Doubly-fed wind power farm equivalent modeling method for crowbar protection

Abstract

The invention discloses a doubly-fed wind power farm equivalent modeling method for crowbar protection. The method is characterized in that a voltage drop criterion capable of representing the crowbar protection action condition of a doubly-fed wind generation set is provided according to the relationship between rotor current increase and set terminal voltage drop amplitude after the doubly-fed wind generation set has three-phase short-circuit faults, the action criterion is modified according to the difference between a single machine infinite bus grid-connected structure and a topological structure of a wind power farm, the crowbar protection action condition of the set is judged according to the action criterion, and further a wind power farm equivalent model is built by taking the crowbar protection action condition as a cluster classification principle. The crowbar protection action condition of the doubly-fed wind power farm internal set is accurately represented, and wind power farm power external characteristic fitting precision of the wind power farm equivalent model is improved.

Description

technical field [0001] The invention relates to an equivalent modeling method for the off-grid characteristics of a doubly-fed wind farm. Background technique [0002] Doubly-fed wind turbines have the characteristics of maximum power tracking, power decoupling control, and small converter capacity, and are the mainstream models in current wind farms. In order to improve the low-voltage ride-through capability of doubly-fed wind turbines, a crowbar is usually installed on the rotor side to protect the power converter from the impact of short-circuit current. The input of the crowbar protection circuit not only makes the unit lose control of the output power, which may induce the chain disconnection of the unit in the wind farm, but also increases the weak feed of the wind farm due to the connection of the crowbar resistance. Therefore, the action of the crowbar protection has an important influence on the operating characteristics of the wind farm. [0003] When carrying o...

AI Technical Summary

Problems solved by technology

However, the current research results do not take into account the impact of crowbar protection on the equivalent modeling of units and wind farms

The research shows that if the crowbar protection is considered, the traditional grouping criterion index is difficult to accurately represent the crowbar protection action of the unit, resulting in a large error in the equivalent model of the wind farm

Some scholars have studied the relationship between the depth of voltage drop at the terminal of double-fed wind turbines and the protection of crowbars, but they have not considered the influence of the topological structure of the wind farm on the critical value of voltage drop at the terminal of the wind farm.

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