Stable control method for inhibiting voltage oscillation of flexible DC power transmission system

Abstract

The invention relates to a stable control method for inhibiting voltage oscillation of a flexible DC power transmission system. The method is characterized by comprising that an axis-d control channeland / or an axis-q control channel are / is provided with an AC voltage stabilizer in the outer ring of a flexible DC converter station control system in the flexible DC power transmission system; a gaincoefficient and an output amplitude limit value of the AC voltage stabilizer are determined; an output current compensation value of the AC voltage stabilizer after that the gain coefficient and output amplitude limit value are determined is obtained, and added to an original reference current in the outer ring of the flexible DC converter station control system to obtain a reference current in the outer ring of the flexible DC converter station control system; and the reference current is output to the inner ring of the flexible DC converter station control system, and voltage oscillation ofthe flexible DC power transmission system is inhibited. The method can be widely applied to the field of flexible DC power transmission.

Description

technical field [0001] The invention relates to a stable control method for suppressing voltage oscillation of a flexible direct current transmission system, belonging to the field of flexible direct current transmission. Background technique [0002] The flexible direct current transmission technology (high voltage direct current, HVDC) based on the modular multilevel converter (MMC) has developed rapidly in recent years due to its superior performance. The bipolar transistor (Insulate-Gate Bipolar Transistor, IGBT) converter station has the advantages of convenient expansion and boosting, no dynamic and static voltage equalization problems of devices, good harmonic characteristics of AC voltage, and low high-frequency electromagnetic interference. The AC grid provides voltage and reactive power support, and has the function of inter-regional asynchronous interconnection of the grid. The flexible DC project has gradually developed from the initial two-terminal project to t...

AI Technical Summary

Problems solved by technology

The above two control methods can effectively control the AC voltage when the strength of the AC grid is high. However, when the AC grid system connected to the soft DC converter station is weak, the single control method may not be able to realize the AC voltage. stable control, there is an oscillation phenomenon

For example, after the low-frequency oscillation of the generator set in the large AC power grid, low-frequency oscillation may also occur in the power of the entire network. If the flexible DC converter station cannot provide effective positive damping characteristics, it may follow the low-frequency oscillation of the large power grid. In some cases, it may It will also worsen the low-frequency oscillation and increase the amplitude of the oscillation

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