Purpose

The purpose of this paper is to present a methodology for calculating eddy current losses in the core of a single-phase power voltage transformer, which, unlike a standard power transformer, has an open-type core (I-type core). In those apparatus, reduction of core losses is achieved by using a multipart open-type core that is created by merging a larger number of leaner cores.

Design/methodology/approach

3D FEM approach for calculation of eddy current losses in open-type cores based on a weak AλA formulation is presented. Method in which redundant degrees of freedom are eliminated is shown. This enables faster convergence of the simulation. The results are benchmarked using simulations with standard AVA formulation.

Findings

Results using weak AλA formulation with elimination of redundant degrees of freedom are in agreement with both simulation using only weak AλA formulation and with simulation based on AVA formulation.

Research limitations/implications

The presented methodology is valid in linear cases, whereas the nonlinear case will be part of future work.

Practical implications

Presented procedure can be used for the optimization when designing the open-type core of apparatus like power voltage transformers.

Originality/value

The presented method is specifically adapted for calculating eddy currents in the open-type core. The method is based on a weak formulation for the magnetic vector potential A and the current vector potential λ, incorporating numerical homogenization and a straightforward elimination of redundant degrees of freedom, resulting in faster convergence of the simulation.

中文翻译：

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电力电压互感器开式铁芯的涡流损耗

目的

本文的目的是提出一种计算单相电力变压器铁芯涡流损耗的方法，该变压器与标准电力变压器不同，具有开放式铁芯（I 型铁芯）。在这些装置中，通过使用通过合并大量较精简的磁芯而形成的多部分开放型磁芯来实现磁芯损耗的减少。

设计/方法论/途径

提出了基于弱AλA公式计算开放型磁芯涡流损耗的 3D FEM 方法。示出了消除冗余自由度的方法。这使得模拟能够更快地收敛。使用标准AVA公式的模拟对结果进行基准测试。

发现

使用消除冗余自由度的弱AλA公式的结果与仅使用弱AλA公式的模拟和基于AVA公式的模拟一致。

研究局限性/影响

所提出的方法在线性情况下是有效的，而非线性情况将是未来工作的一部分。

实际影响

所提出的程序可用于设计电力变压器等开放式铁芯设备时的优化。

原创性/价值

所提出的方法特别适用于计算开放型磁芯中的涡流。该方法基于磁矢量势A和电流矢量势λ的弱公式，结合了数值均匀化和直接消除冗余自由度，从而加快了仿真的收敛速度。