Abstract: An example method of operating a solidly grounded, multi-source, multi-phase power distribution system having coupled neutral conductors is disclosed. The power distribution system includes a bus, a plurality of source protection devices coupled to the bus, and a plurality of feeder protection devices coupled to the bus. The method includes receiving, for each source protection device of the plurality of source protection devices, data indicative of detected source phase currents associated with the source protection device. Data indicative of detected feeder neutral currents and detected feeder phase currents associated with the feeder protection device are received for each feeder protection device of the plurality of feeder protection devices. A net source ground fault current associated with the plurality of source protection devices is determined based on the received data indicative of source phase currents and the received data indicative of feeder neutral currents and feeder phase currents.

Abstract: An example method of operating a solidly grounded, multi-source, multi-phase power distribution system having coupled neutral conductors is disclosed. The power distribution system includes a bus, a plurality of source protection devices coupled to the bus, and a plurality of feeder protection devices coupled to the bus. The method includes receiving, for each source protection device of the plurality of source protection devices, data indicative of detected source phase currents associated with the source protection device. Data indicative of detected feeder neutral currents and detected feeder phase currents associated with the feeder protection device are received for each feeder protection device of the plurality of feeder protection devices. A net source ground fault current associated with the plurality of source protection devices is determined based on the received data indicative of source phase currents and the received data indicative of feeder neutral currents and feeder phase currents.

Abstract: Methods and systems for monitoring devices in a power distribution system are described. In one example, a method for use in a power distribution system including a plurality of devices is described. The method includes receiving a plurality of data signals associated with the power distribution system, determining a measurement error value associated with the power distribution system based on the plurality of data signals, comparing the determined measurement error value to a dynamic threshold, and generating an alert when the determined measurement error value exceeds the dynamic threshold.

Abstract: An example method of operating a power distribution system including a plurality of source and tie circuit protection devices coupled between at least one source and a protection zone is disclosed. The protection zone includes a distribution bus and a plurality of feeder circuit protection devices coupled between the distribution bus and a plurality of loads. The method includes determining an electric current flowing through each source and tie circuit protection device, determining whether any of the feeder circuit protection devices is outputting a ZSI blocking signal, and controlling operation of the plurality of source and tie circuit protection devices according to an enhanced partial differential protection scheme based on a combination of the determined currents through the source and tie circuit protection devices and the determination of whether any of the feeder circuit protection devices is outputting a ZSI blocking signal.

Abstract: Circuit protection devices, power distribution systems, and methods of monitoring circuit protection devices are described. In one example, a method of monitoring a circuit protection device in a zone selective interlocking (ZSI) system includes monitoring a variable associated with operation of the circuit protection device, determining, based at least in part on the monitored variable, when a likelihood of a malfunction of the circuit protection device exceeds a predetermined threshold, and preventing the circuit protection device from outputting a ZSI blocking signal when the likelihood of the malfunction of the circuit protection device exceeds the threshold.

Abstract: Power distribution systems and methods are described. In one example, a method of determining by a first circuit protection device in a zone selective interlocking (ZSI) system whether to output a blocking signal to a second circuit protection device in the ZSI system is described. The method includes detecting, by a current rate of change sensor, a rate of change of a current flowing through the first circuit protection device. A trip unit receives a current rate of change signal from the current rate of change sensor. The current rate of change signal is proportional to the detected rate of change of the current flowing through the first circuit protection device. The trip unit determines whether to output the blocking signal to the second circuit protection device based, at least in part, on the current rate of change signal.

Abstract: An apparatus is provided. The apparatus includes a plasma generation element physically coupled to a first main electrode. The plasma generation element includes at least a first open end and a second open end. Each open end defines a nozzle such that the first open end directs an ablative plasma to a second main electrode and the second open end directs the ablative plasma to a third main electrode.

Abstract: Circuit protection devices, power distribution systems, and circuit protection device monitoring in a zone selective interlocking (ZSI) system are described. In one example, a circuit protection device for use in a ZSI power distribution system includes a trip mechanism configured to interrupt current flowing through the circuit protection device, and a trip unit operatively coupled to the trip mechanism. The trip unit is configured to monitor current flowing through the circuit protection device, output a first signal when the monitored current is less than a threshold value, and output a second signal when the monitored current is greater than or equal to the threshold value. The first and second signals are different from each other and different than an absence of a signal.

Abstract: Methods, devices, and systems for automated maintenance mode switching are described. An example method of controlling a protection assembly mode of operation is described for use in a system having a protection assembly configured to receive power from an upstream power source and provide power and protection to a downstream protection device moveable between a fully engaged position and a fully disengaged position. The method includes determining, by the protection assembly, when a maintenance action is being performed on the downstream protection device, and switching the protection assembly from a normal protection mode to a maintenance mode of operation in response to determining the maintenance action is being performed on the downstream protection device.

Abstract: An example method of operating a power distribution system including a plurality of source and tie circuit protection devices coupled between at least one source and a protection zone is disclosed. The protection zone includes a distribution bus and a plurality of feeder circuit protection devices coupled between the distribution bus and a plurality of loads. The method includes determining an electric current flowing through each source and tie circuit protection device, determining whether any of the feeder circuit protection devices is outputting a ZSI blocking signal, and controlling operation of the plurality of source and tie circuit protection devices according to an enhanced partial differential protection scheme based on a combination of the determined currents through the source and tie circuit protection devices and the determination of whether any of the feeder circuit protection devices is outputting a ZSI blocking signal.

