Abstract: A method for detecting faults in a low voltage three-phase network including: checking if any of three phases of the three-phase network satisfies first conditions for a predetermined duration of time; if at least two phases satisfy the first conditions, detecting an inter-phase fault by checking if the current level in at least two phases exceed a threshold and if the corresponding current flows are in the same direction; if only one of the three phases satisfies the first conditions, for the phase which has satisfied the first conditions, checking if a second condition is satisfied and, in a positive case, detecting a mono-phase fault.

Abstract: A microgrid overcurrent protection device and a method for overcurrent protection of a microgrid. The protection device including a voltage controlled overcurrent detector for detecting an overcurrent above an overcurrent threshold and a phase directional detector arranged for current direction in a downstream or an upstream direction. The overcurrent threshold of the voltage controlled overcurrent detector is set at an upper overcurrent threshold when a measured voltage Vm is above a threshold voltage Vs and set at a lower overcurrent threshold when the measured voltage Vm is below the threshold voltage Vs. The device further includes a timer arranged for generating a trigger signal with a first delay time period when a downstream current direction and an overcurrent are detected and with a second delay time period when an upstream current direction and an overcurrent are detected.

Abstract: A method for detecting faults in a low voltage three-phase network including: checking if any of three phases of the three-phase network satisfies first conditions for a predetermined duration of time; if at least two phases satisfy the first conditions, detecting an inter-phase fault by checking if the current level in at least two phases exceed a threshold and if the corresponding current flows are in the same direction; if only one of the three phases satisfies the first conditions, for the phase which has satisfied the first conditions, checking if a second condition is satisfied and, in a positive case, detecting a mono-phase fault.

Abstract: A method for locating and clearing phase faults in a micro-grid in off-mode. The method includes determining a surveillance area of a microgrid having at least two busbars to monitor; determining all source feeders and load feeders of the surveillance area; acquiring measurement data comprising current magnitude for all source feeders and load feeders; and monitoring the at least two busbars in the surveillance area for a voltage dip in one of phase-to-phase or phase-to-neutral voltages. The method further includes, on detecting a voltage dip on the monitored busbars, determining a defect phase having a minimum phase-to-neutral voltage; and performing current analysis for the defect phase.

Abstract: A method for locating phase faults in a microgrid in off-grid mode. The method includes obtaining a grid topology of the microgrid having at least two busbars and determining the position of all circuit breaker position of the grid topology. Further, acquiring measurement data which includes current magnitude and voltage magnitude. Monitoring the at least two busbars for a voltage dip in one of phase-to-phase or phase-to-neutral voltages. On detecting a voltage dip, determining a defect phase having a minimum phase-to-neutral voltage value. And for the defect phase performing busbar analysis and feeder analysis, using phase-directional information.

Abstract: A method for locating and clearing phase faults in a micro-grid in off-mode. The method includes determining a surveillance area of a microgrid having at least two busbars to monitor; determining all source feeders and load feeders of the surveillance area; acquiring measurement data comprising current magnitude for all source feeders and load feeders; and monitoring the at least two busbars in the surveillance area for a voltage dip in one of phase-to-phase or phase-to-neutral voltages. The method further includes, on detecting a voltage dip on the monitored busbars, determining a defect phase having a minimum phase-to-neutral voltage; and performing current analysis for the defect phase.

Abstract: A method for locating phase faults in a microgrid in off-grid mode. The method includes obtaining a grid topology of the microgrid having at least two busbars and determining the position of all circuit breaker position of the grid topology. Further, acquiring measurement data which includes current magnitude and voltage magnitude. Monitoring the at least two busbars for a voltage dip in one of phase-to-phase or phase-to-neutral voltages. On detecting a voltage dip, determining a defect phase having a minimum phase-to-neutral voltage value. And for the defect phase performing busbar analysis and feeder analysis, using phase-directional information.

Abstract: A microgrid overcurrent protection device and a method for overcurrent protection of a microgrid. The protection device including a voltage controlled overcurrent detector for detecting an overcurrent above an overcurrent threshold and a phase directional detector arranged for current direction in a downstream or an upstream direction. The overcurrent threshold of the voltage controlled overcurrent detector is set at an upper overcurrent threshold when a measured voltage Vm is above a threshold voltage Vs and set at a lower overcurrent threshold when the measured voltage Vm is below the threshold voltage Vs. The device further includes a timer arranged for generating a trigger signal with a first delay time period when a downstream current direction and an overcurrent are detected and with a second delay time period when an upstream current direction and an overcurrent are detected.

Abstract: The electrical power distribution network comprises a medium-voltage feeder having an upstream end intended to be connected to a power source. The feeder includes at least first and second consecutive protection relays positioned along the feeder and defining the ends of a first element to be monitored. The first protection relay includes a search module configured to trip a breaker to interrupt the electrical power distribution: after a first time delay when the search module detects a single-phase permanent fault in a monitoring area of the first element; and after a second time delay longer than the first time delay when the search module detects a single-phase permanent fault in an additional monitoring area located downstream of the area.