Method for calculating harmonic wave impedance of alternating current system for direct current transmission

Abstract

The invention provides a method for calculating harmonic wave impedance of an alternating current system for direct current transmission. The method includes the following steps that a node admittance matrix is formed according to a harmonic wave model of a transmission line, a transformer, a generator, a load and a parallel capacitor; nodes to be calculated are placed at the bottom line of the admittance matrix, the current value at the bottom line is set to be 1, and the current values at other lines are set to be 0; node optimizing numbering is conducted on the first n-1 nodes; the node admittance matrix is stored through a sparse technology; the node admittance matrix is solved, and the back substitution does not need to be conducted; a plurality of input files are simultaneously calculated through a parallel calculation method; statistic analysis is conducted according to the batch processing calculation result. According to the method, specific to the characteristic that multiple times of scanning needs to be conducted for calculating the harmonic wave impedance, the improved node optimizing numbering technology and the improved sparse technology are adopted, and therefore the workload for calculating the harmonic wave impedance is reduced, the calculating speed is greatly increased, burdens of operators are relieved, and precious time can be saved.

Description

technical field [0001] The invention is a method for calculating the harmonic impedance of an AC system used for direct current transmission, which belongs to the transformation technology of the method for calculating the harmonic impedance of an AC system used for direct current transmission. Background technique [0002] During the operation of high-voltage direct current transmission, in the high-voltage direct current converter station, the converter, as a nonlinear component in the power system, is the main harmonic source in the converter station, which will generate various harmonics during operation. These harmonic currents are injected into the AC system through the grid side of the converter transformer. If not controlled, it will affect the normal operation of the AC and DC systems. Harmonics and their suppression are one of the key technical issues in HVDC transmission systems. In order to suppress harmonics, a large number of filter devices must be installed i...

AI Technical Summary

Problems solved by technology

[0003] In the past, in the design of the DC transmission system, the equivalent harmonic impedance of the AC system was mostly calculated using the NIMSCAN program of Canada Tessimon Corporation. In engineering use, it was found that the program was too cumbersome in the scanning process, the data conversion was complicated, and the calculation results needed further processing. PSCAD / EMTDC can perform harmonic analysis and AC system impedance equivalents, but it is not suitable for huge systems with thousands of nodes

Simplify a large system with thousands of nodes into a simplified system that retains several important nodes and components to reduce the amount of calculation. However, this will obviously reduce the accuracy of the results, and more importantly, it may ignore some affecting harmonics. Important Factors of Distribution and Resonance Conditions

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