Drop of knowledge #21
Welcome to the twenty-first edition of the Ecol Laboratory newsletter.
1. How does moisture affect the service life of transformers?
The water content in electrical insulating oil and the directly related moisture content of the transformer’s paper insulation have a direct impact on its insulating and dielectric properties, as well as the transformer’s service life.
The dielectric strength of the oil, reflected by its breakdown voltage, depends primarily on the type of insulating liquid (mineral oil, ester oil), the dissolved water content (the degree of oil saturation with water), the solid particle content, the dissolved gas content, and the temperature of the tested sample.
The service life of a transformer depends on the condition of the paper insulation, which serves as a structural support element for the windings. Loss of mechanical insulation strength due to paper disintegration leads to failure and serious damage to the windings.
The decomposition of the cellulose fibers from which the paper is composed occurs under the influence of temperature and moisture (hydrolysis) and is catalyzed by acidic oil oxidation products. The graph below shows the relationship between the theoretical transformer service life and the transformer’s service life:
The moisture content of the paper (cellulose) directly affects the water content dissolved in the oil. The following graphs show the solubility of water in oils: on the left, ester oils, and on the right, mineral oils:
The process of water dissolving in oil depends on the base oil used (mineral, ester), paper moisture content, and temperature. This allows for the estimation of insulation moisture content based on the collected oil samples. This requires knowledge of the transformer temperature at the time of sampling.
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3. Upcoming conferences we are participating in:
- ➡️ 1-3.10.2025 r., BMP Symposium AGGREGATES CEMENT LIME, Kielce, Poland
- ➡️ 1-2.10.2025 r., Plastinvent Conference, Wisła, Poland
- ➡️ 1-2.10.2025 r., PRECOP Conference, Katowice, Poland
- ➡️ 7.10.2025 r., Axon – Reliability and Maintenance in Manufacturing Plants, Rzeszów, Poland
- ➡️ 7-9.10.2025 r., BALTEXPO 23rd International Maritime and Military Fair, Gdańsk, Poland
- ➡️ 8-10.10.2025 r., PRO NOVUM Symposium Diagnostics and servicing of equipment in nuclear and conventional power engineering, Bystra, Poland
- ➡️ 9-10.10.2025 r., Wind power plants – safety and operation, Kołobrzeg, Poland
- ➡️ 14-16.10.2025 r., Warehouse Process Improvement Conference, Poznań, Poland
- ➡️ 16-17.10.2025 r., METALKO – Ammonia workshops, Poznań, Poland
- ➡️ 20-22.10.2025 r., INIG Conference LUBRICANTS, Zakopane, Poland
- ➡️ 21-22.10.2025 r., MEGAWATT Conferece, Bergamo, Italy
- ➡️ 28-29.10.2025 r., Modern Tram Technologies Conference, Bydgoszcz, Poland
- ➡️ 28-30.10.2025 r., vgbe Chemistry Conference 2025, Kassel, Germany
4. Gas of the month
Propane (C3H8) – a saturated hydrocarbon, colourless and odourless gas. It occurs in natural gas and crude oil. Insoluble in water, highly soluble in alcohol, ether and oils. Used as a fuel, in organic synthesis and as a refrigerant.
Propane has become a popular choice for barbecues and portable stoves because its low boiling point, -42°C, causes it to vaporise inside pressurised containers (it exists in two phases – vapour above liquid).
👉 It retains its evaporation capacity even in cold weather, making it better suited for outdoor use in cold climates than its butane blend.
🔬In the diagnostics of oil transformers, propane is one of the dissolved gases analysed (DGA method). Its formation in transformers is mainly associated with low-temperature overheating, similar to its lighter diagnostic counterpart, ethane.
❗ Propane, as a gas that is highly soluble in oil, accumulates and indicates overheating occurring over a longer period of time. A comparison of propane and ethane concentrations makes it possible to determine the activity of thermal defects over time.
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