Three Phase Transformers

Three-phase units from 50 kVA upward. Dyn11 or Yyn0, copper or aluminium, oil immersed or cast resin. This is the core of what we build.

Technical specification

Power Rating	50 – 16000 kVA depending on type
Primary Voltage	3.3 / 6 / 10 / 11 / 13.2 / 13.8 / 15 / 20 / 22 / 33 / 34.5 / 35 kV class
Secondary Voltage	480/277 V, 400/230 V, 380/220 V, or customized
Phase	Three-phase
Cooling Type	ONAN
Core Material	High-efficiency (CRGO) silicon steel
Connection Group	Dyn11, Yyn0, Dyn5
Winding Material	Copper / Aluminium
Frequency	50 / 60 Hz
Insulation	Mineral oil
Tap Changer	± 2 × 2.5% Off-Circuit Tap Changer (OCTC)
Short-circuit impedance	4 – 6%
Temperature Rise	60 – 65 °C
Noise Level	≤ 60 dB at 1 meter
Enclosure	Hermetically sealed steel tank, weatherproof for indoor and outdoor use
Altitude	≤ 1,000 m or customized
Ambient Temperature Range	-30 °C to +50 °C
Accessories	Conservator tank, oil level indicator, gas relay, pressure relief valve, etc.
Standards Compliance	IEC 60076, IEEE C57, ANSI C57
Applications	Commercial and institutional buildings, industrial facilities, oil & gas, solar and wind energy, utility grid connections, data centers, and coastal islands and high-altitude regions.
Transport & Installation	Lifting lugs, skid base, galvanized fittings
Warranty	Two years
Delivery Time	Typically 30 days, depending on quantity
Min. order quantity	≥ 1 set

100 · 200 · 315 · 500 · 630 · 800 · 1000 · 1250 · 1600 · 2000 · 2500 · 3150 kVA

Other ratings are built to order. If your rating is not on this list, send it anyway.

Core: cold-rolled grain-oriented silicon steel, mitred step-lap, clamped to hold noise down.
Winding: copper or aluminium, wound in-house.
Tank: corrugated wall or radiator, pressure tested before filling.
Drying: vacuum drying in our own plant, then vacuum oil filling.
Sealing: hermetically sealed, or conservator with a silica-gel breather.

Off-circuit ±2 × 2.5%, or an on-load tap changer.

Copper or aluminium, to the loss figures you need to meet.

Pressure relief device, gas relay, oil level and temperature indicators.

HV cable box or bushings, LV busbar or cable box.

Winding temperature indicator with alarm and trip contacts.

Standard industrial paint, or the colour your utility specifies.

Routine tests on every unit: winding resistance, ratio and vector group, insulation resistance, impedance voltage, separate-source and induced voltage withstand.
Type tests on request: temperature rise, lightning impulse, short-circuit withstand.
Designed and tested to IEC 60076. IEEE and ANSI practice applied for 60 Hz designs.
A test report in English goes out with every transformer.

What is the lead time?

Typically 30 days after drawing approval, depending on the quantity and the rating.

One set. We build to order, so a single transformer is a normal order for us.

Can you build to our drawing?

Yes. Send the specification, a data sheet or a photo of the old nameplate and we will quote against it.

How is the transformer packed?

Seaworthy export packing with desiccant and a moisture indicator; the exact case type is confirmed with the order.

What warranty do you give?

Two years from commissioning.

Every model below is built to order in the same Baoding factory. Open a sub-category to see models, ratings and specification tables.

Rating, primary and secondary voltage, frequency, quantity and the application. We answer within one working day.