In the power distribution system, the selection of transformers directly affects the safety of power supply and the cost of the project. Dry type and oil-immersed type are currently the two mainstream solutions. How to choose? This article combs the key differences from the perspective of actual combat.
I. Core Differences at a Glance
| Comparison Dimension | Dry-type Transformer | Oil-immersed Transformer |
| Insulation Medium | Epoxy resin + air | Transformer oil (mineral oil/natural ester) |
| Fire Performance | Flame-retardant, self-extinguishing, no toxic smoke | Combustible, requires separate transformer room and fire protection |
| Installation Location | Can be placed at load center, adjacent installation | Requires outdoor or separate indoor room, away from people |
| Environmental Friendliness | No oil leakage risk, zero pollution | Potential leakage risk, waste oil requires hazardous waste disposal |
| Maintenance Cost | Essentially maintenance-free, only requires dust cleaning | Requires regular oil level, oil quality, and seal inspection |
| Overload Capacity | Relatively weak, relies on ventilation for heat dissipation | Strong, oil medium has high heat dissipation efficiency, suitable for heavy loads |
| Initial Cost | Higher | Lower |
| Lifecycle Cost | Significant long-term cost advantage | Requires consideration of maintenance and environmental disposal costs |
II. Quick Selection Guide
Priority is given to dry transformers
Densely populated places: high-rise buildings, shopping malls, hospitals, schools, subways
Space-restricted areas: basement, underground garage, wind power tower
Environmentally sensitive projects: residential areas, commercial
complexes, scenic spots
Priority is given to oil-immersed transformers
Outdoor installation: box transformer, pole installation, open-air substation
Industrial large capacity: factories, mines, power stations, photovoltaic booster stations
Cost-sensitive projects: limited budget and independent power distribution room
III. One-Sentence Selection Logic
- For safety, flexibility, and maintenance-free operation → Choose Dry-type Transformer (especially preferred for indoor projects)
- For high capacity, low cost, and outdoor use → Choose Oil-immersed Transformer (ensure proper fire protection planning)
