generator is increased due to increase of an inductance current, the damping torque under a subsynchronous frequency is generated, and the subsynchronous resonance is suppressed. By the suppression method, the stability of a wind power plant system is improved, meanwhile, subsynchronous damping in the system can also be increased, and the subsynchronous resonance of the wind power generator can also be suppressed.

Description

technical field [0001] The invention belongs to the technical field of power electronics, and in particular relates to a method for suppressing subsynchronous resonance of an asynchronous wind power generator system by UPFC. Background technique [0002] In recent years, wind power generation has developed rapidly all over the world, and large-scale wind farms with a scale of one million have been gradually built. However, large-scale wind farms are generally located in relatively remote places, often far away from the load center, and long-distance power transmission will be inevitable. In order to reduce line losses, increase transmission capacity and improve system stability, series compensation devices are used in long-distance transmission lines. [0003] While the series compensation device effectively increases the power transmission capacity, it may also cause subsynchronous resonance phenomenon. The wind turbine is composed of rigid parts such as blades, hubs, low...

AI Technical Summary

Problems solved by technology

The wind turbine is composed of rigid parts such as blades, hubs, low-speed shafts, high-speed shafts, and gearboxes. When the system is disturbed, the series compensation device in the line may cause subsynchronous resonance of the wind turbine, resulting in the shutdown of the wind farm. transport, or even damage to wind turbines, resulting in system instability

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