Method for measuring harmonic interaction strength of AC side of inversion station of multi-fed DC system

Abstract

The invention proposes a method for measuring harmonic interaction strength of an AC side of an inversion station of a multi-fed DC system. The method comprises the steps of 1) determining harmonic order k of a to-be-researched inversion station in the multi-fed DC system, and assuming total number of the to-be researched inversion station as n; 2) calculating k-order harmonic self-impedance Z<ii(k)> of a conversion bus i in a to-be-researched system, k-order harmonic mutual impedance Z<ij(k)> between the conversion bus i and a conversion bus j and equivalent harmonic impedance z<i(k)> and z<j(k) after Thevenin equivalent on an AC system connected with the conversion bus i and the conversion bus j, wherein I is equal to 1, 2 until n, and j is equal to 1, 2 until n; and 3) calculating a harmonic interaction effect factor HEIIF<ji(k)>, wherein the size of the HEIIF<ji(k)> and the interaction effect intensity of direct current i on direct current j are in positive proportion relation. TheHEIIF<ji(k)> is rapidly obtained by a harmonic impedance matrix, and reference is provided for estimating intensity of harmonic interaction effect of the AC side between inversion stations in the multi-fed DC system.

Description

technical field [0001] The invention proposes a method for measuring the intensity of harmonic interaction on the AC side between inverter stations of a multi-infeed DC system, and belongs to the technical field of power system analysis. Background technique [0002] When multiple DC transmission points are placed on the same AC system, the resulting DC transmission system is called a Multi-Infeed Direct Current System (Multi-Infeed Direct Current System, [0003] MIDC). MIDC is a multi-coupling system. When multiple converter stations are connected to the same or multiple AC buses with close distances, interaction may occur. With the development of DC projects in China and the continuous expansion of DC capacity scale, the problem of harmonic interaction will become increasingly prominent, such as causing malfunction or refusal of converter protection, causing commutation failure in DC transmission system, and introducing new Harmonic sources cause harmonic pollution to t...

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Problems solved by technology

[0006] MISCR), multi-infeed interaction factor (MIIF), etc. all measure the interaction from the perspective of the fundamental wave, and lack an index that directly reflects the closeness of the harmonic connection between each circuit and DC.

However, the ratio of the change of the corresponding harmonic current injected into the AC system connected to each DC circuit when the AC filter is switched through the electromechanical transient or electromagnetic transient simulation can roughly measure the magnitude of the harmonic interaction, but this method It is necessary to conduct experiments on the possible AC filter switching combinations of each converter station under various conditions, which requires a large amount of work and takes a long time to calculate

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