Double-fed wind power generation system

Abstract

The invention discloses a double-fed wind power generation system with a low voltage ride through function. The double-fed wind power generation system can effectively protect a double-fed wind power converter when the voltage of a power grid dips (including three-phase symmetrical short-circuit faults and asymmetrical short-circuit faults of the power grid), simultaneously can reversely send reactive power or active power to the power grid so as to support removal of power grid faults, and continuous running of a double-fed wind driven generator is guaranteed. The double-fed wind power generation low voltage ride through device comprises an active crowbar device and a direct current link chopper device. The active crowbar device is used for protection of rotor overcurrent and overvoltage when the voltage of the power grid dips, effectively avoids impact of the rotor overcurrent and overvoltage on a machine side converter, simultaneously can be quickly disconnected after fault impact is over so as to recover normal control of the double-fed wind power converter, and avoids off-grid running of a whole machine set during the fault ride through period. The direct current link chopper device is used for protection of direct current link overvoltage when power grid faults occur or power grid control is abnormal. When the power grid faults occur, energy of a generator rotor is fed back to direct current link so that direct current link overvoltage occurs, the effective value of the direct current link chopper device reduces direct current link voltage overshoot, and the safety of a converter power unit is guaranteed.

Description

technical field [0001] The invention relates to the low-voltage ride-through operation and control of a megawatt-level wind power generation system when the grid voltage drops, and ensures that the wind power generating set does not run off the grid when the grid fails, so as to meet the low-voltage ride-through requirements promulgated by the State Grid. Background technique [0002] With the continuous increase of wind power installed capacity, the position of wind power in the power system has changed. When the installed capacity of wind power is small, the impact of its operation on system stability can be ignored; when the installed capacity of wind power becomes larger and its proportion in the system increases year by year, the impact of its operation on system stability becomes Can not be ignored. [0003] In order to ensure the safe and stable operation of the power system, some power associations or power grid companies in Europe, North America and Australia have ...

AI Technical Summary

Problems solved by technology

[0006] The double-fed wind turbine currently produced by our factory, because the generator stator is directly connected to the grid, the voltage drop of the grid will cause overvoltage and overcurrent on the rotor side

Although a crowbar protection circuit (passive crowbar) is configured, it is only a protection measure for the inverter when a voltage drop occurs. After the action, it must be stopped, and low voltage ride through (LVRT) cannot be achieved.

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