The present disclosure relates to a monitoring assembly for monitoring a supply signal of an electrically operated component, wherein the monitoring assembly comprises a monitoring circuit and a control and evaluation unit assigned to the monitoring circuit. At least one galvanically isolated connection is provided between the monitoring circuit and the control and evaluation unit. The monitoring circuit includes at least one threshold-dependent component which generates a current signal as a function of an applied supply voltage. The supply voltage is an AC voltage. The at least one threshold-dependent component is configured so as to generate a current signal when the supply voltage is above a first threshold value. The control and evaluation unit is set up to evaluate the at least one transmitted output signal to determine a fault condition. The control and evaluation unit is set up to output a drive signal when the fault condition has been determined. A system is furthermore described.

The present disclosure relates to a monitoring assembly for monitoring a supply signal of an electrically operated component, wherein the monitoring assembly comprises a monitoring circuit and a control and evaluation unit assigned to the monitoring circuit. At least one galvanically isolated connection is provided between the monitoring circuit and the control and evaluation unit. The monitoring circuit includes at least one threshold-dependent component which generates a current signal as a function of an applied supply voltage. The supply voltage is an AC voltage. The at least one threshold-dependent component is configured so as to generate a current signal when the supply voltage is above a first threshold value. The control and evaluation unit is set up to evaluate the at least one transmitted output signal to determine a fault condition. The control and evaluation unit is set up to output a drive signal when the fault condition has been determined. A system is furthermore described.

The present disclosure relates to provide an active erroneous sample elimination device or erroneous sample elimination method for a relay capable of correctly implementing erroneous sample elimination processing even during a plurality of electrical disturbances mixed with an electrical quantity detection signal, and a digital protective relay according to the present disclosure may include a converter that samples an analog signal and converts the sampled signal to a digital signal; and a processor that searches an inflection point at which an electrical variation quantity varies from an increase to a decrease or from a decrease to an increase based on the digital signal, and compares an electrical variation quantity prior to and subsequent to the inflection point with a preset electrical quantity.

The present disclosure relates to provide an active erroneous sample elimination device or erroneous sample elimination method for a relay capable of correctly implementing erroneous sample elimination processing even during a plurality of electrical disturbances mixed with an electrical quantity detection signal, and a digital protective relay according to the present disclosure may include a converter that samples an analog signal and converts the sampled signal to a digital signal; and a processor that searches an inflection point at which an electrical variation quantity varies from an increase to a decrease or from a decrease to an increase based on the digital signal, and compares an electrical variation quantity prior to and subsequent to the inflection point with a preset electrical quantity.

In aspects of the present disclosure, a circuit interrupter includes a housing, a conductive path, a switch which selectively interrupts the conductive path, sensor(s), memory, and a controller within the housing. The sensor(s) measure electrical characteristic(s) of the conductive path. The memory stores an arc detection program that implements a machine learning model and includes a field-updatable program portion and a non-field-updatable program portion, where the field-updatable program portion includes program parameters used by the non-field-updatable program portion to decide between presence or absence of an arc fault. The controller executes the arc detection program to compute input data for the machine learning model based on the sensor measurements, decide between presence of an arc event or absence of an arc event based on the input data, and cause the switch to interrupt the conductive path when the decision indicates presence of an arc event.

An arc fault detection system includes a first current sensor, a second current sensor, a band-pass filter, and a comparator module. The first current sensor, the second current sensor, and the comparator module are each connected to the comparator module by direct leads for biasing a current differential between the first current sensor and the second current sensor using a bias calculated from a frequency component indicative of arc events received from the frequency selector.

An apparatus is for a power circuit providing an alternating current to a load. The apparatus includes a high frequency current sensor structured to cooperate with the power circuit to provide a high frequency current signal. A voltage zero crossing detector is structured to cooperate with the power circuit to provide a voltage zero crossing signal. A high pass filter is structured to provide a filtered current signal from the high frequency current signal. A threshold comparator is structured to provide an output when the filtered current signal exceeds a predetermined value. A processor is structured to receive the voltage zero crossing signal and the output of the threshold comparator and output a trip signal in response to undesired series arcing by detecting an unsymmetrical high frequency signal for a predetermined number of cycles.

A method detects faults during a steady state of an operation of an induction motor. The method measures, in a time domain, a signal of a current powering the induction motor with a fundamental frequency and determines, in a frequency domain, a set of frequencies with non-zero amplitudes, such that a reconstructed signal formed by the set of frequencies with non-zero amplitudes approximates the signal measured in the time domain. The determining includes a compressive sensing via searching within a subband including the fundamental frequency of the signal subject to condition of a sparsity of the signal in the frequency domain. The method detects a fault in the induction motor if the set of frequencies includes a fault frequency different from the fundamental frequency.

A method detects faults during a steady state of an operation of an induction motor. The method measures, in a time domain, a signal of a current powering the induction motor with a fundamental frequency and determines, in a frequency domain, a set of frequencies with non-zero amplitudes, such that a reconstructed signal formed by the set of frequencies with non-zero amplitudes approximates the signal measured in the time domain. The determining includes a compressive sensing via searching within a subband including the fundamental frequency of the signal subject to condition of a sparsity of the signal in the frequency domain. The method detects a fault in the induction motor if the set of frequencies includes a fault frequency different from the fundamental frequency.

A protection circuit may be electrically connected to a transformer neutral of a power grid transformer. The protection circuit may include a direct current (DC) blocking component electrically connected between the transformer neutral and a ground connection, as well as a direct current switch assembly positioned in parallel with the direct current blocking component between the transformer neutral and the ground connection. The direct current switch assembly includes at least one direct current switch having a switching element that is electrically controllable between a closed position and an open position. In some examples, a conductive housing encloses one or more switching elements. The conductive housing is electrically isolated from the ground connection. In further examples, one or more direct current switches may be electrically connected in series to provide greater voltage withstand and safety due to operational redundancy.