Liquid Cooling Plates in HVDC Transmission: A Case Study

The Growing Demand for Efficient Cooling in HVDC Systems

As global electricity consumption rises, Flexible HVDC (High-Voltage Direct Current) transmission systems have become essential for efficient long-distance power transfer. The valve group, a core component of these systems, relies on power semiconductor devices (IGBTs, thyristors) that generate significant heat during operation.

The Thermal Challenge in HVDC Systems

• Semiconductor devices in HVDC converters produce high heat flux (500+ W/cm²)

• Prolonged exposure to temperatures above 150°C leads to device degradation, failures, and even explosions

• Traditional air cooling fails to meet cooling demands, causing:

  • Thermal throttling (reduced efficiency)

  • Increased failure rates (costly downtime)

  • Higher maintenance costs

Liquid cooling plates have emerged as the optimal solution, ensuring stable, efficient, and long-lasting HVDC performance.

Why Liquid Cooling Outperforms Air Cooling in HVDC Systems

Heat Transfer Efficiency Comparison

Key Advantages of Liquid Cooling Plates

✔ 25,000 W/m²·°C Heat Transfer – 35x more efficient than air cooling
✔ Prevents Thermal Runaway – Maintains safe operating temperatures (<85°C for IGBTs)
✔ Uniform Heat Distribution – Eliminates hot spots, extending device lifespan
✔ Compact & Lightweight – Ideal for high-density HVDC valve modules
✔ Energy Efficient – Reduces cooling power consumption by 40-60%

Real-World Application: Liquid Cooling in HVDC Transmission

Case Study: Offshore Wind Farm HVDC Link

Challenge:

• High-power IGBT modules overheating in salt-rich, humid environments

• Frequent shutdowns due to thermal stress

Solution:

• Sealed liquid cooling plates with corrosion-resistant materials

• Microchannel cooling for maximum heat dissipation

Results:
✅ 30°C lower operating temperatures (preventing thermal throttling)
✅ 50% reduction in failure rates
✅ Zero unplanned outages in 24 months

Case Study: Urban HVDC Power Transmission

Challenge:

• Space constraints in urban substations

• Air cooling too noisy & inefficient

Solution:

• Modular liquid cooling plates integrated into valve towers

• AI-driven flow control for dynamic cooling

Results:
✅ 25% smaller footprint vs. air-cooled systems
✅ Near-silent operation (ideal for populated areas)
✅ 20% higher energy efficiency

Future Trends: Next-Gen Liquid Cooling for HVDC

1. Two-Phase Cooling

• Uses boiling/condensation cycles for 50% higher efficiency

• Already being tested in ultra-high-voltage (UHV) converters

2. Nanofluid-Enhanced Cooling

• Graphene & carbon nanotube coolants improve heat transfer by 3x

• Extends component lifespan by reducing thermal cycling stress

3. Smart Predictive Cooling with AI

• Machine learning algorithms predict heat loads and adjust cooling in real time

• Prevents thermal fatigue in IGBT modules

Conclusion: Why Liquid Cooling is the Future of HVDC Systems

✔ 25,000 W/m²·°C heat transfer (vs. 1,500 for air cooling)
✔ Prevents IGBT failures at 150°C+
✔ Reduces maintenance costs by 50%
✔ Scalable for next-gen UHV transmission