A Method of Subsynchronous Oscillation Suppression Based on Grid-connected Converter Control

Abstract

The invention discloses a method for realizing subsynchronous oscillation suppression based on the control of a grid-connected converter, which includes: collecting the three-phase AC voltage V at the PCC point of the grid-connected converter PCC and current I PCC ; to V PCC and I PCC Perform coordinate transformation to obtain the active and reactive components i of the current in the rotating coordinate system d i q ;according to active current reference value i dref i d and voltage feed-forward control signal to obtain active current control signal E d ;According to the reactive current reference value i qref i q , Additional reactive current command optimization control signal U tcq And the voltage feed-forward control signal to obtain the reactive current control signal E q ; by E q ,E d and θ to obtain the three-phase AC internal potential e abc ; to e abc The switch control signal is obtained after pulse width modulation, so as to suppress the subsynchronous oscillation of the shafting of the adjacent synchronous machine. The invention does not increase the system capacity and does not change the parameters of the PI controller, but only adds a control branch at the reactive current command of the grid-connected converter, improves the electrical damping of the synchronous machine, and increases the effect of suppressing the sub-synchronous oscillation of the synchronous generator.

Description

technical field [0001] The invention belongs to the field of power system stability control, and more specifically relates to a method for controlling the electrical damping of a synchronous machine based on an additional reactive current command of a grid-connected converter. Background technique [0002] The subsynchronous oscillation of the synchronous generator belongs to the system oscillation instability. According to its mechanism, it can be divided into two problems. One is the subsynchronous resonance problem of the power system caused by the series capacitance compensation in the AC transmission system. caused by subsynchronous oscillation problems. Because grid-connected converters respond very sensitively to power and speed changes within the sub-synchronous range. [0003] The suppression of the subsynchronous oscillation of the synchronous generator is mainly to study the electrical damping characteristics of the synchronous generator, and realize the optimiza...

AI Technical Summary

Problems solved by technology

[0007] Aiming at the defects of the prior art, the purpose of the present invention is to realize subsynchronous oscillation suppression by providing an additional reactive current command control based on the grid-connected converter when the electrical distance between the grid-connected converter and the synchronous machine is relatively close. While increasing the system capacity and not changing the parameters of the PI controller, only add a damping compensation branch at the reactive current command of the current loop of the grid-connected converter to improve the electrical damping of the synchronous machine and increase the suppression effect of suppressing the subsynchronous oscillation of the synchronous generator , aiming to solve the technical problems of using synchronous generator speed feedback error and serious lag, unable to effectively invest in the oscillation suppression device in a timely manner, and adding additional suppression equipment to the grid-connected converter to increase the device cost and control complexity

Images