US' high-speed breaker for DC electricity boom passes 1,800-volt testing

Researchers at Oak Ridge National Laboratory (ORNL) have developed a breakthrough medium-voltage semiconductor circuit breaker capable of interrupting direct current (DC) at voltages up to 1,800 volts and clearing faults in less than 50 microseconds. This speed is critical because unlike alternating current (AC), DC lacks natural zero-crossing points, making traditional mechanical breakers too slow and unsafe for high-voltage DC systems. The new breaker uses affordable thyristor semiconductors combined with a novel external circuit to forcibly stop current flow, preventing dangerous electrical arcs and making semiconductor breakers economically competitive for the first time. This innovation paves the way for widespread adoption of high-power DC grids, which are more efficient and better suited to integrate renewable energy sources like solar panels and batteries. The ORNL team has demonstrated scalability by linking breakers in series and is working toward systems capable of handling up to 10,000 volts to meet future energy demands, including those from AI data centers. By enabling safer, faster