A Dynamic Equivalence Method for Doubly-fed Fans Considering Subsynchronous Oscillation Characteristics

Abstract

The invention discloses a double-fed fan dynamic equivalence method considering subsynchronous oscillation characteristics, which comprises the following steps: deriving an external characteristic equivalence model according to voltage flux linkage equations of a stator and a rotor of a double-fed fan, connecting current collection circuits with complex wires, and establishing equations for inputand output by adopting an integral processing method to obtain impedance parameters of the current collection circuits. The method comprises the following steps of: constructing judgment matrixes of all factors based on an analytic hierarchy process by taking consistency of subsynchronous oscillation characteristics of fans before and after equivalence as a constraint condition, introducing cosinesimilarity to calculate similarity of characteristic vectors of the judgment matrixes, and if the similarity is smaller than a threshold value, considering that the subsynchronous oscillation characteristics of the two fans are consistent and can be regarded as a coherent group. And finally, calculating the equivalent transient internal potential of the equivalent machine and the equivalent parameters of each equivalent unit by taking the actual output active power of the double-fed fan as the weight. Therefore, the equivalence simplification requirement of the large power grid comprising thelarge-scale wind turbine generator set is met, the consistency of subsynchronous oscillation before and after equivalence can be ensured, the real dynamic characteristics of the wind power plant canbe better reflected, and a foundation is laid for subsequent analysis of the suboscillation characteristics of the large-scale wind power plant and the influence of grid connection on the large powergrid.

Description

technical field [0001] The invention relates to the technical field of renewable energy, in particular to a dynamic equivalent method of a doubly-fed wind turbine considering the characteristics of subsynchronous oscillation. Background technique [0002] In recent years, with the rapid development of green and renewable energy, wind energy, as one of the most important clean energy sources, has attracted the attention and attention of various countries due to its huge advantages of abundant energy and easy access. Wind power will play an increasingly important role in the future energy arena. Modeling of wind turbines and their impact on power systems has been extensively studied. However, with the explosive growth of wind farms, a wind farm usually consists of hundreds of wind turbines, so it is impossible to carry out detailed modeling and analysis on each wind turbine. At this time, it is necessary to perform equivalent treatment on the wind farm, carry out reasonable ...

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Problems solved by technology

However, overcompensation of the series compensation may lead to subsynchronous oscillation phenomenon

In 2009, in a wind farm in Texas, the interaction between doubly-fed wind turbines and fixed series compensators produced subsynchronous oscillations, and the amplitude continued to increase, causing a large number of wind turbines to go off-grid and damage the equipment.

For the use of AHP to construct the basis for normalized grouping, there is still no patent for applying it to the grouping of DFIGs, and the control characteristics and key parameters of synchronous generators and DFIGs are quite different, so it is necessary to Basis for grouping of doubly-fed wind turbine construction system

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