Equivalent circuit model building method of transformer iron cores in different structures

Abstract

The invention relates to an equivalent circuit model building method of transformer iron cores in different structures. The equivalent circuit model building method includes steps that: (1) the magnetic field intensity and the magnetic induction intensity of iron core materials are calculated through a Jiles-Atheron model; (2) equivalent circuit models of transformers with different iron core structures are constructed according to the duality principle; and (3) parameters of the equivalent circuit models of the transformers are calculated. According to the equivalent circuit model building method, parameters of the JA model are solved through hysteresis loop data of the iron core materials and serve as input of a duality principle model. The equivalent circuit models capable of calculating excitation characteristic changing of the transformers with different iron core structures on the condition of direct current magnetic bias are built by aid of the duality between a magnetic circuit and currents and can simulate transformer direct current magnetic bias, magnetizing inrush currents, ferromagnetic resonance and the like.

Description

technical field [0001] The invention belongs to the technical field of power system transient simulation calculation, in particular to a method for establishing equivalent circuit models of transformer iron cores with different structures. Background technique [0002] Power transformer is a common electrical equipment, whether in power plants or substations, power transformers of various forms and sizes with different capacities can be seen in operation. A power transformer can convert one level of voltage into another level of voltage, so it can be used to connect power grids of different voltages together to form a complex power grid or a large power system. However, transformers in actual operation often have some abnormal vibration problems: 1) When solar activities frequently cause magnetic storms, the vibration is abnormal. 2) When the single-phase converter station of DC transmission operates with the earth as the loop, the nearby transformers will vibrate abnormall...

AI Technical Summary

Problems solved by technology

However, some abnormal vibration problems often occur in transformers in actual operation: l) When solar activities frequently cause magnetic storms, the vibration is abnormal

2) When the single-phase converter station of DC transmission operates with the earth as the loop, the nearby transformers will vibrate abnormally

There are a large number of harmonics in the excitation current of the transformer after the DC bias occurs, which becomes the harmonic source in the AC system, which will affect the operating performance of the AC protection

The current simulation software is very simplified for the excitation branch of the transformer, and cannot accurately evaluate the influence of DC bias on the transformer

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