Branch circuit protection for DC systems

We present a new approach for protecting DC power distribution circuits against faults and negative incremental impedance instabilities. Like a circuit breaker, the device is passive until a fault occurs. Unlike a circuit breaker, the device operates in current limiting mode or in impedance transformation mode, according to the system requirements, and it can serve as a power buffer during transient upstream disruptions. The approach permits coordination between hierarchical levels of protection, it enables system reconfiguration, and it increases system stability. All three types of protection are achieved automatically by the controller based solely on local current and voltage measurements. The efficacy of this solution has been demonstrated through simulation. System stability with and without the proposed protection system has been analyzed according to the Brayton-Moser mixed potential criterion. The approach is proven to increase the stability of the systems in all configurations.