Traction

Transformers play a crucial role in traction systems, which are used in electric railways, trams, metro systems, and electric vehicles. Their primary functions include voltage transformation, isolation, and power distribution. Here’s how transformers are used in traction applications:

1. Traction Substation Transformers

These transformers step down high-voltage electricity from the grid (e.g., 132 kV, 66 kV, or 25 kV) to the appropriate voltage needed for railway traction (e.g., 25 kV AC or 750V DC). They ensure efficient power supply for trains.

2. Onboard Transformers (for Electric Locomotives)

In AC electric locomotives, onboard transformers step down the high-voltage AC (typically 25 kV) from the overhead catenary to a lower voltage suitable for traction motors. These transformers also help in power distribution to auxiliary systems.

3. Autotransformers in 2×25 kV Systems

For long-distance railway electrification, a 2×25 kV autotransformer system is used. This system enhances efficiency by reducing transmission losses and improving voltage regulation over long distances.

4. Rectifier Transformers (for DC Traction)

In DC traction systems (like metros and trams operating at 750V, 1500V, or 3000V DC), rectifier transformers step down AC voltage and supply it to rectifiers, which convert it to DC for traction motors.

5. Auxiliary Transformers

These transformers provide power for non-traction loads, such as lighting, air conditioning, and control systems in locomotives and rail coaches.