Disclosed is an electrical condition monitoring system that is connectable to an electrical device for monitoring the electrical device when in operation, wherein: (i) the electrical condition monitoring system includes (a) a sensing arrangement for temporally sensing an electrical supply to and/or from the electrical device and generating corresponding sensed data; (b) a data processing arrangement that is configured to process the sensed data to generate a corresponding temporally-changing Fourier spectrum including signal harmonic components and to process temporal changes in magnitudes and frequencies of the signal harmonic components to generate analysis data; and (ii) a user interface is configured for user entry of input for analyzing the analysis data and the data processing arrangement is configured to analyze the analysis data based on the input to obtain information indicative of operating condition of the electrical device; characterized in that: (iii) the data processing arrangement is operable to: identify at least one local maximum corresponding to a phenomenon on the temporally-changing Fourier spectrum; calculate locations on the temporally-changing Fourier spectrum where the same phenomenon appears to create a family of possible local maxima; identify a significant local maximum from the family of possible local maxima corresponding to the phenomenon and generate the analysis data from a magnitude of the significant local maximum; generate a real-time model of the electrical device based on the analysis data; and compare the real-time model with one or more stored models to generate information indicative of operating condition of the electrical device.

A DER (distributed energy resource) device includes a metrology module and a communications module. The metrology module monitors the output of the DER device and the communications module provides bidirectional communications across a communications network to control the DER device. The control of the DER devices may include commands to connect the DER device to the grid, to disconnect the DER device to the grid, to connect the DER device to the premises, or to adjust a power characteristic of the output of the DER device.

A DER (distributed energy resource) device includes a metrology module and a communications module. The metrology module monitors the output of the DER device and the communications module provides bidirectional communications across a communications network to control the DER device. The control of the DER devices may include commands to connect the DER device to the grid, to disconnect the DER device to the grid, to connect the DER device to the premises, or to adjust a power characteristic of the output of the DER device.

Effective feature set-based high impedance fault (HIF) detection is provided. Systems, methods and devices described herein present a systematic design of power feature extraction for HIF detection and classification. For example, power features associated with HIF events are extracted according to when a fault happens, how long it lasts, and the magnitude of the fault. Complementary power expert information is also integrated into feature pools. In another aspect, a ranking procedure is deployed in a feature pool for balancing information gain and complexity in order to avoid over-fitting of features. In aspects described herein, a logic-based HIF detector implements HIF feature extraction. To determine when an HIF occurs, the HIF detector calculates different quantities, such as active power and reactive power, based on a voltage and current time series, and uses the derivative of these quantities to tell when there is a potential change due to HIF.

The invention relates to a detection device (100) for detecting an arc (104a-i; 909) occurring between a first current-carrying element (103; 903a) and at least one conductive element (103b, 108; 903b, 907), comprising at least one measuring device (101; 901, 902), which is designed to measure a current (I) flowing through the first current-carrying element (103a; 903a), and an analysis device (102) which is designed to determine a frequency spectrum of the measured current (I) and to detect the arc (104a-i; 909) occurring between the first current-carrying element (103a; 903a) and the at least one conductive element (103b, 108; 903b, 907) on the basis of a high-frequency range of the determined frequency spectrum.

An earth leakage circuit breaker includes a current sensing unit configured to sense current in a circuit, a converter configured to detect a fundamental wave component and a specific harmonic component from the sensed current, the specific harmonic component being one of a plurality of harmonic components, and a controller. The controller is configured to compare a harmonic component ratio with a threshold component ratio, to determine whether the sensed current is abnormal current, and to control cutoff of the circuit according to the result of determination. The harmonic component ratio is a ratio of the specific harmonic component to the fundamental wave component. The converter is configured to convert the sensed current from an analog signal into digital data and to perform Fourier transform with respect to the converted digital data to detect the fundamental wave component and the specific harmonic component.

An earth leakage circuit breaker includes a current sensing unit configured to sense current in a circuit, a converter configured to detect a fundamental wave component and a specific harmonic component from the sensed current, the specific harmonic component being one of a plurality of harmonic components, and a controller. The controller is configured to compare a harmonic component ratio with a threshold component ratio, to determine whether the sensed current is abnormal current, and to control cutoff of the circuit according to the result of determination. The harmonic component ratio is a ratio of the specific harmonic component to the fundamental wave component. The converter is configured to convert the sensed current from an analog signal into digital data and to perform Fourier transform with respect to the converted digital data to detect the fundamental wave component and the specific harmonic component.

An abnormality diagnosis device includes: a data acquirer to acquire a current waveform and a driving frequency of an electric motor; a storage which stores a combination of a current value of the current waveform and the driving frequency at an identical time by the data acquirer; a data determiner to determine whether or not a current value of the current waveform and the driving frequency as a diagnosis target at an identical time by the data acquisition match the combination stored in the storage; an analyzer to perform frequency analysis for the current waveform determined to be matched by the data determiner, to extract sideband waves, and calculate a spectrum intensity of the sideband waves; and an abnormality diagnosis processor to make a diagnosis that abnormality has occurred, when the spectrum intensity of the sideband waves is equal to or greater than a threshold.

A conductor-mounted device (CMD) used to signal an intelligent electronic device (IED) of the existence of a fault on a portion of the electric power delivery system is described herein. The CMD may provide a heartbeat signal to the IED. The CMD may provide a fault signal to the IED. The CMD may be powered via a parasitic current draw on the conductor to which it is mounted. An IED may use a fault signal and/or LOC signal from a CMD to coordinate a high-impedance fault detection and/or downed line events.

A conductor-mounted device (CMD) used to signal an intelligent electronic device (IED) of the existence of a fault on a portion of the electric power delivery system is described herein. The CMD may provide a heartbeat signal to the IED. The CMD may provide a fault signal to the IED. The CMD may be powered via a parasitic current draw on the conductor to which it is mounted. An IED may use a fault signal and/or LOC signal from a CMD to coordinate a high-impedance fault detection and/or downed line events.