66 kV power transformer is a high-voltage transformer used in electrical transmission and sub-transmission systems. It typically connects a 66 kV network to lower voltage distribution systems or industrial loads.
Typical Specifications
·High-voltage side: 66 kV
·Low-voltage side: Commonly 33 kV, 22 kV, 11 kV, or 6.6 kV
·Power rating: Usually from 5 MVA to 100 MVA or higher
·Frequency: 50 Hz or 60 Hz
·Cooling: ONAN, ONAF, OFAF, or OFWF
·Insulation: Oil-immersed or dry-type (less common at this voltage)
Typical Applications
·Utility substations
·Industrial power distribution
·Renewable energy grid connections
·Regional transmission networks
Example Transformer Rating
·Rated Power: 25 MVA
·HV Voltage: 66 kV
·LV Voltage: 11 kV
·Frequency: 50 Hz
·Cooling: ONAN/ONAF
·Vector Group: Dyn11
·Impedance: 10–12%
Main Components
·Magnetic core
·HV and LV windings
·Transformer tank
·Insulating oil
·Conservator
·Radiators and cooling fans
·Bushings
·On-load tap changer (OLTC)
·Protection devices (Buchholz relay, pressure relief device, temperature indicators)