Abstract: A device for locating faults on the lines of electrical power distribution systems, including generally a variable impedance means adapted for connection in series with an electrical power line, and means for switching such variable impedance means between a first low impedance value when an initial current I.sub.1 of predetermined level flows on the power line for a predetermined period of time to enable detection of a fault condition, and a second high impedance value which limits the flow of current to a low level I.sub.2. A meter or other indicating device provides a reading of the current I.sub.1 to determine if a fault condition exists. In this fashion, the fault locator device limits both the magnitude and the time duration of the current when testing for a fault, so as not to adversely effect any system components.

Abstract: A selected point in an electric power system is monitored for subsequent fault analysis. The voltage and current at the point is continuously sampled with samples for a predetermined period of time being temporarily stored in memory. In response to a Fault Event, voltage and current samples at differing sample rates and for differing periods of time are recorded. Voltage and current samples after a Cold Load Pickup are recorded, also the recorded samples allow later analysis of the fault and identification of the cause of the fault.