Advanced DC breaker tech speeds up protection, cuts energy loss

Researchers at Oak Ridge National Laboratory (ORNL) have developed the world’s fastest medium-voltage direct current (DC) circuit breaker, leveraging semiconductor technology—specifically thyristors—to overcome limitations of traditional mechanical breakers. Unlike alternating current (AC), DC lacks a natural zero-crossing point to interrupt current flow, making mechanical breakers slow and prone to arcing and fire risks during faults. The new semiconductor-based breaker can interrupt 1,400 volts in under 50 microseconds, which is four to six times faster than previous thyristor-based systems, significantly enhancing safety and reliability for DC power grids. The design is scalable by connecting multiple breaker units in series, successfully tested up to 1,800 volts, with ongoing work targeting 10,000 volts to meet the demands of high-voltage DC grids. This breakthrough is critical for modern energy infrastructure, particularly for sectors like AI data centers and advanced manufacturing that benefit from DC’s higher efficiency, lower transmission losses, and support for multi-direction