Optimization method of low-frequency oscillation control parameters for doubly-fed wind turbine grid-connected system with virtual inertia

Abstract

The invention discloses a low-frequency oscillation control parameter optimization method of a grid-connected double-fed fan with virtual inertia belonging to the technical field of power system stability analysis. The method is realized by a processing system comprising a sequentially connected information acquisition module, a robust random optimization parameter adjustment calculation module and a parameter adjustment result output module, comprising three steps of information acquisition, parameter adjustment calculation and output parameter adjustment result optimization, and obtaining aset of control parameter policy variables; Judging whether the doubly-fed fan is the cause of inducing low frequency oscillation can guide the optimization of control parameters. After the parameter optimization strategy is applied, the power angle response level of the fan is effectively improved, the fan no longer transmits oscillation energy to the power network, and the low-frequency oscillation of the fan-connected system is restrained.

Description

technical field [0001] The invention belongs to the technical field of power system stability analysis, and in particular relates to a power system, in particular to a low-frequency oscillation control parameter optimization method of a double-fed fan grid-connected system with virtual inertia. Background technique [0002] Traditional double-fed wind turbines do not have the ability to adjust inertia. By introducing virtual inertia control, wind turbines can release a certain amount of rotational kinetic energy to the grid when the system frequency changes, or absorb a certain amount of electrical energy from the grid and convert it into rotational kinetic energy, thereby improving its grid-connected performance. Although the introduction of virtual inertia can improve the inertia and frequency characteristics of the disturbed system to a certain extent, however, the dynamic characteristics of the virtual inertia and the interaction with the phase-locked loop will affect the...

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Problems solved by technology

Additional damping control is a linear control strategy. Its basic idea is to add processed local information or wide-area information to the wind turbine rotor side converter to adjust its control strategy. It has the advantages of simple structure and easy application. However, The basic idea of ​​this method is still based on a deterministic model. Facing a time-varying system with uncertain parameters, when the operating conditions change, its control effect is difficult to meet the requirements.

Adding a compensation device is a nonlinear control strategy, which can enhance the additional damping of the wind turbine, make up for the deficiency of the linear control strategy, and solve the problems caused by the complex model and too many unknown factors of the wind power grid-connected system containing double-fed wind turbines. However, this method ignores the influence of the virtual inertia of the fan on the damping characteristics of the synchronous machines, and does not fully consider the ability of the control link of the fan itself to participate in the smoothing of the system oscillation

The method of optimizing control parameters starts from the fan itself, without additional devices, and has the advantages of cost saving and easy implementation. However, the existing methods have not yet considered how to ensure the stability of the system power angle under the condition of providing frequency support, and the use of internal fan There is still a lack of research on key control parameters to stabilize oscillations

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