Determination method for magnetic hysteresis characteristics and depletion characteristics of transformer in DC magnetic bias state

Abstract

The invention discloses a determination method for magnetic hysteresis characteristics and depletion characteristics of a transformer in a DC magnetic bias state. The determination method comprises the following steps: creating a lamination iron core model; dissecting the lamination iron core model to obtain finite elements; initializing the magnetic vector position and the electric current density of each node; under consideration of a hysteresis effect, combining the finite elements to obtain electromagnetic field result; combining a fixed point technology with a harmonic wave convergence technology to process the obtained magnetic reluctivity data of the magnetic density data; obtaining the data in one-one correspondence to the harmonic wave in sequence to form second harmonic wave data; if the second harmonic wave data do not converge, repeat such steps until the convergent second harmonic wave data is obtained. The determination method is broad in application rage, high in stability, and suitable for large-scale DC magnetic bias analysis, so as to provide important reference for power transformer production and manufacture.

Description

technical field [0001] The invention relates to the field of power transformer operation and manufacture, in particular to a method for determining hysteresis characteristics and loss characteristics of transformers in a DC bias state. Background technique [0002] Affected by various uncontrollable factors, various abnormal working states may appear during the operation of power transformers. Among them, the DC bias phenomenon is a kind of abnormal working state that occurs during the operation of the power transformer. The reason for the DC bias phenomenon of the power transformer is that the power transformer is affected by factors such as solar magnetic storms and high-voltage DC transmission operation modes. The DC component appears in the excitation current of the transformer winding, and the resulting DC magnetic flux makes the iron core quickly enter half-cycle saturation. state, the corresponding excitation current presents a positive and negative half-cycle asymme...

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Problems solved by technology

[0004] Using the traditional harmonic balance finite element method to analyze the nonlinear magnetic field in the laminated iron core of the power transformer, and to study the DC bias problem of the transformer, it needs a large computer memory and is not suitable for large-scale calculations.

Moreover, the premise of this method is that it is impossible to calculate the core loss and its distribution characteristics without considering the hysteresis effect of ferromagnetic materials.

Therefore, when considering the hysteresis effect of ferromagnetic materials, the traditional harmonic balance finite element method is no longer applicable

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