Measuring and distinguishing method and system for impedance model of electric power system

Abstract

The invention discloses a measuring and distinguishing method and system for an impedance model of an electric power system. The measuring and distinguishing method comprises the following steps thata port power frequency voltage and a port power frequency current are adjusted to set a stable-state working point, and a preset signal harmonic interference source is additionally arranged in an equipment port; the voltage and the current of the equipment port are collected, power frequency phasors and harmonic wave phasors of the voltage and the current are calculated through Fourier analysis; aworking condition row vector is calculated and obtained according to the power frequency voltage and current phasors, and an operating working condition is changed to obtain different coefficient rowvectors; a coefficient matrix is obtained according to the different coefficient row vectors and expanded, and a column vector is constructed; and equipment parameters are solved according to the expanded coefficient matrix and the column vector to obtain the impedance model of equipment. According to the measuring and distinguishing method, accurate calculation of the impedance model of the equipment under the situation that the operating working condition is changed constantly is effectively achieved, and the stability of the electric power system is effectively improved.

Description

technical field [0001] The invention relates to the technical field of power system analysis and control, in particular to a method and system for detecting and determining an impedance model of a power system. Background technique [0002] In recent years, clean and renewable energy generation technologies such as wind power and photovoltaics based on power electronic converters have developed rapidly, and the proportion of power electronic equipment in the power system has greatly increased. The access of a high proportion of power electronic equipment increases the instability factors of the power system, and correspondingly brings challenges to the stability analysis. [0003] To evaluate the stability of power systems with high power electronics, the method of impedance model can generally be used. Impedance model analysis method is an accurate and effective method. This method first models the impedance of each power equipment in the power system, and then converts th...

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Problems solved by technology

[0004] However, as a small signal model, the size of the equipment impedance model is closely related to its operating conditions, that is, if the power frequency voltage and current at the grid-connected point port change, the impedance model of the equipment will also change accordingly, and this change is non-linear

Therefore, when the operating conditions are constantly changing, if a constant impedance model is used to analyze the stability of the system, it may cause large errors

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