Engineering Case
5 Critical Components of Dry-Type Transformers That Ensure Longevity
Release time:
2026-04-23 09:07
In modern power systems, dry-type transformers are widely utilized in data centers, commercial buildings, industrial manufacturing, and renewable energy projects due to their high safety standards, environmental friendliness, and low maintenance costs. Its core structure primarily consists of four major parts: the magnetic circuit system, the electrical circuit system, the insulation and support system, and the protective enclosure.
1. Iron Core (Magnetic Circuit System)
The iron core serves as the path for magnetic flux.
- Material: It is typically made of high-permeability, low-loss, high-quality cold-rolled grain-oriented (CRGO) silicon steel sheets.
- Structural Craftsmanship:
- To minimize noise and no-load losses, the laminations usually employ a full-mired joint （45°stacking） process.
- The surface is coated with anti-rust resin to prevent moisture and corrosion.
- Tie Plates and Clamps: The core is tightened using high-strength channel steel clamps and tie plates to ensure mechanical strength and reduce vibration noise.
2. Windings (Electrical Circuit System)
The windings are the electrical heart of the transformer, categorized into high-voltage (HV) and low-voltage (LV) windings.
- High-Voltage Winding: Most utilize an epoxy resin cast structure. The thin insulation and the coil are cast as a whole under vacuum conditions.
- The structure is typically multi-layer cylindrical or sectional, providing excellent short-circuit resistance and lightning impulse performance.
- Insulation materials generally use Class F or Class H composites (e.g., Nomex paper).
- Low-Voltage Winding: For high-current windings, copper foil winding (foil type) is often used instead of traditional wires. This effectively resolves spiral angle issues under high current and enhances longitudinal mechanical strength.
3. Insulation and Support System
Since there is no transformer oil, the heat dissipation and insulation of dry-type transformers rely entirely on air and solid insulation materials.
- Insulation Class: Commonly Class F (up to 155°C) or Class H (up to 180°C).
- Spacers and Supports: Windings are fixed between the core and each other using elastic spacers and support strips. These components must possess excellent flame-retardant and hydrophobic properties.
- Air Ducts: Longitudinal ventilation ducts are reserved between the HV and LV windings and inside the windings to carry away heat through air convection.
4. Auxiliary Systems (Temperature Control and Cooling)
- Temperature Control System: Pt100 thermal resistance sensors are embedded in the LV windings. The temperature control unit monitors coil temperature in real-time to facilitate automatic fan start/stop, over-temperature alarms, and limit tripping.
- Cooling Fans: Usually installed at the bottom of the transformer. In forced air cooling (AF) mode, the output capacity of the transformer can be increased by approximately 40% to 50%.
- Enclosure (Protection): Common ratings include IP20 (protection against solid foreign objects) or IP23 (protection against spraying water). Materials include aluminum alloy, stainless steel, or powder-coated cold-rolled steel.
Core Components Overview
Component Name | Main Materials | Core Function |
|---|---|---|
Iron Core | Silicon Steel Sheets | Magnetic energy conversion, structural framework |
HV Coil | Copper/Aluminum Wire + Epoxy Resin | Power input/output (High-voltage side) |
LV Coil | Copper/Aluminum Foil + Insulation Paper | Power input/output (Low-voltage side) |
Temp Controller | Microcomputer Control Unit | Temperature monitoring, overload protection |
Cooling Fan | Cross-flow Cooling Fan | Improves heat dissipation and overload capacity |
Insulator | Epoxy Resin or Ceramics | Supports busbars and ensures ground insulation |
Summary of Structural Features
- Safety: Flame-retardant and self-extinguishing; it will not explode or release toxic gases even under extreme conditions.
- Compactness: The compact structure allows it to be placed deep within load centers (such as basements or specific building floors), reducing low-voltage line losses.
- Eco-friendliness: The oil-free design eliminates the risk of leakage, making it suitable for environments with stringent environmental requirements.
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