New Siemens Energy 75 MVA 69 kV Three-Phase Substation Power Transformer
CTG Power Systems offers one (1) new Siemens Energy utility-grade three-phase substation power transformer rated 45/60/75 MVA with ONAN / ONAF / ONAF2 cooling. This unit was manufactured by Siemens Energy Transformadores S.A.S. in Colombia, carries Siemens Energy serial number 461316, and is built to IEEE C57.12.00 for substation service.
The transformer is configured 69,000 V high voltage, 34,500 V low voltage, and 13,800 V buried tertiary, with Wye-Grounded / Wye-Grounded / Delta winding arrangement and YNyn0(d1) phase displacement. It features copper windings, a five-position de-energized tap changer on the high side with 2 x ±2.5% tapping range, and fan-assisted cooling for increased capacity from 45 MVA ONAN up to 75 MVA ONAF2.
Insulation levels shown include 350 kVp BIL on the HV winding, 200 kVp on the LV winding, and 150 kVp on the tertiary winding. The transformer uses ASTM D3487 Type II mineral oil and is shown with approximate total mass of 182,864 lb, shipping weight without oil of 126,764 lb, and oil volume of 5,283 gallons.
Per the proposal, Factory Acceptance Testing was completed, and the unit was shipped to the U.S. in late 2025 and placed into storage in accordance with Siemens layup procedures.
Highlights
- One (1) new Siemens Energy substation power transformer
- 45 / 60 / 75 MVA ratings, ONAN / ONAF / ONAF2
- 69 kV HV / 34.5 kV LV / 13.8 kV tertiary
- Three-phase, oil-immersed, utility substation design
- Vector group: YNyn0(d1)
- High-side DETC, SEI 800A-72kV, 5-position
- Copper windings
- Mineral oil insulating fluid
- IEEE C57.12.00 design basis
- Siemens Energy serial no. 461316
- Year of manufacture: 2025
Specifications
Electrical
- Rating: 45 / 60 / 75 MVA
- Cooling rating basis: ONAN / ONAF / ONAF2
- Frequency: 60 Hz
- Phases: 3
- HV winding: 69,000 V
- LV winding: 34,500 V
- Tertiary winding: 13,800 V
- Winding connections: Wye-Grounded / Wye-Grounded / Delta
- Vector group / phase displacement: YNyn0(d1)
- DETC: SEI 800A-72kV, 5-position
- Tap range: 2 x ±2.5%
- Nominal tap voltage: 70 kV
- HV tap positions: 72,450 / 70,725 / 69,000 / 67,275 / 65,550 V
- HV current at ONAN: 359 / 367 / 377 / 386 / 396 A
- HV current at ONAF2: 598 / 612 / 628 / 644 / 661 A
- LV current: 753 A ONAN / 1,255 A ONAF2
Cooling / Fluid
- Cooling type: ONAN / ONAF / ONAF2
- Fans: Yes
- Insulating fluid: Mineral oil
- Oil type: ASTM D3487 Type II
- Oil volume: 5,283 gal
- PCB statement: Contains no detectable PCB level at manufacture (<2 ppm)
Insulation / BIL
- HV winding BIL: 350 kVp
- LV winding BIL: 200 kVp
- Tertiary winding BIL: 150 kVp
- BIL windings (HV/LV/HV-N/LV-N/TV): 350 / 200 / 200 / 200 / 110 kV
- BIL bushings (HV/LV/HV-N/LV-N/TV): 350 / 350 / 350 / 350 / 150 kV
Losses / Impedance
- Impedance at mid tap, 85°C: 7.5% on 45 MVA ONAN base
- Impedance tolerance: -3% / +5%
- Expected no-load losses at 20°C: approx. 41 kW
- Expected load losses at 45 MVA ONAN: approx. 81 kW
- Expected load losses at 60 MVA ONAF: approx. 144 kW
- Expected load losses at 75 MVA: approx. 224 kW
- Note: Proposal states final warranted loss values to be confirmed upon FAT completion.
Weights / Shipping
- Approx. total mass: 182,864 lb
- Shipping weight without oil: 126,764 lb
- Untanking weight: 101,413 lb
- Core & coils assembly: 82,673 lb
- Tank & fittings: 34,172 lb
- Oil weight: 38,081 lb
- Altitude design: 1,000 m.a.s.l.
- Ambient range: -40°C to +40°C
- Temperature rise: 65°C
- Seismic design: IEEE 693 Medium
- Maximum wind speed: 90 mph
Included / Packaging
- Included: transformer, high-side DETC, cooling fans for ONAF/ONAF2 stages, CT provisions as shown on nameplate, bushings, oil preservation system, and standard accessories per Siemens Energy design. Proposal also references FAT report and engineering drawings/addenda.
- Package / crate number: TBD from shipping documents
- Shipping dimensions: TBD from shipping drawing not included in this upload set
- Gross shipping weight: 126,764 lb without oil
- Net / operating weight: 182,864 lb total mass
- Shipping note: shipped to U.S. / Baltimore port per proposal; inland freight to final site by buyer.
Terms
Subject to prior sale. Technical details are based on Siemens Energy documentation. Contact CTG Power Systems for pricing, delivery status, supporting documents, and commercial terms.
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