Nikola Tesla Institute
Dr. Jelena Lukić
Development of green technology to mitigate power transformer failures induced by elemental sulphur and change current hazardous practice in transformer oil regeneration - GreenCleanS Project / 3PINT and related innovative technologies as permanent solution to mitigate corrosive sulphur in power transformers / Aging Tests of Alternative Insulating Liquids
ABSTRACT: Development of green technology to mitigate power transformer failures induced by elemental sulphur and change current hazardous practice in transformer oil regeneration - GreenCleanS Project
The main idea of GreenCleanS project is to introduce new technology for the removal of elemental sulphur from mineral transformer oils using low temperature reagent based technology and change hazardous practice of oil regeneration with reactivating adsorbents. These technologies blow off toxic emissions (dioxins) if applied on non PCB-free oil and additionally produce elemental sulphur which induce power transformer failure. Most of these technologies can’t remove elemental sulphur once it has contaminated transformer oil. Newly developed technology – GreenCleanS with previously patented technology for the removal of PCB and corrosive disulphides (RS patent 53510) will become integrative solution 3PINT for the removal of elemental sulphur, PCB, disulphides and oil ageing products from mineral transformer oils. Development of new technology for the removal of elemental sulphur from transformer oils will comprise insulating oil treatments in laboratory and on a pilot scale (TRL4), followed by demonstration of developed technology in operational environment in transformer power station in Serbia on batch of 3 tons of oil in INT mobile plant to achieve TRL 7. Previously patented technology (RS 53510) will be included in on-site demonstration in order to demonstrate integrative solution for mineral transformer oil treatment – 3PINT. Project results are going to contribute to green and sustainable power delivery and benefits for the environment and society. Mitigation of power transformers failures and reduction of air pollution, caused by currently applied oil regeneration processes with reactivating adsorbents will be available with development of GreenCleanS and utilization of 3PINT. Reduction of waste oil generation, pollution of the environment and power transformers carbon footprint will bring strong positive impact on citizen’s healthcare, huge savings on the costs of capital equipment, avoiding economic and societal losses of undelivered electricity.
Keywords: innovative technology, transformer oil treatment, environmentally closed technology , corrosive sulphur, elemental sulphur
ABSTRACT: 3PINT and related innovative technologies as permanent solution to mitigate corrosive sulphur in power transformers
Focus of 3PINT project is to upgrade readiness level of the innovative technology for the removal of corrosive sulphur, PCB and aging product from transformer oils. Technology itself includes chemical conversion process to refine transformer oils in eco-frendly manner. Used technology is environmentally closed with no toxic emissions and waste released into environment. In addition, innovative solution for corroded silver-plated contacts cleaning, effectively removes silver sulphide deposits from OLTC contacts, ensuring long-term reliability and complete power transformer corrosive sulphur mitigation.
Keywords: 3PINT, innovative technology, environmentally closed technology, power transformer, complete corrosive sulphur mitigation
Abstract: Aging Tests of Alternative Insulating Liquids
Using alternative insulation liquids as a replacement of mineral oil took place since decades. Until now there is no regulation in the standards to identify the degradation of solid or liquid insulation under the application of alternative liquids. Most of investigations rely on the guidance known and used for mineral oil, which leads mostly to confusion and are misleading. Determination of aging and end of life for transformers filled with mineral oil is based on huge amount of information and experience gathered since oil transformers were built. The limits of key properties and DGA analysis are well defined for reconditioning, reclaiming and replacement of mineral oil as well as for fault detection in transformers. Efforts of research community were focused to extract these rules and modify them to fit to alternative liquids, however, until now there is no real success in this area. In this study, comparative laboratory aging tests of two natural esters of the same base were performed. Tests were conducted at 180 °C in stainless steel vessels with two different types of paper and four different metallic components in defined ratios corresponding to real power transformers. After several aging periods up to 28 days was finished, the key properties of insulating liquids were measured, such as: gasses dissolved in the oil, acidity, breakdown voltage, water content, interfacial tension, viscosity, antioxidant content, as well as degree of polymerization of the paper and water content in the paper. The aging results provided valuable insights into the differences in aging and gas emission patterns of the tested liquids, which varied depending on the type of paper used and the antioxidants present in the liquids. Additionally, the study demonstrated the interrelationship of liquid properties at various stages of paper degradation. The findings highlighted the importance of performing compatibility tests between insulating liquids and other materials intended for use before their application in power transformers.
Keywords: Aging Test, Compatibility, Lifetime, Natural Ester, Power Transformer
Biography of the presenter
Jelena’s field of expertise is insulating oil and paper analyses and power transformers condition assessment, insulating oil and cellulose ageing, know-how in oil treatment processes for the removal of corrosive sulfur and PCB. She holds two registered patents in this field. She has published 92 research and technical papers and has been a project leader of more than 20 research projects. Jelena has been a member in more than 20 CIGRE SC D1, SC A2 and IEC TC 10 WG’s over the past two decades. She is currently convener of CIGRE WG D1.76: Tests for the verification of quality and ageing performance of cellulose insulation for power transformers and CIGRE SC a2.02. Task Force on Silver Corrosion in Power Transformers (2024-2025). Jelena Lukic is a delegate of the Serbian National Committee in International Electro-technical Committee Technical Committee 10 (IEC TC 10) – Fluids for Electro-technical Applications, Distinguished member of CIGRE in 2024 and IEC TC 10 Liaison Co-officer of CIGRE SC A2.
