A method for protecting a power grid from an electrical fault, the electrical fault generating a first signal type and a second signal type, the power grid including an electrical power supply and an electrical device between which a contactor is arranged, the contactor being positionable in two states an open state, for which the electrical power supply is not electrically connected to the electrical device; a closed state, for which the electrical power supply is electrically connected to the electrical device; the method including detecting a signal of the first type; placing the contactor in the open state; verifying, during a predetermined time period, whether a signal of the second type appears; if a signal of the second type appears during the period, keeping the contactor in the open state; when no signal of the second type appears during the period, placing the contactor in the closed state.

A method locates an arc in a switchgear apparatus. The switchgear apparatus is subdivided into two or more detection zones, each detection zone is assigned at least one radiation sensor, the detection angle range of which covers the assigned detection zone. The radiation sensors sense the intensity of the radiation arriving from the associated detection angle range during the burning of the arc. On the basis of the sensed radiation intensities and the assignment between the radiation sensors and the detection zones, the detection zone in which the arc is located is determined.

Embodiments of the present disclosure may enable an electrical component within an electrical distribution equipment cabinet to be audibly monitored via an electrical fault detection device mounted on the housing of the cabinet. The electrical fault detection device may comprise a senor to detect a signal emitted from an electrical fault within the cabinet, a transducer to convert the detected signal into an electrical audio signal, and an output socket adapted for an external device that may generate an audible sound based on the detected signal. The detected sensor may be an ultrasound sensor and the detected signal may be an ultrasound emitted from the electrical fault.

An exemplary transformer protection system including a protective housing having a transformer which is arranged in the protective housing, a transformer core, and at least one primary-side electrical winding and a secondary-side electrical winding which is magnetically coupled to the primary-side electrical winding. The protection system also includes at least one detection apparatus for a measurement variable from which the occurrence of an interference arc within the protective housing can be derived, and an evaluation unit for generating a fault signal from the measurement variable of the at least one detection apparatus in the case of an interference arc. Further, the protection system includes at least one rapid-earthing apparatus for at least one of the electrical windings which is intended to be activated by the fault signal, wherein the rapid-earthing apparatus is designed in such a way that effective electrical earthing immediately after activation of the fault signal is ensured.

The invention relates to a device for detecting an electric arc based on an analog output signal (104) of at least one acoustic wave sensor (102), this device including: an analog-to-digital converter (106) capable of sampling and digitizing the output signal (104) of the sensor (102); a digital processing circuit (110) capable of implementing a frequency domain analysis of the digital output signal (108) of the converter (106) enabling to detect the possible presence of an arc based on its acoustic signature; and an analog circuit (118) for detecting the exceeding of a power threshold by the output signal (104) of the sensor (102), wherein the digital processing circuit (110) is configured to implement the frequency domain analysis only on detection of the exceeding of a threshold by the analog circuit (118).

An electrical metering system in a utility box is capable of receiving electrical signals received from a power utility company. The electrical metering system includes measurement circuitry capable of measuring properties of the received electrical signals. Based on the measurements, a determination is made that an arcing condition is present in the utility box. Based on the determination that the arcing condition is present, a disconnect circuit is activated to interrupt the connection between a source of the electrical signals and a premises.

A system including an arc flash sensor that detects an arc flash event and an arc flash mitigation device in communication with the sensor. The mitigation device includes a path of least resistance having a path input and a path output. The arc flash sensor is located downstream the output. The mitigation device includes an electro-mechanical switch between the input and the output and an actuator. The mitigation device also includes a bypass power switch device that includes a solid-state circuit interrupter and that conduct current between the input and the output in response to an open-circuit condition of the switch. A system controller is provided to generate a trigger to activate the actuator to generate the open-circuit condition of the switch, which causes the power switch device to interrupt a fault current associated with a fault event in response to detection of the arc flash event.

The disclosure relates to a method for detection of electrical abnormalities in association with electrical equipment. The method comprises registering, by an acoustic sensor device during a calibration process, acoustic signals reflecting sound of the electrical equipment during normal operation thereof, and determining an energy content threshold value (E.sub.th_A, E.sub.th_B) for acoustic signals within at least one frequency band (f.sub.A, f.sub.B) to be monitored during monitoring of the electrical equipment following the calibration process, based on the acoustic signals registered within the at least one frequency band during the calibration process. The method further comprises the steps of detecting, among acoustic signals registered by the acoustic sensor device during monitoring of the electrical equipment following the calibration process, an acoustic pulse (P) within the at least one frequency band (f.sub.A, f.sub.B), and classifying the acoustic pulse (P) as an electrical abnormality associated with the electrical equipment when an energy content of the acoustic pulse (P) exceeds the energy content threshold value (E.sub.th_A, E.sub.th_B). The disclosure further relates to a computer program and system for detection of electrical abnormalities in association with electrical equipment.

A method for fault protection of a terminal box of an electric rotating machine, and an arrangement including a terminal box for an electric rotating machine for electrically connecting the electric rotating machine to an electric system for transmitting electric power between the electric system and the electric rotating machine in one or more phases via the terminal box, a detection means configured to detect an electric arc inside the terminal box, and a switching means configured to electrically connect each of the one or more phases to earth in response to the detection means detecting the electric arc inside the terminal box or in response to the detection means detecting the electric arc inside the terminal box and one or more predetermined conditions being satisfied.

An arc detection assembly is provided and includes a first conductor comprising a first terminal end, a second conductor comprising a second terminal end, an enclosure to partially enclose a space in which the first and second terminal ends are engageable to form an electrical connection and an optical detection system. The optical detection system includes an optical element within the enclosure with a line-of-sight to an engagement of the first and second terminal ends and a sensor. The sensor is displaced from the enclosure and coupled to the optical element. The sensor is configured to determine when the optical element senses an arcing condition between the first and second terminal ends.