Transformer direct-current magnetic bias analogue simulation method based on improved J-A formula in magnetic bias state

Abstract

The invention discloses a transformer direct-current magnetic bias analogue simulation method based on an improved J-A formula in a magnetic bias state, and relates to the field of Jiles-Atherton (J-A) hysteresis simulation modeling in the direct-current magnetic bias state. The method comprises the following steps: firstly, carrying out derivation correction on a J-A formula in a normal excitation state; based on the introduction of a direct-current component, improving a hysteresis-free magnetization curve and a differential expression of magnetization intensity of a J-A theory in a direct-current magnetic bias state according to a total current law and an energy conservation principle, correcting a containment coefficient k of the J-A theory, and providing an analogue simulation method;writing a simulation program in an S-function module of MATLAB (Matrix Laboratory) by using an M language; under the condition that winding end voltage and direct current are known, adopting simulinkto simulate an excitation current value and a hysteresis curve. The error between the excitation current value and the calculated value of the transformer direct-current magnetic bias model established based on the improved J-A formula is smaller. The hysteresis curve shape conforms to the character that the hysteresis curve of the single-phase transformer is similar to the step shape. The magnetization characteristic of the ferromagnetic material in the magnetic bias state can be better described.

Description

technical field [0001] The invention relates to the field of Jiles-Atherton (J-A) hysteresis simulation modeling in a DC bias state, in particular to a transformer DC bias simulation method based on the improved J-A formula in a bias state. Background technique [0002] Since there are more and more DC bias incidents of transformers along the line caused by subway operation and HVDC transmission, it is imminent to study the phenomenon of DC bias. DC bias refers to the occurrence of DC components in the transformer windings, which forces the magnetic flux curve of the transformer core to shift, thus bringing many adverse effects to the transformer and power system. The focus of the research on the DC bias phenomenon of transformers is to analyze the magnetization characteristics of its iron core. The Jiles-Atherton theory, which belongs to the category of semi-macroscopic magnetization theory, has clear physical meaning, fewer parameters, and convenient description of hystere...

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Problems solved by technology

[0040] In order to solve the problem that the transformer DC bias model based on the existing Jiles-Atherton (J-A) theory has relatively large errors, the present invention only includes AC components and cannot describe the hysteresis curve in the bias state. Complete and other defects, established a J-A hysteresis formula suitable for the bias state, and based on this, proposed a simulation method for simulating the DC bias phenomenon of transformers

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