Three-phase transformer electromagnetic transient low-and-medium frequency modeling method and system

Abstract

The invention discloses a three-phase transformer electromagnetic transient low-and-medium frequency modeling method. The method comprises the steps of selecting iron core joints as magnetic circuit division points of a transformer model, and partitioning a transformer; building a magnetic circuit equivalent model according to magnetic conductive features of materials inside the transformer of allpartitioned areas and the spatial distribution of all parts of the transformer; conducting classifying according to physical properties represented by all magnetic resistance elements, establishing acircuit model according to relevant parameters and electromagnetic duality principles of the elements and conducting simplifying according to a topological connection relation; adopting a dynamic loss model according to loss characteristics of magnetic conductive materials of the transformer to simulate the loss of a transformer iron core; combining the circuit model and the dynamic loss model, wherein the combined model is used for simulating nonlinear excitation and loss features of the transformer iron core; calculating the parameters of the circuit part of the transformer, and adopting alinear transformer model for simulation; connecting the combined model for representing the transformer iron core transient characteristics to the low-voltage side of the linear transformer model; calculating the parameters of the transformer.

Description

technical field [0001] The invention relates to the technical field of transformer modeling, and more specifically, to a modeling method and system for a three-phase transformer electromagnetic transient mid-low frequency model. Background technique [0002] As one of the most important power transmission and transformation equipment in the power system, the transformer is responsible for the collection, distribution and measurement of electric energy. With the wide application of UHVDC transmission technology, the transient characteristics of transformer cores under AC-DC hybrid excitation conditions have received increasing attention. In addition to the normal operation of the transformer and the changes caused by the load increase or decrease during the operation process, the abnormal electromagnetic transient process of the transformer at low frequency mainly includes DC bias and excitation inrush current. The main cause of DC bias is the (static quasi) DC injected into...

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Problems solved by technology

[0006] The present invention provides a method and system for modeling a three-phase transformer electromagnetic transient mid-lo

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