150 kV 250 MVA Power Transformer

Introducing our advanced 250 MVA Step-Up Transformer, designed for robust outdoor installations and built to meet the highest standards of performance and reliability. This three-phase, oil-immersed transformer features a high voltage rating of 150 kV and a low voltage rating of 18 kV, with a unique 35 kV neutral winding, and is engineered according to the EN 60076-1 standard.

Key Specifications:

• Power Rating: 250 MVA
• High Voltage (HV): 150 kV
• Low Voltage (LV): 18 kV
• Neutral Winding: 35 kV
• Cooling Type: OFAF (Oil Forced Air Forced)
• Cooling System Layout:
  • Coolers: Hinged
  • Connection Cabinet: Hinged
  • Cooling System Control Cabinet: Separate from the transformer tank
  • Cooling System Control Cabinet Features:
    • Power Supply: Dual-source with automatic switch
    • Protection: Circuit breakers for fan motors and oil pump
    • Temperature Maintenance: Automatic, climate-controlled
    • Degree of Protection: IP55 (GOST 14254-96 / IEC 60529:2013)
    • Alarm: Door opening and current protection

Voltage Ratings and Withstand Capacities:

• Full Wave Lightning Impulse (LI):
  • HV: 550 kV (peak)
  • LV: 125 kV (peak)
• Chopped Wave Lightning Impulse (LIC):
  • HV: 600 kV
  • LV: 150 kV
• Short-Duration Power-Frequency Withstand Voltage (1 min, rms):
  • HV (ph-ground/ph-ph): 230/275 kV
  • LV: 50 kV
  • Neutral HV: 85 kV

Embedded Current Transformers (CTs):

• HV CTs:

  • Rated Primary Current: 750-1000-1500-2000 A
  • Rated Secondary Current: 5 A
  • Accuracy: 10P
  • Accuracy Limit Factor (ALT/FS): 25
  • Rated Secondary Load: 30 VA
  • Quantity: 2 per bushing

• Neutral CTs:

  • Rated Primary Current: 200/300/400/600 A
  • Rated Secondary Current: 5 A
  • Accuracy: 10P
  • Accuracy Limit Factor (ALT/FS): 25
  • Rated Secondary Load: 30 VA
  • Quantity: 2 per bushing

Bushing and Connection Details:

• 150 kV HV: Bushings with hard insulation RIP and external silicon insulation
• 35 kV Neutral: Bushings with hard insulation RIP and external silicon insulation
• 18 kV LV: Oil-air, porcelain
• Bushing Testing: Cantilever load test as per IEC 60137
• Contact Parts: Equipped for flexible stranded connections

Safety and Maintenance Features:

• Gas Relay: Signals gas emission and shuts down the transformer in case of low oil level or accelerated oil flow
• Oil Level Indicator: Remote-controlled with signal contacts for maximum and minimum levels
• Drying Air System: Maintenance-free intelligent dehumidifier
• Shut-Off Valve: Includes valve position signaling and indicator
• Safety Valves: Two valves with operation signaling contacts

Performance and Environmental Specifications:

• Transformer Performance Coefficient (PEI): Meets ecodesign level 2 requirements
• Temperature Tolerances:
  • Oil in Upper Layers: ≤ 60°C
  • Average Winding Temperature: [Temperature not specified]
  • Hottest Winding Part: [Temperature not specified]
• Ambient Air Temperature:
  • Maximum Operating: +45°C
  • Minimum Operating: -40°C
  • Annual Average: ≤ +20°C
• Degree of Air Pollution: Class 3 (PUE-2017 or equivalent)
• Seismic Stability: MSK-64 points, not less than 6
• Installation Altitude: Up to 1000 m above sea level

Physical Dimensions:

• Length: 6500 mm
• Width: 3000 mm
• Height: 4200 mm

Weight:

• Transport: 148 t
• Full: 172 t
• Oil: 26 t
• Active Part: 127 t
• Removable Tank Part: 16 t

This 250 MVA Step-Up Transformer combines high performance, reliability, and advanced technology to meet the demanding needs of modern electrical grids. For more information or to schedule a consultation, please contact us.