The on-load tap-changing (OLTC) oil-immersed transformer is a critical component in power distribution
systems, designed to regulate voltage levels while maintaining continuous power supply. This type of
transformer is equipped with a tap changer that adjusts the winding turns ratio under load, ensuring stable
output voltage despite fluctuations in input voltage or load conditions. The 35/0.4 kV rating indicates it
steps down high-voltage electricity from 35 kV to low-voltage 0.4 kV, making it suitable for industrial and
commercial applications.
The transformer's core is typically made of high-grade silicon steel, minimizing iron losses, while the windings
are constructed from copper or aluminum to reduce copper losses. The OLTC mechanism allows for real-time
voltage adjustment, usually within a range of ±10% to ±15%, ensuring optimal performance and compatibility
with various load requirements. This feature is particularly useful in areas with unstable grid conditions.
Insulation is a key aspect of its design, with the windings immersed in mineral oil to enhance cooling and
insulation properties. The oil also acts as a dielectric medium, preventing internal arcing and extending the
transformer's lifespan. Additionally, the transformer is equipped with protective devices such as Buchholz
relays and pressure relief valves to ensure safe operation.
