A method for detecting electric arcs in a closed chamber having no openings larger than 5 mm and defining a gas volume to be monitored. The method includes a step of measuring a sound level captured by a microphone, placed inside the chamber, at frequencies greater than about 60 kHz while filtering out the lower frequencies, and a step of comparing the level with a threshold.

A method for distinguishing an arc from a luminous gas at least containing metal vapor includes sensing light in a monitoring region and determining a first intensity I.sub.1 of the sensed light at a first wavelength 1 and a second intensity I.sub.2 of the sensed light at a second, greater wavelength 2. The ratio I.sub.1/I.sub.2 between the first intensity I.sub.1 and the second intensity I.sub.2 is determined. The sensed light is associated with an arc if said ratio I.sub.1/I.sub.2 is greater than a specifiable first threshold value and/or with a luminous gas at least containing metal vapor if said ratio I.sub.1/I.sub.2 is less than a specifiable second threshold value.

An electric system (100) includes a plurality of electric devices (110), each electric device (110) having a cabinet (112), a common power source (130), each electric device (110) being electrically coupled to the common power source (130), wherein a first electric device (110-1) includes an arc fault rated cabinet (112-1) and an arc quenching device (114), and wherein, in an event of an electric arc occurring in any of the plurality of electric devices (110), energy of the are is transferred to the first electric device (110-1) and the arc quenching device (114) activated.

Systems and techniques are disclosed that monitor an area adjacent to power system components and detect objects that may pose a probable risk of causing a fault, for example, making contact with the power system component. Various embodiments initiate a preventative, a corrective, and/or a mitigative action in advance of the fault. Examples of possible actions include, but are not limited to, an audible alert, a visual alert, a tactile alert, a remote notification, a limiting of machinery motion, a stopping of machinery motion, a reversing of machinery motion, de-energization of the power system component, or combinations thereof.

Devices and methods for arc fault detection, based on arc sound signals, are disclosed. The device can monitor sound data from a power device by one or more microphones arranged near the power device and extract the characteristic of the sound data. The device can also compare the characteristic of the sound data with the arc fault feature database, and then determine to generate an arc alarm signal. The device is a stand-alone device, which can provide the forecast and early warning of arc faults, and can improve the reliability of arc fault detection.

A voltage transient detector includes circuitry for transmitting electrical current through a light emitting diode and a fuse that is serially connected between the light emitting diode and a reference potential, such that the light emitting diode is illuminated when the fuse is not blown. The voltage transient detector also includes circuitry for transmitting a controlled amount of electrical current through the fuse in conjunction with an occurrence of a voltage transient at a voltage measurement location, where the voltage transient exceeds a set transient threshold voltage. The controlled amount of electrical current transmitted through the fuse causing the fuse to blow and the light emitting diode to turn off, thereby indicating occurrence of the voltage transient at the voltage measurement location.

The disclosure describes a system for monitoring and mitigating damage to electrical utility structures and the surrounding environment. In some embodiments, the system includes fire boxes, arc sensors, angle switches, and disconnect switches configured to generate alert signals when a hazard is detected. In some embodiments, the system includes cameras configured to detect a hazard such as a fire or moving object. In some embodiments, the system includes light transmitters and light receivers positioned at a predetermined location away from power lines to detect objects that interrupt a line of site. In some embodiments, the system can electrically isolate a power line before a detected hazard impacts a power line.

A fuse box that is designed to prevent damage caused by arc faults and electrical overcurrent. The apparatus is configured to function as a circuit breaker. The apparatus includes a housing, a circuit breaker, an optical sensor, and an electronic controller. The housing is an enclosure that isolates the circuit breaker from light and protects the components from physical damage. The circuit breaker opens the circuit between connected electrical systems when arc fault or an electrical overcurrent is detected. The optical sensor detects arc faults and relays notifications to the electronic controller. The electronic controller enables a user to set the thresholds for arc faults, currents, and voltages that cause the circuit breaker to open.

An electrical system includes first, second and third busses; a first interrupter electrically connected between the first and second busses; at least one of a shorting apparatus operatively associated with the first or second bus, and the first interrupter comprising a trip coil; a current sensor to sense a fault current flowing in the first bus and responsively output a first signal; a number of light sensors to sense an arc flash operatively associated with a number of the first, second or third busses and responsively output a second signal; a second interrupter electrically connected between the second and third power busses and output a third signal; and a circuit to invert the third signal to provide a fourth signal, and to operate the at least one of the shorting apparatus and the trip coil responsive to an AND of the first, second and fourth signals.

A method includes detecting any light beam from 300 nm to 430 nm within the distribution system and, when this beam is detected, generating a signal indicating the presence of an internal arc inside the system; analyzing the characteristics of the light beam based on the signal and, if these characteristics meet required conditions for characterizing an internal arc fault, sending an internal arc fault signal, then; in the presence of an internal arc fault, attenuating its effects in the distribution system. Between the detecting and the analyzing, the visible and infrared portions of this beam are removed, these portions being likely to arise from ionized gases ejected by outlets of a low-voltage circuit breaker interrupting a short-circuit current. A protection device for carrying out this method includes a light detector associated with current-measuring sensors, and protection means including a main circuit breaker, a short-circuiter and a relay.