Doubly-fed wind generator low voltage ride through method

Abstract

The invention provides a doubly-fed wind generator low voltage ride through method. The method specifically comprises the steps that the limit amplitude value output is conducted on the negative sequence component of rotor voltage according to the maximum controllable rotor voltage of a converter; after the limit amplitude value output is conducted, a grid-side converter operates on the basis of the maximum limit amplitude value of the given current, partial differential voltage energy between the negative sequence component of the rotor voltage and the negative sequence control voltage part of a machine-side converter is input into a power grid through the grid-side converter as far as possible; in addition, the partial differential voltage energy is released through a chopper device; after the power grid voltage is recovered, a converter of a doubly-fed draught fan is switched to the normal power control, and normal stable operation of the power grid is facilitated. According to the doubly-fed wind generator low voltage ride through method, the safety of the doubly-fed wind power converter can be effectively ensured when deep asymmetric short circuit faults occur, continuous operation of a doubly-fed wind generator can be ensured in the breakdown period, low voltage ride through is successfully achieved, and active power and reactive power are poured into the power grid in the falling process.

Description

technical field [0001] The invention relates to a low-voltage ride-through method, in particular to an operation and control method for low-voltage ride-through of a megawatt-level wind power converter when the voltage depth of the power grid drops asymmetrically, so as to ensure that the wind power generating set does not run off-grid when the power grid fails, 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 p...

AI Technical Summary

Problems solved by technology

[0006] For the doubly-fed wind power generator produced by the existing technology, since the stator of the generator is directly connected to the power grid, the voltage drop of the power grid will cause overvoltage and overcurrent on the rotor side

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

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