Method for improving low voltage ride through capacity of wind generating set

Abstract

The invention relates to a method for improving the low voltage ride through capacity of a wind generating set. Electric power storage equipment is additionally arranged in a frequency conversion system of the wind generating set and comprises a charging controller and a battery, wherein the battery is connected to a direct current bus of a frequency converter; and the charging controller has the characteristic of quick charging. The electric power storage equipment comprises the working steps of: under a normal operation state of a power grid, if the active power P1 generated by the wind generating set is higher than the active power P2 required by the power grid, introducing the exceeded power deltaP into the electric power storage equipment for storing; in the fault state of the grid, storing the energy of an impulse current into the battery when the impulse current occurs to the direct current bus of the frequency converter at the beginning of a grid failure; and discharging to the power grid by the electric power storage equipment when a power grid voltage restores to 90% of a rated voltage Un so that the active power P1 generated by the wind generating set is in balance with the active power P2 required by the power grid.

Description

technical field [0001] The invention relates to a wind power generation system, in particular to a method for improving the low voltage ride-through capability of a wind power generating set, so as to enhance the stability of power grid operation. Background technique [0002] Wind power is the fastest-growing renewable energy technology in the world in the past decade. With the continuous increase of the single-unit capacity of wind turbines and the continuous expansion of the scale of wind farms, the impact of wind turbines on the power grid has become increasingly serious. When there is a grid failure, the existing protection principle is to immediately disconnect the generator from the grid to ensure the safety of the unit. Once a power grid failure forces a large area of ​​wind turbines to go off the grid due to their own protection, it will seriously affect the operation stability of the power system. Power grid fault is an abnormal operation form of power grid, main...

AI Technical Summary

Problems solved by technology

The disadvantage of this technology is that the large fault current and high voltage are transferred to the crowbar circuit, and the energy is wasted by the energy release resistor, which cannot be used reasonably

[0010] In addition, the current operating mode of wind turbines is that when the active power P1 generated by the wind turbine is greater than the active power P2 required by the grid, P1 is reduced through pitch adjustment to balance it with P2, and rapid pitch changes will occur Mechanical shock increases the failure rate of the unit. At the same time, the power is balanced by changing the pitch, which fails to make full use of wind resources.

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