Method and device for obtaining admittance model and impedance model of voltage source converter

Abstract

The invention discloses an admittance model and impedance model acquisition method and device of a voltage source converter. The method comprises the steps that multiple converter parameters are acquired; multiple converter control parameters are acquired; a grid-connected system is run, and when the grid-connected system is in a steady state, multiple steady state values of the grid-connected system are collected; based on the multiple converter parameters, the multiple converter control parameters and the multiple steady state values, an admittance model transfer function is obtained, and through the admittance model transfer function, a frequency coupling admittance model and impedance model of the converter when the frequency of a small disturbance signal is fs are obtained. By means of the method, the coupling relationship between sub-synchronization and super synchronization can be considered, the influence of outer loop control is also considered, and the frequency coupling admittance model and impedance model of the converter are obtained based on the obtained small disturbance signal, so that the stability of a power system is accurately analyzed.

Description

technical field [0001] The invention relates to the technical field of power system analysis and control, in particular to a method and device for obtaining an admittance model and an impedance model of a voltage source converter. Background technique [0002] At present, with the development of power electronic technology, power electronic equipment plays an important role in the power system. Especially in recent years, renewable energy power generation based on converters has developed rapidly, and power electronic converters are more and more widely used in power systems. However, the system stability problem caused by the converter is also more prominent. For example, when wind power is connected to the grid, the interaction between the converter and the AC system may cause subsynchronous oscillations, resulting in serious power accidents. [0003] In the related art, in the stability analysis of the oscillation problem related to the converter, the method of impedance...

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Problems solved by technology

However, the current research on the impedance model is mainly the research on the influence of higher frequency harmonic disturbances on the stability of the power system, and there is less research on the case of lower frequencies (several Hz to 2 times the power frequency). There are still some defects in the stability analysis of power system SSR / SSO (SubSynchrous Resonance, Subsynchronous Oscillation, Subsynchronous Oscillation), and it cannot guarantee the stability of the power system

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