An Equivalent Modeling Method for Direct Drive Wind Farm Considering Unloading Circuit

Abstract

The invention discloses an equivalent modeling method for a direct-drive wind farm of considering an off-load circuit. The equivalent modeling method is characterized by being carried out according to the following steps: (1) building a detailed model of the direct-drive wind farm; (2) generating input wind energy of various units at random; (3) collecting terminal voltage drop values of the units; (4) setting an active current reference value of a grid-side converter; (5) finishing a cluster division according to the conduction condition of the off-load circuit; (6) representing the units with equivalent values; and (7) building an equivalent model of the direct-drive wind farm. According to the equivalent modeling method, accurate representation of the conduction condition of the off-load circuit of each internal unit of the direct-drive wind farm is achieved; and the fitting precision of an equivalent model of the direct-drive wind farm on power external characteristics of the wind farm is improved.

Description

technical field [0001] The invention relates to the field of stability research of a wind power grid-connected system, in particular to an equivalent modeling method of a direct-drive wind farm considering an unloading circuit. Background technique [0002] The direct-drive permanent magnet wind turbine has the characteristics of power decoupling control, no need to install a gearbox, and no direct coupling between the generator and the grid, and has increasingly become the mainstream model in new wind farms. With the grid-connected operation of large-scale wind farms, the impact of wind power on the power system is becoming more and more significant. Grid operators require wind turbines to maintain non-off-grid operation within a certain range of grid faults or voltage disturbances, that is, to have low-voltage ride-through capabilities. In order to improve low-voltage ride-through capability, direct-drive permanent magnet wind turbines are usually connected in parallel wi...

AI Technical Summary

Problems solved by technology

However, most of the existing research results are aimed at squirrel-cage wind farms and double-fed wind farms, and there is a lack of research on equivalent modeling methods for direct-drive wind farms

Scholars generally believe that the generator of the direct-drive permanent magnet wind turbine is not directly connected to the grid, and the isolation effect of the full power converter on the grid-side fault weakens the transient response process of the generator, so the equivalent value of the direct-drive wind farm The generator and machine-side converter modules of the unit are simplified or even ignored in the modeling, and the influence of the conduction of the unloading circuit on the difference in the transient characteristics of the direct-drive permanent magnet wind turbine is not considered

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