Calculation method for equivalent virtual inertia time constant of double-fed wind driven generator

Abstract

The invention discloses a calculation method for an equivalent virtual inertia time constant of a double-fed wind driven generator. According to the calculation method, a virtual inertia control technique is introduced, the virtual inertia time constant of the double-fed wind driven generator is defined, and the value of the virtual inertia time constant is calculated quantitatively; to be more specific, electromagnetic torque increments in speed control and inertia control steps related to an inertia response process are calculated and are substituted into a rotor electromechanical transient equation represented by deviation values to acquire the ratio of an system synchronization angular frequency increment to a wind driven generator rotor angular frequency increment; the ratio is substituted into a definition expression to acquire a frequency domain expression of the virtual inertia time constant, a time domain value is acquired through Laplace inverse transform, and accuracy of the expression is verified through comparison between a calculation result and a simulation result. The calculation method has the advantages that the equivalent virtual inertia time constant of the double-fed wind driven generator is different from a fixed inertia time constant of a wind generating set, the value of the equivalent virtual inertia time constant changes along with time during inertial response, and accuracy of the calculation result is high; the calculation method is the important foundation of further research on electric system dynamic frequency characteristics with wind power inertial responses.

Description

technical field [0001] The invention belongs to the technical field of new energy power system operation and control, and in particular relates to a method for calculating the equivalent virtual inertia time constant of a doubly-fed fan. Background technique [0002] In the initial stage of power shortage in the power system, the dynamic active power balance is mainly achieved by the inertial response of the synchronous generator and the asynchronous motor. For double-fed wind turbines with increasing penetration rate, due to the existence of converter power electronic interface, the rotor speed is decoupled from the system frequency, and double-fed wind turbines cannot provide inertial response and dynamic active support. Large-scale double-fed wind turbines are connected to the grid. It will inevitably lead to the deterioration of the dynamic frequency characteristics of the power system under the condition of power shortage. Simulation of inertial response of DFIG is an ...

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Problems solved by technology

At present, there is no research on this problem in any literature and results. The invention lays the foundation for key issues such as power system dynamic frequency safety and stability assessment, low-frequency load shedding strategy formulation, etc. by calculating the equivalent virtual inertia time constant of double-fed wind turbines.

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