In described examples, a first transistor has: a drain coupled to a source of a depletion-mode transistor; a source coupled to a first voltage node; and a gate coupled to a control node. A second transistor has: a drain coupled to a gate of the depletion-mode transistor; a source coupled to the first voltage node; and a gate coupled through at least one first logic device to an input node. A third transistor has: a drain coupled to the gate of the depletion-mode transistor; a source coupled to a second voltage node; and a gate coupled through at least one second logic device to the input node.

Technologies for detecting a fault location in a DC electrical distribution system include a bus protection unit that monitors a DC electrical bus. The bus protection unit includes at least one sensor to produce sensor data indicative of one or more characteristics of the DC electrical bus monitored by the bus protection unit. The bus protection unit monitors the sensor data, determines whether a fault has occurred based on the sensor data, and determines whether the fault occurred within a bus zone defined by the DC electrical bus in response to determining that the fault has occurred. Further, the bus detection unit trips isolation devices within the bus zone in response to a determination that the fault occurred within the bus zone or a communication from another bus protection unit indicating the fault has occurred within the bus zone. The bus protection unit transmits a bus fault indication signal to another bus protection unit in response to a determination that the fault has occurred.

In some examples, a device includes a memory configured to store a pre-warning threshold level for a parameter of a power switch. The device also includes a logic circuit configured to receive a signal from a controller and set the pre-warning threshold level in response to receiving the signal from the controller. The logic circuit is also configured to determine that a magnitude of the parameter of the power switch does not satisfy the pre-warning threshold level. The logic circuit is further configured to output an alert to the controller in response to determining that the magnitude of the parameter does not satisfy the pre-warning threshold level.

In some examples, a device includes a memory configured to store a pre-warning threshold level for a parameter of a power switch. The device also includes a logic circuit configured to receive a signal from a controller and set the pre-warning threshold level in response to receiving the signal from the controller. The logic circuit is also configured to determine that a magnitude of the parameter of the power switch does not satisfy the pre-warning threshold level. The logic circuit is further configured to output an alert to the controller in response to determining that the magnitude of the parameter does not satisfy the pre-warning threshold level.

A wiring device including an interrupting device, a fault detection circuit, and a testing circuit. The interrupting device is electrically connecting one or more line terminals to one or more load terminals. The fault detection circuit is configured to detect a fault condition and generate a fault detection signal in response to detecting the fault condition. The fault detection signal being provided to the interrupting device to place the interrupting device in a tripped condition. The testing circuit is configured to determine a frequency of an input voltage at the one or more line terminals, filter the frequency of the input voltage, determine whether the filtered frequency is within a predetermined range, and when the filtered frequency is within the predetermined range, perform a test of the wiring device.

A communications and processing module is provided. The communications and processing module is electrically coupleable to a circuit breaker to provide the circuit breaker with additional capabilities. The communications and processing module includes a housing, at least one electrical contact positioned in the housing, an output lug positioned in the housing, wherein an electrical path is defined between the at least one electrical contact and the output lug, at least one sensor positioned in the housing and operable to sense at least one operating condition of the circuit breaker, and at least one communications interface positioned in the housing and communicatively coupled to the at least one sensor, the communications interface operable to receive data from the at least one sensor that is indicative of the at least one sensed operating condition to facilitate exporting the received data to a remote computing device.

A method for quantifying power quality events in an electrical system including a plurality of intelligent electronic devices (IEDs) includes processing electrical measurement data from or derived from energy-related signals captured by at least one first IED of the plurality of IEDs to identify a power quality event at a first point of installation of the at least one first IED in the electrical system. An impact of the power quality event at a second point of installation in the electrical system is determined based on an evaluation of electrical measurement data from or derived from energy-related signals captured by at least one second IED of the plurality of IEDs at the second point of installation proximate to a determined time of occurrence of the power quality event at the first point of installation.

An apparatus for monitoring an electrical apparatus, the load monitoring apparatus comprising a controller which is configured to capture and process voltage and current data of an electrical apparatus, which is electrically connected with a power supply, to obtain electrical parameters of the electrical apparatus, to store the electrical parameters as measured electrical parameters, to compare the measured electrical parameters with a set of pre-stored electrical parameters, to determine whether the measured electrical parameters match with the stored electrical parameters, and to operate a power switch to turn off power supply to the electrical parameters if the measured electrical parameters do not match with the stored electrical parameters.

A method for analyzing power quality events in an electrical system includes processing electrical measurement data from or derived from energy-related signals captured by at least one metering device in the electrical system to generate at least one dynamic tolerance curve. Each dynamic tolerance curve of the at least one dynamic tolerance curve characterizes a response characteristic of the electrical system at a respective metering point in the electrical system. The method also includes analyzing the at least one dynamic tolerance curve to identify special cases which require further evaluation(s)/clarification to be discernable and/or actionable. The at least one dynamic tolerance curve may be regenerated or updated, and/or new or additional dynamic tolerance curves may be generated, to provide the further clarification. One or more actions affecting at least one component in the electrical system may be performed in response to an analysis of the curve(s).

An electronic device includes a monitoring unit that monitors a voltage of a first terminal that receives power supplied from a power supply apparatus, and a control unit that performs control so as to stop the power supply from the power supply apparatus if a voltage variation per unit time of the first terminal is not less than a first predetermined value or the voltage of the first terminal is not less than a second predetermined value.