TKDG Air-Core Reactor Empowers 12-Pulse Rectifier System: Harmonic Mitigation Solution for Rail Transit Traction Power Supply
Ⅰ. Application Scenario
When 12-pulse rectifier units operate in subway traction substations, they tend to generate characteristic harmonics such as the 11th and 13th orders. This leads to excessive contact line voltage waveform distortion (measured at 8.5%), impacting power supply quality and the safety of rolling stock equipment.
II. Core Solution
Deploy TKDG-type outdoor epoxy-cast air-core reactors to achieve efficient harmonic absorption and system optimization.
III. Technical Highlights
- Innovative Reactor Design
- Vertical Stacked Winding Structure: Unique spatial layout design reduces footprint while ensuring inductance accuracy, accommodating compact substation space requirements.
- 120°C Continuous Operation Capability: Epoxy resin vacuum casting process provides complete encapsulation insulation, enabling stable long-term operation under natural air cooling at high temperatures. Maintenance-free cycle reaches 20 years.
- System-Level Harmonic Mitigation
- 24-Pulse Rectification Collaborative Mitigation: Reactors and rectifier units form a complete mitigation unit:
▸ 12-pulse rectification → Generates 11th/13th/23rd/25th harmonics.
▸ Upgrade to 24-pulse rectification → Eliminates 23rd/25th harmonics.
▸ TKDG Reactor → Specifically absorbs residual 11th/13th characteristic harmonics. - Key Performance Parameters
|
Indicator |
Pre-Mitigation |
Post-Mitigation |
Improvement Rate |
|
Contact Line Voltage THD |
8.5% |
2.1% |
75.3% |
|
Characteristic Harmonic Content Rate |
>5% |
<0.8% |
>84% |
|
Continuous Operation Temp. Rise (°C) |
- |
≤70 K |
- |
IV. Implementation Benefits
- Enhanced Power Supply Safety: Voltage THD meets/complies with the requirement (≤4%) of National Standard GB/T 14549-93 "Power Quality - Harmonics in Public Supply Network", reducing the risk of malfunction in locomotive control systems.
- Energy Efficiency Optimization: Reduced harmonic currents lower line losses. Measured comprehensive energy efficiency of the traction system improved by 3%-5%.
- Space and Cost Advantages:
▸ Vertical structure saves 30% installation area.
▸ Natural cooling design saves 45% in operation and maintenance costs compared to forced-air cooling solutions.
V. Engineering Validation
- 11th harmonic current reduced from 312 A to 58 A.
- 13th harmonic current reduced from 285 A to 62 A.
- Failure rate of capacitor banks and relay protection equipment reduced to zero.
Summary of Solution Advantages: Achieves a leap in 12-pulse system power quality to the level of a 24-pulse system through precise absorption of characteristic harmonics using topology optimization, avoiding the need for capacity expansion retrofits.
