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Why do transformers need breathers ?

Transformers require breathers for effective and reliable operation. A breather is a device installed on transformers to control the air entering and leaving the transformer’s main tank, ensuring that the internal atmosphere remains dry. Let’s delve into the reasons why transformers need breathers:

1. Moisture Control:

  • Hygroscopic Nature of Oil:
    • Transformers are filled with insulating oil, which is hygroscopic, meaning it has a tendency to absorb moisture from the surrounding air.
  • Moisture in Oil:
    • If moisture accumulates in the transformer oil, it can lead to a reduction in the insulating properties of the oil, potentially causing electrical breakdowns and deterioration of the transformer’s insulation system.
  • Breather Desiccant:
    • A breather typically contains a desiccant (moisture-absorbing material) to prevent moisture from entering the transformer. As air passes through the breather, the desiccant absorbs moisture, helping to maintain the dryness of the internal atmosphere.

2. Preventing Contamination:

  • Dust and Particles:
    • Transformers are susceptible to the ingress of dust, dirt, and other particles from the environment.
  • Breather Filtration:
    • The breather is equipped with a filtration system to prevent the entry of contaminants into the transformer. This helps maintain the cleanliness of the insulating oil and reduces the risk of insulation breakdown.

3. Thermal Expansion and Contraction:

  • Temperature Changes:
    • Transformers experience temperature variations during operation, leading to thermal expansion and contraction of the insulating oil.
  • Air Volume Changes:
    • As the oil expands, it displaces air from the transformer tank. Conversely, during contraction, a vacuum can be created.
  • Breather Compensates:
    • The breather compensates for these volume changes by allowing air to enter or exit the transformer tank in response to temperature fluctuations. This prevents the development of a vacuum or excessive pressure inside the transformer.

4. Pressure Relief:

  • Pressure Buildup:
    • In some situations, such as during sudden temperature increases, the internal pressure in the transformer may rise.
  • Pressure-Relief Valve:
    • Transformers may be equipped with a pressure-relief valve to release excess pressure. The breather assists by allowing air to enter or exit, contributing to pressure regulation and preventing damage to the transformer.

5. Visual Indication of Desiccant Condition:

  • Color Change:
    • Some breathers are designed with a visual indication feature. The desiccant material changes color as it absorbs moisture, providing a visible signal that the breather needs replacement or regeneration.

6. Maintenance and Monitoring:

  • Regular Inspection:
    • Breathers facilitate easy monitoring of the transformer’s internal condition. Maintenance personnel can visually inspect the breather and desiccant to assess whether replacement or regeneration is necessary.
  • Preventive Maintenance:
    • Regular inspection and replacement of breathers are part of preventive maintenance practices to ensure the long-term reliability and performance of transformers.

7. Specialized Applications:

  • Critical Environments:
    • In critical environments where maintaining optimal insulation properties is crucial, breathers with advanced features, such as self-regenerating desiccants, may be employed.

8. Conclusion:

  • Integral to Transformer Health:
    • Breathes play a vital role in maintaining the health of transformers by controlling moisture, preventing contamination, compensating for thermal expansion, and regulating internal pressure. They contribute to the reliability and longevity of transformers in various applications.

In summary, transformers need breathers to control moisture, prevent contamination, compensate for thermal expansion, regulate pressure, and facilitate easy maintenance. Breathes are integral to ensuring the optimal performance and reliability of transformers in diverse operational conditions.

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