Image for illustrative purposes

China has introduced the world’s largest smart DC transformer, rated at 750 MVA, aimed at stabilizing the electricity grid amid growing renewable energy integration. The transformer will be part of China’s west-to-east ultra-high-voltage DC (HVDC) transmission system, spanning 2,370 km from Gansu to Zhejiang, and is expected to deliver over 36 billion kWh of electricity annually.

The move comes after a near-grid disruption in Xinjiang last year, when fluctuating wind power triggered low-frequency oscillations that threatened wider network stability. Traditional AC transmission systems were unable to respond quickly enough to these rapid changes.

Developed by Changzhou Xidian Transformer, a subsidiary of China XD Group, the flexible DC transformer can handle sudden changes in wind and solar power input, monitor internal temperatures with fibre-optic sensors, and reduce energy losses through advanced magnetic field management. The system successfully passed stress tests, including lightning strikes and rapid AC/DC switching.

Experts note that HVDC systems are more efficient than AC for long-distance electricity transmission and provide finer control over power flows, making them crucial for grids with high renewable penetration. This new transformer represents the first ultra-high-voltage flexible DC transmission system combining long-distance, high capacity, and real-time control.

Looking forward, researchers are exploring multi-terminal DC networks, which could dynamically route electricity across regions, improving the reliability and predictability of renewable energy on a large scale.

Source: interestingengineering.com