Transformer Series

The core consideration is fire safety. Dry-Type Transformer: Since it contains no flammable oils, it possesses flame-retardant and self-extinguishing properties. Therefore, it is mandated for use in high-occupancy or sensitive locations such as high-rise buildings, basements, shopping malls, and hospitals. Oil-Immersed Transformer: These units pose risks of fire and leakage. They are typically installed in independent transformer rooms, outdoors, or on poles. If installed indoors, they must be equipped with fire-protection facilities, such as oil containment pits (sumps).

· Efficiency Comparison: Under the same capacity and technical specifications, the no-load losses of oil-immersed transformers are typically slightly lower than those of dry-type transformers. · Grading System: In Chinese standards, a higher number generally indicates better energy efficiency (e.g., S13 is more efficient than S11). The market has now fully transitioned to Energy Efficiency Grades: Grade 1 (NX1): The highest efficiency (lowest power consumption). Grade 2 (NX2): High efficiency. Grade 3 (NX3): The minimum market entry standard.

Dry-type transformers generally exhibit a stronger short-term overload capacity. Dry-Type Transformer: These units are typically equipped with sophisticated temperature control and alarm systems, as well as Forced Air Cooling (AF). When the cooling fans are activated, their short-term overload capacity can reach 20% to 30% or even higher of the rated capacity. Oil-Immersed Transformer: The service life of an oil-immersed unit is highly dependent on the oil temperature and the degradation of the paper insulation. While they can handle overloads, prolonged operation under such conditions accelerates the aging of the insulating oil, significantly shortening the transformer's lifespan.

Dry-type transformers do not require oil changes. However, they must be kept clean and dry. The primary maintenance tasks involve periodic dust removal (to prevent insulation tracking/creepage caused by dust accumulation) and checking for loose fasteners. If the unit has been out of service in a humid environment, an insulation resistance test must be performed before restarting.