Transformer

A: Oil-Immersed Transformers rely on mineral or synthetic oil for cooling and electrical insulation. They offer lower initial purchase costs, higher overload capacity, and superior heat dissipation, making them the standard choice for outdoor distribution and power utility installations.

Cast Resin Dry-Type Transformers use solid epoxy resin encapsulation for their windings. They contain no liquid dielectrics, eliminating fire hazards and liquid leakage risks. Dry-type units are required for indoor applications, high-rise buildings, underground facilities, and environmentally sensitive sites where fire safety codes prohibit oil-filled equipment.

A: We build transformer cores using high-grade, cold-rolled grain-oriented (CRGO) silicon steel processed on automated step-lap shearing lines, which minimizes no-load losses (P0). Winding cross-sections are engineered using high-conductivity copper to maintain load losses (Pk) within tolerances. Every transformer undergoes no-load and load-loss testing in our high-voltage laboratory, and certified values are recorded on the FAT report provided prior to shipment.

A: Yes. For oil-immersed transformers installed in coastal or marine environments (C4 or C5-M anti-corrosion classes), we supply stainless steel hardware, polymeric high-voltage bushings, and a multi-stage epoxy / polyurethane surface coating system tested to withstand 1,000+ hours of salt spray exposure according to ISO 12944. Dry-type units receive protective anti-fungal and anti-saline varnish coatings over exposed core laminations and busbars.

A: We produce all standard IEC and IEEE vector groups. The most common distribution configuration is Dyn11 (Delta primary, Star secondary with neutral), which isolates triple harmonics and allows single-phase lighting / power loads. Other vector groups, such as Ynd11, Dyn5, Yyn0, or dual-secondary Dy11y11 configurations for solar inverters, are available upon engineering review.

A: Every manufactured transformer undergoes 100% factory routine testing per IEC 60076. This includes winding resistance measurements, voltage ratio and vector group checks, short-circuit impedance and load loss tests, no-load loss and current measurements, separate-source AC voltage withstand tests, and induced overvoltage withstand tests. Cast resin units additionally undergo partial discharge testing to ensure values remain below 10 pC.

A: Standard distribution units (50 kVA to 2,500 kVA) with standard voltage ratios have a manufacturing lead time of 3 to 4 weeks. Custom-engineered power units, specialized step-up transformers, or units requiring non-standard enclosure ratings (IP54 / IP55) or On-Load Tap Changers (OLTC) typically ship within 5 to 7 weeks following formal technical drawing approval.