Stabilization control method of VSC-HVDC power transmission system

Abstract

The invention discloses a stabilization control method of a VSC-HVDC power transmission system. The stabilization control method comprises a virtual resistance-inductance impedance stabilization control part, an output current feedforward control part, and a voltage current double-loop control part According to the virtual resistance-inductance impedance stabilization control, equivalent output impedance of a rectification station converter is corrected to be positive resistance, the damping of the system is enhanced, and the stability of the system is effectively improved, and the direct current side oscillation of the VSC-HVDC power transmission system is inhibited. According to the output current feedforward control, influences of receiving end load power abrupt changes on direct current busbar voltage are reduced, and the transient response performance of the system is improved. A direct current voltage outer ring adopts proportional plus integral control, and is used to track a direct current voltage instruction in an astatic way, and a grid-connected current inner ring adopts feedforward decoupling control under synchronous rotation coordinates, and then relatively low grid-connected current aberration is guaranteed. The stabilization control method is used for the control of the rectification station converter of the VSC-HVDC power transmission system, and the direct current side oscillation of the VSC-HVDC power transmission system is effectively inhibited, and the dynamic performance of the inversion station converter cannot be affected.

Description

Stability control method for VSC-HVDC power transmission system technical field The invention relates to the control field of a VSC-HVDC power transmission system, in particular to a stable control method for a converter of a rectification station in the VSC-HVDC power transmission system. Background technique The VSC-HVDC transmission system has the advantages of being able to supply power to passive networks, independent control of active and reactive power, and no risk of commutation failure. Network power supply and other occasions. However, the VSC-HVDC power transmission system is a cascaded system composed of converters in the converter station through DC transmission cables, and the converters in the inverter station will behave as constant power loads, and the negative incremental impedance characteristics of constant power loads will lead to system The dynamic characteristics become worse, and even oscillation instability occurs, which seriously restricts the pr...

AI Technical Summary

Problems solved by technology

The rectifier station converter using traditional virtual resistance stabilization control will fail to suppress the DC side oscillation of the VSC-HVDC transmission system. The reason is that the equivalent output impedance of the rectifier station converter deteriorates to negative resistance outside the voltage control bandwidth, thereby reducing the System damping

Therefore, the traditional virtual resistance stabilization control is not suitable for VSC-HVDC transmission systems where the converter voltage control bandwidth is low.

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