Alternating current fault control method and control system for doubly-fed wind power hybrid direct current sending-out system

Abstract

The invention relates to a doubly-fed wind power hybrid direct current sending-out system alternating current fault control method and control system, an active power outer ring is transformed and optimized, when an alternating current fault occurs, an actual power instruction value of a wind generating set can quickly follow the grid-connected point output power of the wind generating set, and when the alternating current fault is cleared, the actual power instruction value of the wind generating set can quickly follow the grid-connected point output power of the wind generating set. The actual power instruction value of the wind generating set is gradually recovered to the power instruction value before the fault at a certain slope, and smooth processing is carried out on switching between a low-voltage fault ride-through link and a conventional active power control link, so that the wind generating set can stably and gradually recover output after the fault is cleared, and the power utilization rate of the wind generating set is improved. The power impact on the MMC is reduced, sufficient adjustment time is reserved for the MMC, and the phenomena that the voltage of the sub-module rises and serious overvoltage occurs on the direct current side and the alternating current side due to the fact that serious power surplus occurs in the MMC in the alternating current fault recovery period are avoided.

Description

technical field [0001] The invention relates to the technical field of hybrid direct current transmission, in particular to a control method and control system for an alternating current fault of a doubly-fed wind power hybrid direct current transmission system. Background technique [0002] In the context of the global depletion of fossil energy, increasing the use of renewable energy is an important means of energy conservation and emission reduction. From a global perspective, wind power generation is the most mature in the development and utilization of renewable energy, and has the most conditions for large-scale development. . [0003] my country's wind energy resources are generally very rich, but wind energy is mainly concentrated in the northwest and northeast regions, while the power load is mainly concentrated in the central and eastern regions. Hybrid DC transmission technology is a new transmission method that combines conventional DC transmission technology an...

AI Technical Summary

Problems solved by technology

However, during the fault period, the output power of the wind farm is blocked, and the active power controller will be saturated without any processing. jump, the power rises rapidly and overshoots, resulting in a power surplus of the low valve group MMC, the voltage of the sub-module rises, and overvoltage occurs on both the DC side and the AC side, causing damage to the equipment and the high voltage of the grid-connected point of the wind farm, which causes the wind turbine to trip. net risk

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