Core
The core is made of high-permeability cold-rolled grain-oriented silicon steel and features a step-lap lamination structure. The cross-section of the core limb is a multi-step circular shape, uniform with the cross-section of the yoke.
Winding
The windings adopt corrugated oil ducts utilizing a non-impregnation process and are bound with shrinkable tape; all windings are concentric coils. Taps of the high-voltage winding shall have corresponding tap voltages and be led out to a tap changer, which shall be mounted on the tank cover. When changing the tapping voltage, the power supply must be disconnected first.
Installation of Protective Devices
All transformer capacities are equipped with a pressure relief valve.
A gas relay with alarm and trip terminals can be provided upon request.
Oil Temperature Indication Deviation
All transformers are equipped with a pocket for a glass-stem thermometer, which is mounted on the tank top and immersed in the oil approximately 120 ± 10 mm.
Transformers rated 1000 ~ 2000 kVA are equipped with an outdoor signal thermometer.
Transformer Tank
The transformer tank features a corrugated wall, with a powder-coated surface that is reinforced with film. The corrugated radiators not only serve a cooling function but also act as a "breathing" mechanism; their elasticity allows them to accommodate oil volume changes caused by temperature variations. Consequently, this eliminates the need for a hermetically sealed protection, which also reduces the overall height of the transformer.
The transformer adopts vacuum oil filling technology during the sealing process to completely remove moisture from the transformer and prevent contact between the transformer oil and air. This technique also avoids deterioration of insulating properties or oil aging caused by the ingress of oxygen or moisture, thereby enhancing the operational reliability of the transformer.
Main Technical Parameters
Service Conditions
Installation Altitude: The altitude must not exceed 1000 m.
Ambient Temperature: -40 ℃ ~ 40 ℃.
Dimension Selection
Ordering Guide
Please specify in the order the product model, rated capacity, HV/LV rated voltage and high-voltage tapping range, number of phases, frequency, connection symbol, etc.
Packaging and Transportation
Packaging Details: Standard export packing
Port of Delivery: Shanghai or Ningbo
Frequently asked questions
1. What is the difference between the S9, S11, S13 and S22 series?
They differ mainly in core material and loss level. Lower series numbers are older designs with higher no-load loss; higher series use improved core steel and reduce no-load loss step by step. Selection is normally driven by the loss limit your utility or your own cost-of-loss calculation requires, not by price alone.
2. Sealed tank or conservator — which should I specify?
Sealed corrugated tanks remove the oil conservator and the silica breather, which reduces maintenance and moisture ingress — well suited to humid and coastal sites. Conservator designs remain preferable where large oil volume, easier sampling or higher ratings make pressure sealing impractical.
3. Which voltage class and tapping range can you supply?
Units are built to the system voltage you declare, with off-circuit tapping ranges quoted per project. Tapping range must cover the actual voltage variation at your installation point, so we ask for nominal and maximum system voltage plus the expected variation before quoting.
4. What vector group do you normally provide?
Dyn11 is the most common for distribution duty with a neutral. YNd11, Yyn0 and other groups are available where the neutral earthing practice or the harmonic behaviour of your network requires them. The vector group is confirmed in the technical agreement, not assumed.
5. Which standards and tests apply?
Design and testing follow IEC 60076 (and the equivalent national standard where required). Routine tests are performed on every unit; type-test reports are provided for the design family. If your project requires a specific third-party witnessed test, state it in the enquiry.
6. Can the transformer be built for high ambient temperature or altitude?
Yes, but it must be declared in the enquiry. Above the standard ambient reference or above 1,000 m, the unit is dimensioned differently for the same kVA. Specifying a standard unit for a 45 °C site is a common and expensive mistake.
7. Do you supply accessories and documents?
Typical scope includes bushings, lifting lugs, rating plate, earthing terminals and the routine test report with serial number traceability. Breather, silica, Buchholz relay, temperature indicator and OLTC are quoted according to configuration. The document package can be issued in English, Spanish, Portuguese or Chinese.
8. How is shipping protection handled?
Either oil-filled or nitrogen-filled transport is available, with pressure monitoring and shock recording where required. The choice depends on rating, transit time and the receiving site's capability — it is fixed at order, not at dispatch.
