System and method for managing electric grid

A system for managing an electric grid with a substation having a transformer with a transformer neutral grounded via a grounding impedance, the system comprising:

• a current sensing unit associated with the transformer neutral, wherein the current sensing unit is configured to measure a ground current or a neutral current at the transformer neutral;
• one or more traveling wave fault recording units installed on one or more feeder lines connected to the transformer, each of the one or more traveling wave fault recording units configured to detect and record arrival times of traveling wave signals generated by a fault event in the corresponding feeder line;
• one or more high-frequency sensors positioned at the feeder line exit points or at the interconnections of busbars within the substation;
• a processing arrangement in communication with the current sensing unit, the one or more traveling wave fault recording units, and the one or more high-frequency sensors, the processing arrangement configured to:
• receive information about the ground current or the neutral current from the current sensing unit, and the arrival times of traveling wave signals from the one or more traveling wave fault recording units;
• detect an earth fault or a differential mode fault in any of the one or more feeder lines or at the substation based on the received information about the ground current or neutral current;
• and
• compute, in response to detection of an earth fault or a differential mode fault, a fault location of the fault event in the one or more feeder lines based on the received information about the arrival times of traveling wave signals and the detected transient signals.

A method for managing an electric grid with a substation having a transformer with a transformer neutral thereof grounded via a grounding impedance, the method comprising:

• measuring a ground current or a neutral current at the transformer neutral using a current sensing unit associated therewith;
• detecting and recording arrival times of traveling wave signals generated by a fault event in a corresponding one of one or more feeder lines, using one or more traveling wave fault recording units installed on the one or more feeder lines connected to the transformer;
• sensing, by one or more high-frequency sensors positioned at the feeder line exit points or at the interconnections of busbars within the substation, high-frequency signals associated with the fault event;
• receiving, by a processing arrangement in communication with the current sensing unit, the one or more traveling wave fault recording units, and the one or more high-frequency sensors information about the ground current or the neutral current from the current sensing unit;
• and arrival times of traveling wave signals from the one or more traveling wave fault recording units;
• detecting an earth fault or a differential mode fault in any of the one or more feeder lines or at the substation based on information about the ground current or neutral current;
• and
• computing, in response to detection of an earth fault or a differential mode fault, a fault location of the fault event in the one or more feeder lines based on information about the arrival times of traveling wave signals and the detected transient signals.