Advanced 2x25kV AC Traction Power Supply Systems
Powering heavy-haul and high-speed railway networks efficiently using auto-transformer (AT) technology over long distances with reduced electromagnetic interference.
System Quick Status
- Feeding Voltage: 50 kV System (2 x 25 kV)
- Phase Angle: Out of phase (+25kV / -25kV)
- Transmission: Reduced line losses & drop
- Application: Heavy Haul & Bullet Trains
Why 2x25kV AT System?
Designed for modern heavy traffic railways demanding higher power transfer capabilities.
Higher Power Capacity
Delivers double the voltage to the pantograph section (50kV transmission) while supplying standard 25kV to rolling stock via Auto-Transformers.
Reduced Voltage Drop
Allows greater distance between Sub-Stations (TSS) due to lower current circulation and efficient power compensation.
Minimal Interference
Significantly reduces electromagnetic interference (EMI) on nearby telecommunication lines and signaling equipment.
Core Architecture & Working Principle
The 2x25kV system utilizes a feeder wire, overhead contact line (catenary), and a rail return system connected through Auto-Transformer (AT) sites spaced strategically along the track alignment.
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Contact Wire (+25kV): Feeds power directly to the electric locomotive pantograph.
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Feeder Wire (-25kV): Carries out-of-phase current to balance loads over distance.
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Auto-Transformers (AT): Step down the 50kV transmission back to 25kV supplies for locomotives.
Typical Electrified Heavy-Haul Track Corridor
Technical Specifications
Standard parameters applied in modern high-speed rail electrification projects.
| Parameter | Nominal Value | Design Function |
|---|---|---|
| System Voltage | 50 kV (Between Feeder & OCL) | Long distance power transmission |
| Pantograph Voltage | 25 kV (Between OCL & Rail) | Locomotive traction supply |
| Auto-Transformer Spacing | 10 km to 15 km intervals | Voltage stabilization & balancing |
| Traction Substation (TSS) Spacing | 40 km to 60 km | Bulk power intake from grid utilities |