Systems, methods, and apparatus for fault detection and interruption in power lines are provided. Circuitry is implemented via software and hardware that is configured to sense an operational aspect of a power line, such as current levels in a three-phase power line, and apply signal processing to the sensed operational aspect to detect faults including different types of faults such as transient and steady state faults and can also be configured to identify the type of fault. Information on the fault and the identification of the type of fault can be displayed, stored, or some other output operation can be implemented. Circuitry can be implemented to provide digital signal processing and analog signal processing to, for example, independently and in parallel (e.g., redundant operation) detect faults and respond to faults as they occur (i.e., in real time).