A low-voltage ride-through control method and system device of a doubly-fed wind power generating set

Abstract

A low-voltage ride-through control method and system device for a doubly-fed wind power generating set. When the grid voltage drops, the crowbar is reduced by switching different numbers of energy-consuming resistors by IGBTs in the crowbar circuit device according to the degree of the grid drop. The reactive power absorbed when the device is put in and cut out, thereby reducing the reactive power fluctuation when the crowbar device is put in and cut out, to realize the low-voltage ride-through function of the fan. The IGBT in the crowbar device is turned on when needed to protect the converter and bypass the motor; when the fault is removed, it can be turned off again to cut the crowbar circuit from the motor circuit, so that the wind turbine can quickly Transfer to the power generation state to help the unit realize the function of low voltage ride through. The control is simple and reliable, which can ensure the safe and reliable low-voltage ride-through of the wind turbine, and adopts an offline UPS power supply device, which increases reliability and reduces costs compared with online UPS.

Description

technical field [0001] The invention relates to a control method and device for power transmission and distribution, in particular to a control method and system device for the low-voltage ride-through function in a doubly-fed wind power generation system; it belongs to the technical field of wind power generation. technical background [0002] The number and capacity of grid-connected wind turbines are increasing day by day, and the proportion of wind power in the power system is increasing. The safe and reliable operation of grid-connected wind turbines has become crucial. The power quality and low voltage ride-through function of grid-connected wind turbines are important And the hard indicators of the owner and the evaluation fan. If the low-voltage ride-through is not handled properly, it will cause large-scale shutdown of wind turbines, cause a huge impact on the power grid, and even lead to the collapse of the power grid. [0003] From the perspective of the wind tur...

AI Technical Summary

Problems solved by technology

This crowbar circuit can only realize the protection of the converter, and cannot complete the low-voltage ride-through of the wind turbine

[0007] This kind of crowbar circuit device cannot realize low-voltage ride-through, because the thyristor cannot be turned off by itself, and can only be turned off by relying on the reverse of the external circuit.

[0008] In addition, the switching of the crowbar circuit device will absorb a large amount of reactive power from the grid, which will cause large fluctuations in reactive power, which is not conducive to the recovery of the grid. Power will degrade the grid

[0009] At present, some circuit devices used to realize the low voltage ride-through function of the fan system do not take into account the power supply of the equipment during the grid voltage drop during the design process. As a result, the power supply device supporting the low-voltage ride-through operation of the equipment cannot supply power normally, resulting in the failure of the low-voltage ride-through function of the unit.

[0010] In the design process of some manufacturers, the power supply of the equipment still needs to be operated during the grid voltage drop, and an online UPS is selected. After the online UPS is turned on, the inverter is always in the working state, so there is no interruption time when the mains power is abnormal and the battery is discharged. , that is, 0 interruption, but the online UPS adds a new fault point when the fan is running normally, which is not good for the safe and reliable operation of the fan, and the online UPS is expensive

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