Flexible DC power transmission system and oscillation suppression method thereof

Abstract

The invention provides a flexible direct-current power transmission system and an oscillation suppression method thereof. The method comprises the following steps: establishing a nonlinear model of a preset converter in the flexible direct-current power transmission system; the nonlinear model comprises a phase-locked loop model and a direct-current voltage outer loop model; then, based on the nonlinear model, feedback output power of the preset converter is obtained, the preset converter is controlled to output according to the feedback output power, oscillation suppression of the flexible direct-current transmission system is achieved, and the problem that in an existing related scheme, modeling of a voltage source converter of the flexible direct-current transmission system is insufficient under the weak power grid condition is solved; the oscillation and instability mechanism of the voltage source converter is not clear, and the oscillation and instability of the voltage source converter of the flexible direct current power transmission system cannot be suppressed.

Description

technical field [0001] The invention relates to the technical field of data processing, in particular to a flexible direct current transmission system and an oscillation suppression method thereof. Background technique [0002] Flexible DC transmission technology is an emerging power transmission technology, which consists of a converter station and a DC transmission line. The traditional DC transmission system uses a phase-controlled converter (Line Commutated Converter, LCC). Although it has a large transmission capacity and safe operation, there are problems such as commutation failure, large reactive power consumption, and inability to operate on a weak grid. With the rapid development of the power electronics industry, the flexible DC transmission technology based on the voltage source converter (VSC) overcomes the above problems, and the flexible DC transmission technology based on the voltage-source converter (VSC) is not affected by the strong or weak grid , there i...

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Problems solved by technology

[0004] In this regard, this application provides a flexible direct current transmission system and its oscillation suppression method to solve the problem of insufficient modeling of the voltage source converter of the flexible direct current transmission system under the condition of weak grid in the existing related schemes, which leads to the oscillation and instability of the voltage source converter. The stability mechanism is not clear, and it is impossible to suppress the oscillation and instability of the voltage source converter of the flexible direct current transmission system

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