Method for Detection and Limitation of Short-Circuit Currents for Semiconductor Circuit Breakers in LVDC Grids Using a Pre-Saturated Inductor

This paper introduces an innovative non-destructive device designed to detect and limit short-circuit currents in LVDC grids. The proposed solution utilizes a transformer fully saturated by a permanent magnet during normal operation. When a short-circuit condition occurs, the transformer desaturates, reducing the rise in current and triggering the detection and protection mechanism. The structure and functionality of the device, along with the design criteria, are discussed. Additionally, optimization measures are presented, examined, and validated. Experimental results from the advanced device prototype demonstrate its effectiveness in detecting and limiting overcurrents. The device features a stable tripping threshold and can safely and reliably interrupt even low time constant capacitive short-circuits. This hardware-based detection solution is ideally suited for installation in a semiconductor circuit breaker.