One of the longest-standing challenges in electrical engineering, that of successfully designing and developing a practical high voltage high current DC circuit breaker, has finally been cracked by ABB after years of  research, functional testing and simulation in its R&D laboratories.

This breaker represents the solution to a technical problem that has been unresolved for over a hundred years. The lack of it was one of the deciding factors in the battle to establish AC rather than DC as the best medium for elctrical power distribution. 

This breaker, a ‘hybrid’ design, combines mechanical and power electronics switching that enables it to interrupt power flows on a GW scale within 5 milliseconds. Thisis remarkably fast for an electromechanical device, but speed is not the only criterion. The challenge was to do it at a useful speed with minimal operational losses and this has been achieved by combining advanced ultrafast mechanical actuators with ABB’s own versionof IGBT valve technology.

In terms of significance, this breaker is a game changer. It removes a major stumbling block in the development of HVDC transmission grids that ultimately will enable interconnection and load balancing among HVDC power superhighways integrating renewables and transporting bulk power across long distances with low losses. DC grids will enable sharing of resources like lines and converter stations that provides reliability and redundancy in a power network in an economically viable manner. The next step, says ABB, is to install the breaker in pilot installations.