Dry Type Transformer (CAST Resin Transformer)
Dry type transformers don’t use any liquids for insulation. Regular transformers operate with an insulating liquid where the core is immersed in it. The dry type transformers use a different technique and use a pressurized container surrounded by air. The core is kept inside the pressurized container.
- These are the main benefits of using a cast resin dry type transformer:
- Easy installation technique
- Quick maintenance and pollution-free design
- Low side clearance
- Supports overloads excellently
- Affordable for fire protection and civil installation systems
- Resistant to short circuits, low dielectric heating
- Works well in moisture
- These transformers are primarily found in: Forests
- Substations in the city
- Gas, oil, and chemical industries
- Environmentally challenged areas
- Underground substations
- Renewable energy generation lands.
Design factors for cast resin dry type transformers :
- Insulation type – F and H types of insulation are primarily used for the primary and secondary winding due to temperature management, thermal shock resistance, and dielectric strength.
- Winding Material – Windings made with copper or aluminum varied with the current rating requirement.
- Core material and Hysteresis Loss – silicon steel is generally used to supply high permeability and minimum hysteresis. Regulation – is achieved with a leak resistance of <2% in the design.
- Life – depends on the winding insulation breakdown with the effect of temperature rise due to overload.
- Losses – for the eddy current and core loss to be independent, leakage and winding resistance should stay within moderation with voltage regulation to ensure high efficiency.
- Overload – it results in overheating, which limits the loading demand. A fan-cooling system is added to the dry-type transformer to avoid this problem.
- The insulation level is chosen according to the primary impulse level, and the system adds to the transformer’s life.
- K-factor – withstands the non-sinusoidal heat generation in the winding. Harmonics in the transformers are added to alter this issue.