Conservator Tank Design vs. Sealed Design: Choosing the Right Substation Transformer for Your Needs

Transformer with wires and electrical equipment displayed.

Conservator Tank Design vs. Sealed Design: Choosing the Right Substation Transformer for Your Needs

Substation transformers are crucial components of electrical distribution systems, responsible for stepping up or stepping down voltage levels to ensure efficient power transmission. When selecting a substation transformer, one of the critical decisions is choosing between conservator tank design and sealed design. Each design comes with its advantages and disadvantages, and understanding the differences can help you make an informed decision for your specific requirements.

Conservator Tank Design

Conservator tank design is one of the traditional and widely used approaches for substation transformers. In this design, the transformer is equipped with an external tank known as the conservator tank. Here’s a closer look at the key features and benefits of conservator tank design:

Substation Transformers: Conservator Tank Design

1. Oil Expansion: The conservator tank contains transformer oil, which expands and contracts with temperature changes. This allows for the accommodation of temperature-related variations in the oil volume, reducing the risk of internal pressure build-up.

2. Breather: The conservator tank also includes a breather that filters and dehumidifies the air entering the tank. This ensures the transformer oil remains free from moisture and contaminants, prolonging the transformer’s lifespan.

3. Visual Oil Level Indicator: One of the advantages of the conservator tank design is its visual oil level indicator, allowing operators to monitor the oil level easily. This helps detect potential issues and schedule maintenance as needed.

4. Access to Components: Conservator tank transformers provide relatively easy access to some internal components, such as the tap changer and bushings. This access can be beneficial for certain maintenance tasks.

Sealed Design

Substation Transformers: Sealed Design

Sealed transformers, as the name suggests, are sealed units that do not have a conservator tank. Instead, they are designed to be completely sealed from the environment. Let’s delve into the characteristics and advantages of sealed transformer design:

1. Environmentally Friendly: Sealed transformers are often considered more environmentally friendly because they prevent oil leakage and minimize the risk of oil pollution, making them suitable for installations in environmentally sensitive areas.

2. Reduced Maintenance: Sealed transformers generally require less maintenance due to the absence of a conservator tank and associated components. This can result in lower long-term operational costs.

3. Compact Design: Sealed transformers are typically more compact than conservator tank transformers, making them a space-saving option for substations with limited space availability.

4. Enhanced Fire Safety: Sealed transformers are less prone to oil-related fires since there is no external oil containment system. This can be a critical factor in areas where fire safety is a concern.

5. Longer Service Life: The absence of air-breathing components means that sealed transformers may have a longer service life, as they are less exposed to contaminants and moisture.

Choosing the Right Design

The choice between conservator tank design and sealed design for your substation transformer ultimately depends on your specific needs and project requirements. Here are some factors to consider when making this decision:

Environmental Considerations: If your substation is in an environmentally sensitive area, a sealed transformer may be the more appropriate choice to prevent oil leakage.

Space Constraints: Consider the available space in your substation. If space is limited, a sealed transformer’s compact design may be advantageous.

Maintenance Requirements: Assess your team’s maintenance capabilities and resources. If you require a transformer with lower maintenance demands, a sealed design might be preferable.


The choice between a conservator tank design and a sealed design for your substation transformer is a crucial decision that depends on many factors, including environmental considerations, maintenance requirements, and budget constraints.

Understanding the differences between these two designs is a good start to making an informed decision for your project’s specific needs and goals. Ultimately, both designs have their advantages, and selecting the right one can add to the efficiency and reliability of your electrical distribution system.

As we mentioned earlier reconditioned substations can offer a lot of savings, what’s the catch? Well actually there may not be a catch, if your project allows for reconditioned transformers, you will see many benefits.

All our reconditioned substations come with a three-year warranty because we back the reliability of our units. Even with this long warranty the price is usually lower than new units with shorter warranties.

If you are in the market for a substation or any type of transformer, feel free to reach out to our sales team. Either by sending us an email at [email protected] or call in at 855-214-0975.