Eliminating DC supply failures


Inexpensive AC to DC switching system

The technology

Long-distance electrical transmission brings flexibility to electrical supply, and allows remote renewable energy resources to be used instead of fossil fuels.

Increasingly, this long distance transmission relies on high voltage direct current (HVDC) power lines. These have distinct advantages over alternating current (AC) transmission systems: they are cheaper, lose less power during transmission and the pylons have a smaller footprint.

However it is costly to convert AC to DC power due to the high price of the DC circuit breakers, which contributes significantly to the overall capital cost of developing DC grids.

Researchers at the University of Birmingham have developed an alternative which provides protection from DC fault currents and fast DC fault control.

The technology reduces fault current to zero, through a novel routing managed by a voltage sourced converter and so eliminates power supply failures during DC transmission.

The device is protected by a suite of global patents.


  • Replaces the need for expensive switching systems
  • Provides a simple circuit breaker
  • Reduced complexity in HVDC power grids
  • No contact wear due to arcing


  • Switching AC to DC current at the interface of AC and DC transmission systems

Lead scientist

  • Dr Xiao-Ping Zhang, Reader of Electrical Power Systems and Director of Institute of Energy Research & Policy in the School of Electronic, Electrical and Computer Engineering, University of Birmingham.