Low-voltage ride-through method for doubly-fed wind turbines

Abstract

The invention discloses a low-voltage ride-through method for a doubly-fed induction generator. The method comprises the following steps of: 1) detecting rotor current; 2) comparing a value of the rotor current which is obtained by detection with a reference value, and if the value of the rotor current is greater than the reference value, starting a crowbar circuit; and 3) during starting of the crowbar circuit, starting an emergency variable pitch system so as to realize coordinated control of the emergency variable pitch system and the crowbar circuit. The low-voltage ride-through method for the doubly-fed induction generator has the advantages that: the problem of low stability of the rotating speed of a system caused by turn-on of the conventional crowbar circuit is solved; and by coordinated control of an emergency variable pitch technology and a crowbar technology, during voltage dip, the input mechanical torque of the system is reduced by using a variable pitch technology, and the stability of the rotating speed of the system can be improved.

Description

technical field [0001] The invention relates to a method in the technical field of wind power protection, in particular to a method for low-voltage ride-through of double-fed wind turbines. Background technique [0002] In order to cope with the energy crisis and environmental degradation, countries around the world are actively promoting the development and utilization of renewable energy. Among them, wind power generation has become the focus of scientific research personnel and commercial enterprises. This is because wind energy is a reliable, unlimited, renewable source of electricity supply. The large-scale application of wind power can not only alleviate the energy crisis, but also reduce the environmental problems caused by the use of conventional energy, thereby reducing the emission of carbon dioxide gas. [0003] However, the integration of large-scale wind power into the grid has brought great challenges to grid operation. In order to connect large-scale wind p...

AI Technical Summary

Problems solved by technology

[0008] 1) For long-lasting faults, crowbar technology cannot realize uninterrupted grid-connected operation of double-fed wind turbines

[0009] 2) At the same time, due to the input of the crowbar circuit, the rotor fault current decays rapidly, which deteriorates the stability of the system speed and makes the unit speed rise faster

If the voltage dip fault time is longer, the result will be further deteriorated

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