110kV Power Transformer for transfer power between the transmission grid and distribution systems

110kV Power Transformer

110 kV power transformer is a high-voltage transformer commonly used in transmission and sub-transmission networks to transfer power between the transmission grid and distribution systems.

Typical Specifications
·High-voltage side: 110 kV
·Low-voltage side: 35 kV, 33 kV, 22 kV, 11 kV, or 10 kV
·Power rating: Typically 10 MVA to 250 MVA
·Frequency: 50 Hz or 60 Hz
·Cooling methods: ONAN, ONAF, OFAF, OFWF
·Insulation: Oil-immersed (most common)
·Tap changer: Usually On-Load Tap Changer (OLTC)

Common Applications
·Transmission substations
·Utility grid interconnections
·Large industrial facilities
·Renewable energy plants (wind and solar farms)
·Urban and regional power distribution systems

Example Nameplate Data
·Rated Power 63 MVA
·HV Voltage 110 kV
·LV Voltage 35 kV
·Frequency 50 Hz
·Cooling ONAN/ONAF
·Vector Group YNd11
·Impedance 10–15%

Main Components
·Laminated magnetic core
·High-voltage windings (110 kV)
·Low-voltage windings
·Transformer tank
·Mineral insulating oil
·Conservator tank
·Cooling radiators and fans
·High-voltage bushings
·On-load tap changer (OLTC)
·Protection systems:
·Buchholz relay
·Pressure relief device
·Oil temperature indicator
·Winding temperature indicator
·Differential protection relay

Typical Substation Configuration
110 kV / 35 kV, 63 MVA Transformer
110 kV Transmission Line → Power Transformer → 35 kV Switchgear → Distribution Feeders

Advantages of 110 kV Transmission
·Reduced transmission losses
·Higher power transfer capability
·Improved voltage regulation
·Efficient supply to large load centers
·Suitable for regional transmission networks

110 kV transformers are among the most common substation transformers worldwide, serving as the interface between high-voltage transmission systems and medium-voltage distribution networks.