Distribution and Optimization of Temperature-stress Field of Epoxy Solid Sealed High-capacity High-frequency Transformer

被引：0

作者：

Li, Weiguo ^{[1
]}

Chen, Binhao ^{[1
]}

Zhao, Guoliang ^{[1
]}

Qiao, Guangyao ^{[1
]}

Jin, Yanjiao ^{[1
]}

Xu, Yunfei ^{[1
]}

机构：

[1] State Key Laboratory of Advanced Power Transmission Technology, State Grid Smart Gird Research Institute Co., Ltd.), Beijing

来源：

Gaodianya Jishu/High Voltage Engineering | 2024年 / 50卷 / 09期

关键词：

elastic modulus; epoxy resin; high; high-frequency transformer; low temperature impact; stress distribution;

D O I：

10.13336/j.1003-6520.hve.20240765

中图分类号：

学科分类号：

摘要：

The high-frequency transformer (HFT), sealed with epoxy material for overall insulation, effectively reduces equipment volume and improves power density. However, uneven temperature distribution within the large-capacity HFT can lead to concentrated thermal stress in the epoxy resin, resulting in machine cracking and insulation failure. This study focuses on a 10 kV high-voltage large-capacity epoxy-sealed HFT as the research subject. A temperature simulation model and stress calculation model have been developed to determine the thermal stress distribution of the HFT under rated operating conditions. The thermal stress is primarily concentrated in the epoxy layer between the iron core and winding. A method for reducing local thermal stress is proposed by enhancing the thermal conductivity of epoxy resin through material modification in order to decrease the hot spot temperature of the HFT, and the stress in epoxy resin between iron core and winding can be reduced, thereby increasing safety factor from 0.965 to 1.035. Two measures are taken,such as increasing the glass fiber reinforced materials and stress buffer layer, thus, the modulus of elasticity of the encapsulated structure is greatly reduced, the maximum tensile force inside is lowered, and the safety coefficient is increased from 1.035 to 2.691, which guides the structural design of large-capacity epoxy encapsulated high-frequency transformers. A 10 kV/200 kVA prototype is developed to perform validation through −30~120 ℃ high and low temperature impact tests, and its crack resistance performance and effectiveness of reducing thermal stresses methods are verified. © 2024 Science Press. All rights reserved.

引用

页码：3978 / 3987

页数：9

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