ABB has found a way to interrupt direct current, solving a 100-year-old electrical engineering puzzle. The power and automation technology group headquartered in Zurich, Switzerland, has developed a circuit breaker for high-voltage direct current (HVDC). It combines fast mechanics with power electronics and will be capable of interrupting power flows equivalent to the output of a large power station within five milliseconds.

The development removes a barrier to the development of DC transmission grids, which will enable the efficient integration and exchange of renewable energy. DC grids will improve grid reliability and enhance the capability of existing AC (alternating current) networks. ABB is in discussions with power utilities to identify pilot projects.