# Full-Scale Modeling and FBGs Experimental Measurements for Thermal Analysis of Converter Transformer

## TL;DR

Researchers created a detailed model and used sensors to study how transformer temperatures change under different loads, finding consistent trends and validating results with high accuracy.

## Contribution

A full-scale thermal model of a converter transformer was developed and validated with FBG sensors, revealing detailed temperature behaviors under varying loads.

## Key findings

- Transformer winding temperatures generally increase from bottom to top.
- Internal temperature fluctuations occur within specific sections under load.
- Simulation and experimental results showed a maximum discrepancy of 3.5%.

## Abstract

As the imbalance between power demand and load capacity in electrical systems becomes increasingly severe, investigating the temperature variations in transformers under different load stresses is crucial for ensuring their safe operation. The thermal analysis of converter transformers poses challenges due to the complexity of model construction. This paper develops a full-scale model of a converter transformer using a multi-core high-performance computer and explores its thermal state at 80%, 100%, and 120% loading ratios using the COUPLED iteration method. Additionally, to validate the simulation model, 24 FBGs are installed in the experimental transformer to record the temperature data. The results indicate a general upward trend in winding the temperature from bottom to top. However, an internal temperature rise followed by a decrease is observed within certain sections. Moreover, as the loading ratio increases, both the peak temperature and temperature differential of the transformer windings rise, reaching a peak temperature of 107.9 °C at a 120% loading ratio. The maximum discrepancy between the simulation and experimental results does not exceed 3.5%, providing effective guidance for the transformer design and operational maintenance.