Adaptive Suppression Method for Medium and High Frequency Oscillation in Flexible HVDC Transmission System

Abstract

The invention discloses a medium-high frequency oscillation adaptive suppression method of a flexible direct current transmission system. The medium-high frequency oscillation adaptive suppression method first detects the oscillation frequency through an oscillation frequency detection device, and then adjusts the voltage feedforward control link of the flexible direct current converter. Additional band-stop filter parameters for oscillation suppression; the oscillation frequency detection device quickly detects the oscillation frequency based on the frequency distribution characteristics formed by multiple filters according to the three-phase voltage measurement value at the converter outlet; the detection oscillation frequency is given to It is set as the center frequency of the band-stop filter, so that the band-stop filter can quickly track the system oscillation frequency, and then by adjusting the band-stop filter bandwidth and damping ratio and other parameters, the purpose of self-adaptive suppression of medium and high frequency oscillations is achieved. The invention can effectively solve the medium and high frequency oscillation problem of the flexible direct current transmission system.

Description

technical field [0001] The invention belongs to the technical field of direct current transmission, and in particular relates to a medium-high frequency oscillation self-adaptive suppression method of a flexible direct current transmission system Background technique [0002] Flexible DC transmission technology has been widely used in new energy grid connection, asynchronous grid interconnection, and island power supply due to its advantages such as flexible control, low switching loss, no commutation failure, and good output waveform. However, in recent years, high-frequency oscillations have appeared in flexible straight engineering, which has caused certain harm to the safe and stable operation of the system. Aiming at the problem of high-frequency oscillation in the flexible DC transmission system, most of the related researches are aimed at the adjustment of the wide-band impedance characteristics of the converter. The adjustment range is wide, and it cannot be adjusted...

AI Technical Summary

Problems solved by technology

However, in recent years, high-frequency oscillations have appeared in flexible straight engineering, which has caused certain harm to the safe and stable operation of the system.

Aiming at the problem of high-frequency oscillation in the flexible DC transmission system, most of the related researches are aimed at the adjustment of the wide-band impedance characteristics of the converter. The adjustment range is wide, and it cannot be adjusted for specific frequency bands. Moreover, the oscillation detection and suppression lack real-time performance. Therefore, it is necessary to propose a An Adaptive Suppression Method for Medium and High Frequency Oscillations Applicable to Flexible HVDC Transmission Systems

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