Power Transformer (Transmission Grade)

A Power Transformer (Transmission Grade) is a critical component in electrical power systems designed to transfer electrical energy between high-voltage transmission networks while maintaining power quality and reliability. These transformers are typically installed in generation plants, transmission substations, and grid interconnection points.

Unlike distribution transformers, transmission-grade power transformers handle very large power ratings and operate continuously under high-voltage conditions. They are designed with advanced insulation systems, cooling arrangements, protection features, and monitoring equipment to ensure reliable operation in national and regional power grids.

These transformers increase generator voltage for efficient long-distance transmission and reduce transmission voltage at substations for distribution networks.

Key Features

• High-voltage transmission capability
• Large MVA power ratings
• High efficiency and low power losses
• Oil-immersed cooling system
• On-load tap changer (OLTC) for voltage regulation
• Advanced insulation system
• Buchholz relay protection
• Temperature monitoring system
• Pressure relief devices
• Online condition monitoring options
• High short-circuit withstand capability
• Long operational lifespan

Common Applications

• Power Generation Plants
• Transmission Substations
• Grid Switching Stations
• Utility Power Networks
• Renewable Energy Grid Connections
• Industrial Power Plants
• Large Infrastructure Projects
• National Electricity Grids

Typical Specifications

• Capacity: 10 MVA to 1000+ MVA
• Voltage Levels:
  • 33 kV
  • 66 kV
  • 132 kV
  • 220 kV
  • 400 kV
  • 765 kV (extra high voltage systems)
• Cooling Methods: ONAN, ONAF, OFAF, OFWF
• Frequency: 50 Hz / 60 Hz

Common Types

• Step-Up Power Transformer
• Step-Down Power Transformer
• Generator Transformer (GSU)
• Auto Transformer
• Three-Phase Power Transformer
• Extra High Voltage (EHV) Transformer
• Ultra High Voltage (UHV) Transformer

Popular Manufacturers

• Hitachi Energy
• Siemens Energy
• GE Grid Solutions
• Schneider Electric
• Toshiba Energy Systems
• Hyundai Electric
• Mitsubishi Electric
• CG Power
• TBEA
• Bharat Heavy Electricals Limited (BHEL)