Power Transformers

Energy-Saving 25 / 30 MVA Oil-Immersed Power Transformer 66–110 kV

An energy-saving three-phase oil-immersed power transformer rated 25 and 30 MVA, stepping 66 / 110 kV down to 23 kV for substation and distribution networks.

An energy-saving three-phase oil-immersed power transformer rated 25 and 30 MVA, stepping 66 / 110 kV down to 23 kV for substation and distribution networks. Its low-loss core and windings reduce no-load and load losses, cutting operating cost over a 20-year design life. Sealed steel tank with radiator cooling and conservator; copper or aluminium windings, IEC/GB compliant.

  • Energy-saving low-loss design — reduced no-load and load losses
  • 25 / 30 MVA at 66–110 kV for substations and distribution
  • Oil-immersed sealed construction with radiator cooling and conservator
  • Vector group Dyn11 / Yyn0 to suit single-line requirements
  • Certified UL, IEC, CE, ISO9001/14001/45001, CQC, GOST, EAC
Product TypeThree-Phase Oil-Immersed Power Transformer
Rated Capacity25 / 30 MVA
Input Voltage (HV)66 / 110 kV
Output Voltage (LV)23 kV
Frequency50 / 60 Hz
PhaseThree
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Lead time typically 25–45 days after drawing approval · FAT welcome · Ships worldwide (EXW / FOB / CIF / DAP)

Technical specifications

Specifications of Energy-Saving 25 / 30 MVA Oil-Immersed Power Transformer 66–110 kV
ParameterValue
Product TypeThree-Phase Oil-Immersed Power Transformer
Rated Capacity25 / 30 MVA
Input Voltage (HV)66 / 110 kV
Output Voltage (LV)23 kV
Frequency50 / 60 Hz
PhaseThree
Winding MaterialCopper / Aluminium
Vector GroupDyn11 / Yyn0
CoolingONAN / ONAF (oil-immersed, radiator)
StandardIEC / GB
CertificationUL, IEC, CE, ISO9001, ISO14001, ISO45001, CQC, GOST, EAC
Service Life20 Years
PackingWooden Case
Energy-Saving 25 / 30 MVA Oil-Immersed Power Transformer 66–110 kV — specification and nameplate detail
Specification and nameplate detail

Specifications are based on the standard configuration. Final ratings, dimensions, materials and packaging are confirmed on the approved drawing and order confirmation.

Features and construction

The sealed steel tank carries high-voltage porcelain bushings, a top-mounted conservator for oil expansion, side radiator banks for cooling and a control cabinet for monitoring and protection. Energy-saving low-loss materials cut lifetime operating cost, while the oil-immersed construction ensures efficient cooling and stable insulation for reliable substation service.

Energy-Saving 25 / 30 MVA Oil-Immersed Power Transformer 66–110 kV — construction and materials detail
Construction and materials detail
Energy-Saving 25 / 30 MVA Oil-Immersed Power Transformer 66–110 kV — internal structure
Internal structure
Energy-Saving 25 / 30 MVA Oil-Immersed Power Transformer 66–110 kV — workmanship detail
Workmanship detail
Energy-Saving 25 / 30 MVA Oil-Immersed Power Transformer 66–110 kV — safety and protection features
Safety and protection features

Typical applications

Utility and industrial substations, power transmission and distribution networks, renewable-energy stations and large plants requiring efficient 66–110-kV-class transformation.

Energy-Saving 25 / 30 MVA Oil-Immersed Power Transformer 66–110 kV — typical application
Typical application

Customisation options

Capacity, HV/LV voltage, vector group, tap-changer type, cooling class and fittings are customizable to project single-line requirements.

Energy-Saving 25 / 30 MVA Oil-Immersed Power Transformer 66–110 kV — dimensions and layout
Dimensions and layout
Energy-Saving 25 / 30 MVA Oil-Immersed Power Transformer 66–110 kV — customisation options
Customisation options

Ordering information

  • Selling Unit: Single item
  • Packing: Wooden Case
  • Standards: IEC / GB; certified UL, IEC, CE, ISO9001/14001/45001, CQC, GOST, EAC

Specifications are based on the supplied product data. Final dimensions, materials, colors, and packaging are subject to the confirmed sample and order confirmation.

Standards and quality

Manufactured under an ISO 9001, ISO 14001 and ISO 45001 certified management system. Designs follow the IEC 60076 / IEC 62271 series as applicable, with ANSI/IEEE, GB and GOST variants available. Every unit passes routine testing before dispatch; type tests and customer or third-party witnessed factory acceptance tests can be arranged.

Frequently asked questions

What is the rated capacity of the Energy-Saving 25 / 30 MVA Oil-Immersed Power Transformer 66–110 kV?

The standard configuration is rated 25 / 30 MVA at 50 / 60 Hz. Other ratings in the same family can be built to order — tell us the load and we will confirm the nearest standard rating.

What voltage ratio is available?

The standard unit is 66 / 110 kV input to 23 kV output. Voltage ratio, tapping range and vector group can be adjusted to your network; 50 Hz and 60 Hz designs are available.

Which standards and certifications apply?

The product is designed to IEC / GB. MARS operates an ISO 9001 / 14001 / 45001 certified factory and holds CE (ECM), UDEM, EAC and CQC approvals; every unit is routine-tested before dispatch and type or witnessed tests can be arranged.

Can this product be customised?

Capacity, HV/LV voltage, vector group, tap-changer type, cooling class and fittings are customizable to project single-line requirements.

What is the lead time and how is it shipped?

Packed in wooden case. Typical lead time is 25–45 days after drawing approval for distribution equipment and 60–90 days for power transformers and containerised systems. Shipment is by sea from Shanghai on EXW, FOB, CIF or DAP terms with a full document pack.

Enquire about this product

Tell us the rating, voltage ratio, frequency, quantity and destination. A MARS engineer replies with a technical proposal and quotation within one working day.

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