Method for suppressing low-frequency oscillation of flexible direct-current power transmission system

Abstract

The invention discloses a method for suppressing low-frequency oscillation of a flexible direct-current power transmission system, and the method comprises the steps: collecting and obtaining the low-frequency oscillation generation position information of each monitoring point in a power system, carrying out the data analysis of the collected low-frequency oscillation generation position information, estimating the low-frequency oscillation generation probability, and formulating a low-frequency oscillation suppression strategy. Wide-area centralized or decentralized control of ultralow-frequency oscillation is realized by fully utilizing the rapid adjustment capability of direct current, and the defect of suppression of ultralow-frequency oscillation caused by direct current and modification of parameters of a speed regulator is overcome.

Description

technical field [0001] The invention relates to the technical field of power systems, in particular to a method for suppressing low-frequency oscillation of a flexible direct current transmission system. Background technique [0002] DC transmission is mainly composed of converter stations (rectifier stations and inverter stations), DC lines, power filters on the AC side and DC side, reactive power compensation devices, converter transformers, DC reactors, protection and control devices, etc. Among them, the converter station is the core of the DC transmission system, which completes the conversion between AC and DC. [0003] The development of DC transmission is also limited by some factors. First of all, the converter station of DC transmission is more complex than the substation of AC system, with higher cost and higher requirements for operation and management; 40% to 60% of the DC transmission power; the converter device will generate harmonics on both the AC side and...

AI Technical Summary

Problems solved by technology

Taking the DC transmission grid with a relatively high proportion of hydropower as an example, the prominent negative damping effect of the hydro turbine can easily lead to ultra-low frequency oscillation (oscillation frequency less than 0.1Hz) in the system under certain faults (short circuit fault, DC power boost, etc.). Oscillation sources are difficult to identify one by one, and the oscillation energy cannot be accurately calculated

[0005] Although the DC frequency limiting controller (hereinafter referred to as FLC) has a certain inhibitory effect on the ultra-low frequency oscillation, but when the amplitude of the ultra-low frequency oscillation is smaller than the dead zone of the FLC, the FLC will not function and cannot suppress the ultra-low frequency oscillation

[0006] Secondly, the power grid operator can suppress the ultra-low frequency oscillation by modifying the parameters of the turbine governor, but at the same time it also sacrifices the frequency regulation capability of the power grid

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