Use Performance and Management of Biodegradable Fluids as Transformer Insulation

Abstract

In recent years, the use of biodegradable fluids as liquid insulation for distribution and power transformers is spreading. The main biodegradable fluids used are natural and synthetic esters, although biodegradable hydrocarbons have been recently proposed. Biodegradable fluids have a much lower environmental impact than mineral oil, limiting the risk of soil contamination in leaks, which makes them a suitable solution for applications such as offshore transformers or railway transformers. Additionally, these fluids have a higher flash point than conventional mineral oils, which dramatically reduces the risk of fire and collateral damage derived from explosion and fire. Despite these advantageous factors, there are still some aspects that hinder the broadening of their use, such as the difference in thermal properties or the lack of accepted maintenance procedures for transformers that use them as liquid insulation. This paper presents the current status of biodegradable insulating fluids, analyzing some of their properties and discussing the aspects that are still to be investigated in order to make them a real alternative to petroleum-based fluids. ; Part of the work was performed during secondments and short visits between University of Valle, University Carlos III of Madrid and University of Cantabria executed in the framework of the BIOTRAFO project "Raising knowledge and developing technology for the design and deployment of high-performance power transformers immersed in biodegradable fluids", H2020-MSCA-RISE-2018- 823969, 2019-21. This project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 823969. Also, we acknowledge the support of the Spanish Ministry of Science and Innovation by means of the National Research Project Asset management of biodegradable-fluid-based transformers (PID2019-107126RB-C21/AEI/10.13039/501100011033 and PID2019-107126RB-C22/AEI/ 10.13039/501100011033).