Method for solving equivalent impedance frequency characteristic of HVDC transmission system converter

Abstract

The invention discloses a method for solving the equivalent impedance frequency characteristic of an HVDC transmission system converter under various operating conditions and failure conditions, whichcomprises the following steps: according to the fundamental component of voltage between phases of converting buses and the DC component of direct current, and a trigger angle instruction of a DC control system, calculating the actual trigger angle of each converting valve and the delay angle of flow of the converting valve in the converter, and the actual phase-change angle when two phases are converted; then calculating a three-phase voltage switching function and a three-phase current switching function; and by the subharmonic components of the three-phase voltage switching function and the three-phase current switching function, and the equivalent harmonic impedance of an AC network and a DC network, calculating the equivalent harmonic impedances at the AC side and the DC side of theconverter. The method can realize the calculation of the equivalent harmonic impedances at the AC side and the DC side of the converter under various AC operating conditions and failure conditions, reduce the calculation amount and meet the demand on precision in engineering application.

Description

technical field [0001] The invention relates to a method for solving the equivalent impedance frequency characteristics of a converter in a high-voltage direct current transmission system in the field of electric power systems, and in particular relates to a method for a high-voltage direct current transmission system under various normal operating conditions and asymmetric faults in the AC system. A method for solving the frequency characteristics of the equivalent impedance on the AC and DC sides of the converter. Background technique [0002] With the wide application of HVDC transmission system, the impact of the impedance-frequency characteristics of the converter on the AC system has attracted increasing attention. Studies at home and abroad have shown that with specific parameters, the equivalent harmonic impedance of the converter may cause harmonic resonance in the system, thereby amplifying the harmonics in the AC-DC system and leading to instability in the HVDC tr...

AI Technical Summary

Problems solved by technology

However, when an asymmetrical fault occurs in the AC system, the change of the topology of the AC system and the asymmetric operation state of the converter will change the equivalent impedance frequency characteristics of the converter, which may cause harmonics to occur in the original system during the fault. resonance

At present, there are no relevant research results at home and abroad

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