Power Transformer Manufacturer in China: Oil or Dry Type First
The first question a power transformer manufacturer in China will ask you back is not about capacity. It is whether the unit sits indoors or outdoors, and how close people will be standing to it. Answer that and the choice between oil-immersed and cast resin largely makes itself. Capacity, voltage ratio and tap changer come second, and by then the quotation is mostly arithmetic.
What a power transformer manufacturer in China actually needs from you
Four numbers open the conversation: rated capacity in kVA, primary and secondary voltage, vector group, and impedance. Add the installation environment and the local grid frequency and you have enough for a real quote. Everything else, including the cooling method and the enclosure rating, can be worked out from those.
Buyers who send only a kVA figure get a wide price band, and the spread usually reflects what the factory assumed about the rest. A 1000 kVA unit quoted for a basement plant room is a different machine from the same rating on a pole.
Oil-immersed against cast resin
Oil units cool better per kilogram of core and steel, which is why they dominate above a few MVA and at 35 kV and above. The oil carries heat to radiators, and fans or pumps can be added when the load climbs. The trade-off is the oil itself: it needs sampling, it needs a bund or a drain pit, and most fire officers want separation from occupied space.
Cast resin dry types cost more at the same rating and cannot be pushed as hard thermally, but they go inside buildings without a fire room, need no oil handling, and only ask for a dry, ventilated space. That is why high-rise and metro projects specify them almost without discussion.
| Item | Oil-immersed | Cast resin dry type |
|---|---|---|
| Typical range | 100 kVA to several MVA | 30 kVA to 2500 kVA |
| Installation | Outdoor or fire-separated room | Indoor, dry and ventilated |
| Cooling | Oil + radiators, optional fans | Air natural, forced air optional |
| Upkeep | Oil sampling, breather, relay checks | Dust and insulation inspection |
| Unit price | Lower at equal rating | Roughly 20-35% higher |
| Build time | 25-40 days | 20-35 days |
The loss code moves the price more than the rating does
Export units usually come quoted against a loss code, and moving one step up is cheaper than most buyers expect. Going from SCB11 to SCB13 on a 1000 kVA cast resin unit trims no-load loss by roughly 10 to 20 per cent and adds a few per cent to the price. Over a 20-year service life the arithmetic nearly always favours the lower loss, provided the buyer is the one paying the electricity bill.
Ask any power transformer manufacturer in China for the no-load and load loss figures in writing, on the test report rather than in the quotation. Typical no-load loss on a 1000 kVA cast resin unit sits somewhere around 1.5 to 1.9 kW with load loss near 8 to 9.5 kW, but the only numbers that matter are the ones measured on your unit.
Routine tests worth insisting on
IEC 60076 sets out what a factory should perform before every dispatch: winding resistance, voltage ratio and vector group check, no-load and load loss measurement, induced overvoltage withstand, and a separate-source AC test. Temperature rise is a type test rather than a routine one, so it is worth asking when that report was last produced for the design you are buying.
Photographs before shipment cost nothing and catch most of what goes wrong: nameplate against the order, bushing condition, silica gel colour on oil units, and the crate itself. Any power transformer manufacturer in China that expects repeat business will send them without being chased.
FAQ
Q: What is a realistic lead time for a non-standard rating? A: Around 35 to 50 days once the drawing is signed off, because the core and the winding are built to order. Standard ratings can ship faster if the factory has a match on the floor.
Q: Can one container take two units? A: Usually yes up to around 1000 kVA each, but the crate dimensions and the port crane capacity decide it, so confirm the packing drawing before booking.
Where Quanshi fits
Quanshi is a power transformer manufacturer in China building both types in Linyi: oil-immersed units up to and beyond the 500 kVA oil-immersed transformer, and cast resin units such as the 1000 kVA 11 kV dry type transformer for indoor projects. Send the four numbers above to lunaquan1989@163.com or call +86 15588163070, and the reply comes back with a drawing, a loss figure and a build slot rather than a price range. Our earlier note on choosing between dry and oil-immersed designs covers the decision in more detail.