Abstract: Systems and methods for monitoring electrical contacts are provided. One method includes calculating an impedance of an electrical contact based on an electrical signal applied to the electrical contact and a measured electrical signal after passing through the electrical contact. The method also includes determining a condition of the electrical contact using the calculated impedance.

Abstract: A method and system for a power distribution system are provided. The method includes determining at a central controller normal mode configuration settings for a plurality of circuit breakers of the power distribution system and determining at the central controller alternate mode configuration settings for the plurality of circuit breakers of the power distribution system. The method further includes controlling with the central controller the operation of the plurality of circuit breakers based on the normal mode configuration settings and the alternate mode configuration settings.

Abstract: A centrally controlled protection system is provided. The system includes a plurality of circuit breakers, a plurality of modules, and a central computer. Each of the plurality of breakers are in electrical communication with a respective one of the plurality of modules. The central computer is in communication with each of the plurality of modules via a network. The central computer controls the plurality of circuit breakers in either a normal mode or a reduced energy let-through mode.

Abstract: A method of operating a relay device, in an electrical circuit comprising first and second main circuit breakers, and a bus tie circuit breaker connecting the first and second main circuit breakers, the method comprising computing a first positive sequence current phasor for the first main circuit breaker and a second positive sequence current phasor for the second main circuit breaker computing a first positive sequence voltage phasor for the first main circuit breaker and a second positive sequence voltage phasor for the second main circuit breaker; computing a correction of the first positive sequence voltage and second positive sequence voltage to a line-to-neutral phase angle reference if there is any rotation in a potential transformer connection; determining a fault has occurred when a magnitude of a current through at least one of the first main circuit breaker or the second main circuit breaker exceeds a predetermined threshold; determining a phase angle difference by comparing the phase angle of the

Abstract: A method of operating a relay device, the method comprising the steps of: providing main circuit-breakers and a bus-tie-breaker connecting the main-circuit-breakers; defining a partial-differential-zone comprising a main circuit breaker and the bus-tie breaker; assigning a first value to the direction of the fault current flowing into the partial differential zone;—assigning a second value to the direction of the fault currents flowing out of the partial-differential-zone, wherein the first value is not equal to the second value;—comparing the values assigned to the fault currents; determining if the fault currents are flowing into the partial differential zone; and determining if at least two of the fault-currents is flowing in a different direction with respect to the partial-differential-zone wherein one of the fault currents is flowing into the partial-differential-zone and one of the fault currents is flowing out of the partial differential zone.

Abstract: There is provided a method of controlling circuit breakers in a multi-phase power system. The method includes (a) recognizing a concurrent presence of a first fault in a first phase of the power system and a second fault in a second phase of the power system, where the power system includes a first circuit breaker situated to conduct a fault current between the first and second phases, (b) controlling a second circuit breaker to open so that the fault current is interrupted, where the second circuit breaker, when closed, provides current to the first circuit breaker, and (c) controlling the first circuit breaker to remain closed until the second circuit breaker is opened.

Abstract: A method of operating a relay device, the method comprising the steps of: providing main circuit-breakers and a bus-tie-breaker connecting the main-circuit-breakers; defining a partial-differential-zone comprising a main circuit breaker and the bus-tie breaker; assigning a first value to the direction of the fault current flowing into the partial differential zone; -assigning a second value to the direction of the fault currents flowing out of the partial-differential-zone, wherein the first value is not equal to the second value; -comparing the values assigned to the fault currents; determining if the fault currents are flowing into the partial differential zone; and determining if at least two of the fault-currents is flowing in a different direction with respect to the partial-differential-zone wherein one of the fault currents is flowing into the partial-differential-zone and one of the fault currents is flowing out of the partial differential zone.

Abstract: A method of operating a relay device, the method comprising the steps of: computing positive-sequence first and second current-phasor for the first and second main circuit-breakers and computing currents from phasors, and the bus-tie-breaker; computing positive-sequence voltage for the bus-tie-breaker; triggering a method when at least one fault current at the bus-tie-breaker exceeds a threshold, without the presence of a fault on one of the feeders; determining whether the fault is internal or external, wherein the fault is internal if the positive-sequence current of the first and second main circuit breakers is in phase; and wherein if the positive-sequence current through the first main circuit breaker is not in-phase with the positive-sequence current through the second main circuit breaker, the fault is external to the bus; determining whether the fault is on a first or second side of the tie circuit; and locating the fault.

Abstract: A centrally controlled protection system is provided. The system includes a plurality of circuit breakers, a plurality of modules, and a central computer. Each of the plurality of breakers are in electrical communication with a respective one of the plurality of modules. The central computer is in communication with each of the plurality of modules via a network. The central computer controls the plurality of circuit breakers in either a normal mode or a reduced energy let-through mode.

Abstract: A method and system for a power distribution system are provided. The method includes determining at a central controller normal mode configuration settings for a plurality of circuit breakers of the power distribution system and determining at the central controller alternate mode configuration settings for the plurality of circuit breakers of the power distribution system. The method further includes controlling with the central controller the operation of the plurality of circuit breakers based on the normal mode configuration settings and the alternate mode configuration settings.

Abstract: A circuit protection system is provided that provides simultaneous bus differential and transformer differential protection for a power distribution system. The circuit protection system can obviate the need for a circuit breaker disposed between the transformer and the power bus due to the un-delayed tripping of the upstream circuit breaker. The circuit protection system can also provide multiple layers of protection both upstream and downstream of the transformer and the power bus.

Abstract: There is provided a method of controlling circuit breakers in a multi-phase power system. The method includes (a) recognizing a concurrent presence of a first fault in a first phase of the power system and a second fault in a second phase of the power system, where the power system includes a first circuit breaker situated to conduct a fault current between the first and second phases; and (b) controlling a second circuit breaker to open so that the fault current is interrupted, where the second circuit breaker, when closed, provides current to the first circuit breaker.

Abstract: A method for locating a ground fault in an electrical power distribution system includes providing a plurality of current sensors at a plurality of locations in the electrical power distribution system. The method further includes detecting a ground fault in the electrical power distribution system. Current is monitored at a plurality of locations in the electrical power distribution system via the current sensors and a test signal is introduced into the electrical power distribution system via a test signal generating device. The plurality of locations are monitored to locate the ground fault between a location at which the test signal is detected and a downstream location at which the test signal is not detected.