A low-voltage ride-through reactive power control method for wind turbine full-power converters

Abstract

The invention relates to a reactive power control method for low voltage ride-through of a full-power converter of a wind generation set. The reactive power control method includes: at the moment when the wind generation set enters low voltage ride-through, freezing a reactive power command Qref received by the full-power converter, and resolving a corresponding reactive current value Id'; when the Qref refers to an inductive reactive power command, computing a reactive current value Id, wherein reactive current Ireactive executed actually by the converter satisfies that Ireactive=Id; when the Qref refers to a capacitive reactive power command, computing another reactive current value Id so as to obtain another reactive current Ireactive executed actually by the converter, wherein the Ireactive satisfies that Ireactive=-Max (Id', Id). The reactive power control method has the advantage that seamless switching from steady-state operation of the set to grid voltages slag and low voltage ride-through of the set and from low voltage ride-through of the set to recovery of grid voltage steady-state operation is achieved under the condition that the wind generation set provides reactive power.

Description

technical field [0001] The invention relates to the field of wind power control, in particular to a method for controlling low-voltage ride-through reactive power of a full-power converter of a wind turbine. Background technique [0002] With the increasingly severe energy crisis and the rapid development of renewable energy technologies, the global wind power installed capacity is increasing at an average annual rate of more than 20%, and wind power has become an industry with a considerable scale. By the end of 2013, the cumulative installed capacity of wind power in the world had reached 318 million kilowatts, and more than 300 wind farms had been installed. A large part of the development and operation and maintenance costs of wind farms is used for automatic reactive power compensation devices. Taking a wind farm in Ningxia as an example, the monthly power consumption of MCR-type SVC can reach 200,000 kilowatts. Considering the high cost of electricity consumption of a...

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Problems solved by technology

[0004] The method mentioned in this patent does not clearly explain the control method of the reactive power of the converter during the period of low wear-out, nor can it achieve steady-state operation when the grid voltage drops during the period when the wind turbine generator generates reactive power until the grid voltage drops. and the seamless switching from the low wear-through of the unit to the recovery of steady-state operation of the grid voltage

[0005] It can be seen that the above-mentioned existing full-power wind turbine grid-connected converter low-voltage ride-through control method obviously has inconvenience and defects in use, and needs to be further improved.

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