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.

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.

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.

A method for isolating an electrical fault in a floating High Voltage direct current (DC) system is provided. The method includes receiving a measurement of an output voltage of a High Voltage DC bus and receiving a measurement of a load current for each of a plurality of channels coupled to the High Voltage DC bus. The method also includes, when the output voltage is determined to be out of balance, comparing the measurement of the load current of each of the plurality of channels in the frequency domain, and, flagging one channel of the plurality of channels as a faulty channel based on the comparing the measurement of the load currents in the frequency domain.

A detection scheme for temporary overvoltages and/or ground fault overvoltages in electric power systems is described. Current passing through a surge arrestor component of the power system is monitored. An algorithm for identifying one or more frequency components of the measured current signal is performed to screen out unwanted harmonics. In some embodiments, this is a frequency domain analysis. The frequency component(s) of the current signal is then compared to a calculated pickup current or pickup voltage of the system to determine if system protection steps should be undertaken.

A protection circuit is disclosed. The protection circuit includes a direct current (DC) blocking component electrically connected between a neutral of the transformer and a ground, and an overvoltage protection device electrically connected in parallel with the DC blocking component. The overvoltage protection device is constructed to repeatably and reliably provide overvoltage protection in response to a voltage at the transformer neutral above a threshold. The DC blocking component has an impedance below a predetermined value, thereby effectively grounding the neutral of the transformer. The DC blocking component is persistently maintained in connection to the transformer neutral.

Detection of electric power generator stator ground fault conditions and protection of the generator due to such conditions is provided herein. In one embodiment, a generator protection element may calculate generator third harmonic voltage quantities using measurements from the generator terminals, and determine a stator ground fault condition using the calculated generator third harmonic voltage quantity. A tripping subsystem may issue a trip command based upon detection of a stator ground fault condition.

Detection of electric power generator stator ground fault conditions and protection of the generator due to such conditions is provided herein. In one embodiment, a generator protection element may calculate generator third harmonic voltage quantities using measurements from the generator terminals, and determine a stator ground fault condition using the calculated generator third harmonic voltage quantity. A tripping subsystem may issue a trip command based upon detection of a stator ground fault condition.

A method and system are provided for transferring a load between a primary power source and a secondary power source. In accordance with the disclosure, a controller senses, via a sensor, an electrical signal providing power from the primary power source to the load. The controller also detects a non-conforming power event by determining that a parameter of the electrical signal is either more or less than a first threshold value. Responsive to the detection of the non-conforming power event, the controller determines a quantity of non-conforming power events that occur during a first time interval. The controller further can compares the determined quantity of non-conforming power events to a second threshold value. Responsive to the determined quantity of non-conforming power events being either greater or lesser than the second threshold value, the controller initiates a control signal, such as a control signal to initiate a load transfer.