Oria Carmela, Carrascal Isidro, Ferreño Diego, Fernández Inmaculada, Ortiz Alfredo
Electrical and Energy Department, University of Cantabria, Spain.
Laboratory of Science and Engineering of Materials, University of Cantabria, Avenida Los Castros, s/n, Santander 39005, Spain.
Data Brief. 2021 Apr 2;36:107031. doi: 10.1016/j.dib.2021.107031. eCollection 2021 Jun.
The solid insulation in the windings of power transformers, which generally consists of oil-impregnated thin paper, is one of the key elements for the performance and durability of these electrical machines. Insulation paper is subjected to static and dynamic forces of electromagnetic origin, in combination with high temperatures and chemical reactions, during the operating life of a power transformer. The mechanical properties of the cellulosic insulation are relevant parameters because its breakage could result in the electric failure of the transformer. Indeed, paper manufacturers usually provide values of the tensile strength and elongation at breakage of the insulating paper in its two principal material directions, the MD (machine direction) and CD (cross-direction). However, paper is a highly anisotropic material and its material properties evolve as the paper insulation ages. The paper insulation in an operating transformer is subjected to a multiaxial stress state field including compressive and shear stresses. This article reports experimental data on the tensile and compressive mechanical properties of two types of paper, plain Kraft and crepe paper, typically used as insulation in power transformers, under different ageing states (which were induced through accelerated thermal ageing and quantified by means of the degree of polymerisation). These data could be reused for several purposes. They can improve the current understanding of the mechanical response and degradation processes of the cellulosic insulation in power transformers, and give some reference values that can be compared with others obtained in the factory by manufacturers. In the field of engineering failure analysis, those values could be reused for the assessment of mechanical failure of paper materials used in power transformers, see [1].
电力变压器绕组中的固体绝缘通常由浸油薄纸组成，是这些电机性能和耐久性的关键要素之一。在电力变压器的运行寿命期间，绝缘纸会受到电磁源产生的静态和动态力，同时还伴随着高温和化学反应。纤维素绝缘的机械性能是相关参数，因为其破损可能导致变压器的电气故障。实际上，纸张制造商通常会提供绝缘纸在其两个主要材料方向，即纵向（MD，机器方向）和横向（CD，交叉方向）的拉伸强度和断裂伸长率值。然而，纸张是一种高度各向异性的材料，其材料性能会随着纸张绝缘老化而变化。运行中的变压器中的纸张绝缘会受到包括压缩应力和剪切应力在内的多轴应力状态场的作用。本文报告了两种通常用作电力变压器绝缘的纸张，即普通牛皮纸和皱纹纸，在不同老化状态（通过加速热老化诱导并通过聚合度进行量化）下的拉伸和压缩机械性能的实验数据。这些数据可用于多种目的。它们可以增进目前对电力变压器中纤维素绝缘的机械响应和降解过程的理解，并给出一些可与制造商在工厂获得的其他数据进行比较的参考值。在工程失效分析领域，这些值可用于评估电力变压器中使用的纸张材料的机械失效，见[1]。
