Transformer Conservator Tank
A conservator tank is an essential componont of oil-filled power and distribution transformen. It plays a crucial role in maintaining the proper level and quality of insulating oil inside the main tank of the oil explonds and Contracts with temperature variations during transformer operation
Purpose and Function
- Accommodate oil expansion and contraction due to temperature changes in the transformer
- Prevent oil leakage and maintain proper oil level in the main tank.
- Reduce contact between oil and atmosphere (through a breather system), thereby mimimizing oxidation and moisture contamination.
Working Principle
When the transformer is emergized:
- The temperature of the oil increases, causing it to expand and move into the conservator tank.
- When the load decreases or ambient temperature drops, the oil contracts and returns from the conservator tank to the main tank.
- The conservator tank acts as a reservoir, ensuring a constant oil level and pressure balance.
Construction Details
A typical conservator tank consists of:
- Oil level indicator (oilgouge) to monitor oil level.
- Breather connection filled with a silica gel breather to absorb moisture from air entering the tank.
- Drain valve and filling pipe for maintenance.
- Separator diaphragm or bladder (optional) to prevent direct contact of oil with air.
Types of conservator Tanks
- Plain conservator Tank
- No separation between oil and air.
- Economical but more prone to oil oxidation and moisture contamination.
- Conservator with Rubber Diaphragm or Bladder
- Equipped with an oil-air separator prevents direct contact of oil with atmosphere.
- Enhances oil life and reduces maintenance.
Advatanges
- Maintains consistent oil level & pressure.
- Prevents excessive stress on transformers seals and joints.
- Reduces oil contamination and aging.
- Improve reliability and life of transformer.
Accessories
Common accessories mounted on or connected to the conservator tank include:
- Magnetic oil level gauge (MOG)
- Dehydrating silica gel breather.
- Buchholz relay (for fault detection, between conservator and main tank).
- Drain and filling plugs.
- Air release valve.
Material and Finish
- Generally made of mild steel with anti-corrosive paint or powder coating.
- Hot-dip galvanized (HDG) finish available for improved corrosion resistance, especially for outdoor or coastal applications.