In an embodiment, an arc light sensor includes: a first polarizer, a second polarizer, a magneto-optical material, a first light filter and a processing unit. The first polarizer is used for polarizing incident first target light, to form first polarized light in a first polarization direction. The second polarizer is used for polarizing incident second target light, to form second polarized light in the first polarization direction. The magneto-optical material, in a current magnetic field, uses the current magnetic field to rotate a polarization direction of the first polarized light, to form third polarized light. The first light filter is used for filtering the third polarized light, to form fourth polarized light capable of passing in a second polarization direction. The processing unit is used for determining whether the second target light is arc light according to intensity of the second polarized light and intensity of the fourth polarized light.

In an embodiment, an arc light sensor includes: a first polarizer, a second polarizer, a magneto-optical material, a first light filter and a processing unit. The first polarizer is used for polarizing incident first target light, to form first polarized light in a first polarization direction. The second polarizer is used for polarizing incident second target light, to form second polarized light in the first polarization direction. The magneto-optical material, in a current magnetic field, uses the current magnetic field to rotate a polarization direction of the first polarized light, to form third polarized light. The first light filter is used for filtering the third polarized light, to form fourth polarized light capable of passing in a second polarization direction. The processing unit is used for determining whether the second target light is arc light according to intensity of the second polarized light and intensity of the fourth polarized light.

An electric system has an electrical energy source connected to an electrical energy sink by at least one feeding line. Each feeding line (8) is in at least one position therealong between said source and said sink provided with an arrangement configured to interrupt arcing in the feeding line would such arcing reach this position. The arrangement has a temperature dependent member which upon an increase of the temperature thereof above a predetermined level activates an irreversible movement of movable means (24) which by this movement cuts off the arc (a) and/or removes hot ionized gases (28) and by that prevents the arcing to continue in the feeding line past the arrangement.

Systems and methods for improving control of an internal arc fault in equipment. The equipment includes a bus configured to provide three-phase power from an incoming line. Furthermore, the equipment includes a current loop formed from a first conductor and a second conductor, where current is received from the bus. The current loop uses electromagnetic forces of a short-circuit current caused by an internal arcing fault of the equipment to move the first and second conductors relative to each other. In response to the movement of the first and second conductors, the current loop creates a gap between the first and second conductors where a new arc ignites at the gap. In this manner, the loop design takes advantage of the natural electromagnetic force to reduce the arc energy at the point of initiation and relocates the energy release point to an exhaust vent of the equipment.

Systems and methods for improving control of an internal arc fault in equipment. The equipment includes a bus configured to provide three-phase power from an incoming line. Furthermore, the equipment includes a current loop formed from a first conductor and a second conductor, where current is received from the bus. The current loop uses electromagnetic forces of a short-circuit current caused by an internal arcing fault of the equipment to move the first and second conductors relative to each other. In response to the movement of the first and second conductors, the current loop creates a gap between the first and second conductors where a new arc ignites at the gap. In this manner, the loop design takes advantage of the natural electromagnetic force to reduce the arc energy at the point of initiation and relocates the energy release point to an exhaust vent of the equipment.

A switching device for an electric circuit, the switching device comprising: at least one phase having a movable contact which can be coupled to/separated from a corresponding fixed contact; a kinematic chain operatively associated to the movable contact; driving means adapted to move the kinematic chain between a first position and a second position for actuating the movable contact; and control means adapted to control the driving means. The kinematic chain is adapted to reach the second position from the first position before reaching a dead-point position, and the control means are adapted to: detect a loss condition of a power supply associable to and suitable for operating the switching device, while the kinematic chain is in the second position; and control the driving means to move the kinematic chain away from the second position when the loss condition is detected, in such a way that the kinematic chain passes through the dead-point position and reaches a third position between the dead-point position and corresponding blocking means of the switching device.

A sensor system for determining physical variables of a switchgear assembly having a sensor connection, which is designed for connection to the switchgear assembly, within which a humidity sensor and/or a pressure sensor and a light sensor for detecting light flashes are arranged. A switchgear assembly is provided that is filled, in particular, with a protective gas, comprising at least one such sensor system.

A sensor system for determining physical variables of a switchgear assembly having a sensor connection, which is designed for connection to the switchgear assembly, within which a humidity sensor and/or a pressure sensor and a light sensor for detecting light flashes are arranged. A switchgear assembly is provided that is filled, in particular, with a protective gas, comprising at least one such sensor system.

A device for monitoring partial discharges in an AC electrical network, the monitoring device being mounted in a switching apparatus provided with a vacuum bottle connected to one phase of the AC network. The monitoring device includes a partial discharge detector positioned facing the vacuum bottle and an electronic processing unit receiving a first signal representative of the partial discharges detected by the capacitive sensor and receiving a second signal representative of the voltage of the electrical network. The processing unit includes discriminating means which are capable, according to the first signal and the second signal, of determining whether the partial discharges originate from a loss of vacuum in the vacuum bottle or originate from another cause external to the vacuum bottle.

A method and a circuit for detecting an electric arc in an electric circuit supplied with AC current during a supply period includes measuring at least one input signal (S) among a current (I) and an input voltage (U) of the electric circuit, supplying a warning signal (A1) to indicate that an electric arc occurs when the input signal (S) is constant over at least one portion of the supply period, digitally sampling the input signal (S) during the measurement thereof according to predetermined levels and, to identify that the input signal (S) is constant, determining the frequency at which each level is reached by the input signal (S) over a predetermined time window, comparing the frequency of each level with a predetermined warning threshold, and issuing the warning signal if the frequency of at least one of the levels is higher than the warning threshold.