Method for obtaining single-phase double-winding transformer improved pi model considering iron core deep saturation features

Abstract

The invention discloses a method for obtaining a single-phase double-winding transformer improved pi model considering iron core deep saturation features. The method includes the steps of determiningparameters of a transformer through an open-circuit test and a short-circuit test when the transformer works in a non-saturation area, conducting a deep saturation test when an iron core of the transformer works in a saturation area, exciting the iron core to enter a saturation state through an AC / DC hybrid power supply, testing the port apparent incremental inductance under different saturation degrees, calculating the saturation inductance of two excitation branches according to a pi model circuit structure, converting the saturation inductance into excitation curve data, describing the gradual change process of the iron core from initial saturation to deep saturation through the excitation curve data of the saturation section, and establishing the single-phase double-winding transformerimproved pi model considering the iron core deep saturation features according to the data. By means of the single-phase double-winding transformer improved pi model considering the iron core deep saturation features, a basic transformer model can be provided for EMTP type electromagnetic transient software, and the capacity of the model for simulating the transformer deep saturation physical phenomenon is improved.

Description

technical field [0001] The invention relates to the technical field of electric power, in particular to an improved model acquisition method of a single-phase double-winding transformer considering the deep saturation characteristics of an iron core. Background technique [0002] T, Γ and π equivalent circuits (abbreviated as Γ, T, π model) are classic models for simulating single-phase double-winding transformers and have been widely used. Both the T model and Γ model can effectively analyze the transformer steady state and some low frequency transient processes. However, the problem with the T model is that it divides the leakage inductance into two parts, thus losing its physical meaning; the Γ model overcomes this shortcoming, but it believes that the saturation degree of the transformer core is consistent when it is deeply saturated, which is inconsistent with the actual situation, and the single In the phase transformer Γ model, the excitation branch can be connected ...

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Problems solved by technology

[0003] Under the influence of overvoltage, transient impact or DC bias, the iron core of the transformer may enter saturation or even deep saturation state, but the parameters of the classic π model are all measured through transformer open circuit and short circuit tests, and the model parameters when the iron core is saturated are not considered. Therefore, there are large errors in the simulation of electromagnetic transient phenomena involving iron core saturation, such as inrush current, ferromagnetic resonance, geomagnetic induction current, and DC bias

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