Abstract: Circuit protection devices, power distribution systems, and circuit protection device monitoring in a zone selective interlocking (ZSI) system are described. In one example, a circuit protection device for use in a ZSI power distribution system includes a trip mechanism configured to interrupt current flowing through the circuit protection device, and a trip unit operatively coupled to the trip mechanism. The trip unit is configured to monitor current flowing through the circuit protection device, output a first signal when the monitored current is less than a threshold value, and output a second signal when the monitored current is greater than or equal to the threshold value. The first and second signals are different from each other and different than an absence of a signal.

Abstract: Circuit protection devices, power distribution systems, and methods of monitoring circuit protection devices are described. In one example, a method of monitoring a circuit protection device in a zone selective interlocking (ZSI) system includes monitoring a variable associated with operation of the circuit protection device, determining, based at least in part on the monitored variable, when a likelihood of a malfunction of the circuit protection device exceeds a predetermined threshold, and preventing the circuit protection device from outputting a ZSI blocking signal when the likelihood of the malfunction of the circuit protection device exceeds the threshold.

Abstract: A power equipment protection system is provided. The power equipment protection system includes a first trip unit configured to monitor a first circuit, a second trip unit configured to monitor a second circuit that is downstream from the first circuit, an arc-flash (AF) sensor configured to detect an arc flash, an AF mitigation device, at least one current sensor, and a controller. The power equipment protection system is operable in a first mode and a second mode, wherein in the first mode, the controller is configured to activate the AF mitigation device based on signals generated by both the AF sensor and the at least one current sensor, and wherein in the second mode, the controller is configured to activate the AF mitigation device based on signals generated by at least one of the at least one current sensor and the AF sensor.

Abstract: A power equipment protection system is provided. The power equipment protection system includes a first trip unit configured to monitor a first circuit, a second trip unit configured to monitor a second circuit that is downstream from the first circuit, an arc-flash (AF) sensor configured to detect an arc flash, an AF mitigation device, at least one current sensor, and a controller. The power equipment protection system is operable in a first mode and a second mode, wherein in the first mode, the controller is configured to activate the AF mitigation device based on signals generated by both the AF sensor and the at least one current sensor, and wherein in the second mode, the controller is configured to activate the AF mitigation device based on signals generated by at least one of the at least one current sensor and the AF sensor.

Abstract: A control module coupled to a switching device that is switchable between an open state and a closed state as part of a switching event is provided. The control module includes a communication interface configured to issue a control signal to the switching device that triggers the switching device to switch between the open state and the closed state, and receive a feedback signal from the switching device indicating that the switching device has switched between the open state and the closed state. The control module further includes a processing device coupled to the communication interface and configured to calculate a characteristic time interval associated with the switching event, wherein the characteristic time interval is indicative of a mechanical switching time of the switching device, and a memory device coupled to the processing device and configured to store the calculated characteristic time interval.

Abstract: Power distribution systems and methods are described. In one example, a method of determining by a first circuit protection device in a zone selective interlocking (ZSI) system whether to output a blocking signal to a second circuit protection device in the ZSI system is described. The method includes detecting, by a current rate of change sensor, a rate of change of a current flowing through the first circuit protection device. A trip unit receives a current rate of change signal from the current rate of change sensor. The current rate of change signal is proportional to the detected rate of change of the current flowing through the first circuit protection device. The trip unit determines whether to output the blocking signal to the second circuit protection device based, at least in part, on the current rate of change signal.

Abstract: Methods and systems for monitoring devices in a power distribution system are described. In one example, a method for use in a power distribution system including a plurality of devices is described. The method includes receiving a plurality of data signals associated with the power distribution system, determining a measurement error value associated with the power distribution system based on the plurality of data signals, comparing the determined measurement error value to a dynamic threshold, and generating an alert when the determined measurement error value exceeds the dynamic threshold.

Abstract: A control module coupled to a switching device that is switchable between an open state and a closed state as part of a switching event is provided. The control module includes a communication interface configured to issue a control signal to the switching device that triggers the switching device to switch between the open state and the closed state, and receive a feedback signal from the switching device indicating that the switching device has switched between the open state and the closed state. The control module further includes a processing device coupled to the communication interface and configured to calculate a characteristic time interval associated with the switching event, wherein the characteristic time interval is indicative of a mechanical switching time of the switching device, and a memory device coupled to the processing device and configured to store the calculated characteristic time interval.

Abstract: An apparatus is provided. The apparatus includes a plasma generation element physically coupled to a first main electrode. The plasma generation element includes at least a first open end and a second open end. Each open end defines a nozzle such that the first open end directs an ablative plasma to a second main electrode and the second open end directs the ablative plasma to a third main electrode.

Abstract: An arc flash relay system is described for use in a power distribution system including an arc flash sensor, a first circuit protection device, and a second circuit protection device. The arc flash relay system includes a first input configured to receive a detection signal from the arc flash sensor, a second input configured to receive a blocking signal from the first circuit protection device, and a controller. The controller is configured to determine that an arc flash has occurred based, at least in part, on the detection signal. The controller activates the second circuit protection device in response to the determination that an arc flash has occurred when the controller is not receiving the blocking signal, and delays activation of the second circuit protection device in response to the determination that an arc flash has occurred when the controller is receiving the blocking signal.