Medium voltage DC vacuum circuit breaker

The increased use of directed current (DC) as an enabler for the integration of renewable sources gains rising interest also for power transmission and distribution networks. Some preliminary installations showed some benefit of this technique compared with alternating current (AC) and pushed the development of switchgear for high (HV) and medium voltage (MV) DC grids. Several techniques able to provide DC interruption have been proposed in publications and are briefly described. The article focusses on actual development activities and tests of a medium voltage DC circuit breaker based upon the concept of current injection using a medium voltage vacuum interrupter.