Purpose

Using appropriate solution techniques for transformer inrush current transient study is of great prominence owing to the inevitable inclusion of differential equations leading to complicated analysis procedures. This study aims to propose an analytical-numerical method to accurately analyze the three-phase three-limb core-type transformer inrush current in different cases considering the nonlinear behavior of the iron core.

Design/methodology/approach

The proposed method focuses on acquiring equations for inrush current and also the magnetic core flux by the application of a simulation-based iterative approach. In this regard, multiple integral equations are solved taking the time intervals into account. Then several derivations and integrations of matrix terms are substituted into the obtained results so as to simplify the solution process.

Findings

The method provides notable enhancements in computation time and also excellent qualities of accuracy compared with conventional numerical methods.

Practical implications

The proposed method is simulated for two three-phase transformers via MATLAB software. The obtained simulation results have been also compared with experimental tests.

Originality/value

Actually, the analytical-numerical method is capable of computing higher number of iterations in a shorter time efficiently, while making use of the conventional numerical procedures may not result in expected convergences. The simulation results of the proposed analytical-numerical technique illustrate a close agreement with the experimental test, and hence, verify the method preciousness.

中文翻译：

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一种新颖，精确的解析数值方法用于三臂电力变压器浪涌电流建模

目的

由于不可避免地包含了导致复杂分析程序的微分方程，因此使用适当的解决方案技术进行变压器浪涌电流暂态研究非常重要。本研究旨在提出一种分析数值方法，以考虑铁芯的非线性特性，在不同情况下准确地分析三相三臂铁心型变压器的涌入电流。

设计/方法/方法

所提出的方法着重于通过基于仿真的迭代方法的应用来获取涌入电流和磁芯通量的方程式。在这方面，考虑时间间隔求解多个积分方程。然后，将矩阵项的几个导数和积分代入获得的结果中，以简化求解过程。

发现

与传统的数值方法相比，该方法显着提高了计算时间，并提供了极好的准确性。

实际影响

通过MATLAB软件对两台三相变压器进行了仿真。获得的仿真结果也已与实验测试进行了比较。

创意/价值

实际上，解析数值方法能够在较短的时间内有效地计算出更多的迭代次数，而使用常规数值过程可能不会导致预期的收敛。所提出的解析数值技术的仿真结果与实验测试吻合得很好，从而证明了该方法的价值。