Transformer main body construction has several safety protection devices, including:
Oil cushion:
Its capacity is approximately 8-10% of the transformer oil volume. Its main function is to accommodate the volume changes of transformer oil due to temperature variations, limit the contact between transformer oil and air, and reduce oil moisture absorption and oxidation. Moisture absorbers are installed on the oil cushion to prevent air from entering the transformer.
Moisture absorber and oil purifier:
The moisture absorber, also known as a breather, contains adsorbents such as silica gel and activated alumina. Some moisture absorbers contain color-changing silica gel, which turns from blue to red when moisture is absorbed, indicating the need for drying or replacement. The oil purifier, also known as a filter, contains adsorbents such as silica gel and activated alumina in its purifying cylinder. When the oil passes through the oil purifier and comes into contact with the adsorbents, water, acids, and oxides are absorbed, keeping the oil clean and extending its service life.
Explosion-proof tube (safety duct):
Explosion-proof tubes are installed on the transformer tank cover to prevent the release of high pressure inside the tank in case of internal faults. Modern large transformers use pressure relief valves instead of safety ducts. When internal faults occur and pressure rises, the pressure relief valve activates and triggers alarm contacts or circuit breakers.
In addition, transformers have gas protection, temperature gauges, oil level indicators, and other safety devices.