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 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 method of monitoring an electrical system may include providing a ground fault detection unit, operating a transformer rectifier unit to provide DC power to a load, sensing, via a current sensor, a ground current at or about an output of the transformer rectifier, and/or monitoring a sensor output from the current sensor via the ground fault detection circuit. The ground fault detection circuit may be configured to detect ground faults at frequencies of at least 30 kHz.

A method and device for load shedding in an electrical power system is provided. The electrical power system includes a device that electrically couples one or more load feeder lines to the electrical power system, where each load feeder lines provides power to consumers. The method includes: monitoring the electrical frequency of the electrical power system and monitoring a frequency stability parameter, which is dependent on a rate of change of the electrical frequency. A control signal is generated to disconnect at least one load feeder line by the device when the monitored frequency is at or below at least a predetermined disconnection frequency threshold and the monitored frequency stability parameter is at or has passed at least one predetermined frequency stability parameter threshold.

A method and device for load shedding in an electrical power system is provided. The electrical power system includes a device that electrically couples one or more load feeder lines to the electrical power system, where each load feeder lines provides power to consumers. The method includes: monitoring the electrical frequency of the electrical power system and monitoring a frequency stability parameter, which is dependent on a rate of change of the electrical frequency. A control signal is generated to disconnect at least one load feeder line by the device when the monitored frequency is at or below at least a predetermined disconnection frequency threshold and the monitored frequency stability parameter is at or has passed at least one predetermined frequency stability parameter threshold.

A system includes a transformer rectifier unit (TRU) having three inputs, a first AC bus configured to supply power to a first of the three inputs, a second AC bus configured to supply power to a second of the three inputs, and a third AC bus configured to supply power to a third of the three inputs. The system includes a power quality sense device electrically connected to each of the first, second and third AC busses. The system includes an electrically held contactor electrically connected between the TRU and the power quality sense device. The electrically held contactor is configured and adapted to be switched ON or OFF depending on whether the power quality sense device is energized or de-energized.

A wiring device including one or more line terminals and a controller. The controller is configured to, determine a frequency of an input voltage at the one or more line terminals, determine whether the frequency is within a predetermined range, and when the frequency is within the predetermined range, perform a test of the wiring device.

A wiring device including one or more line terminals and a controller. The controller is configured to, determine a frequency of an input voltage at the one or more line terminals, determine whether the frequency is within a predetermined range, and when the frequency is within the predetermined range, perform a test of the wiring device.

A modular load management system comprises one or more compact modules designed to fit in the wiring troughs of a standard AC distribution panel of a building. The modules include one or more input terminals to receive electrical power from one or more circuit breakers in the panel and deliver power to load circuits of the building via one or more output terminals. The modules contain at least one disconnect switch for disconnecting circuits from breakers in response to a remote or locally-generated control signal. The modules may also include current sensors on some or all terminals, such that power and energy flow may be monitored on a per-circuit basis.

A wiring device including an interrupting device and a controller. The interrupting device electrically connects one or more line terminals to one or more load terminals when the interrupting device is in a reset condition and disconnects the line terminals from the load terminals when the interrupting device is in a tripped condition. The controller is configured to, determine a frequency of an input voltage at the one or more line terminals, determine whether the frequency is within a predetermined range, and when the frequency is within the predetermined range, perform a test of the wiring device.