This present application concerns a method for preventing an electrical grid from a failure in case of a temporary overvoltage. A method comprising: a) providing an electrical grid line, a surge arrester and a disconnector device with a disconnector unit; b) connecting the surge arrester at one terminal to the electrical grid line; c) connecting the surge arrester at its other terminal to a second terminal of the disconnector device; d) connecting a first terminal of the disconnector device to ground potential; e) interrupting the electrical connection in between the electrical grid line and the ground potential in case of a temporary overvoltage; f) protecting the surge arrester from failure due to a thermal overload caused by the temporary overvoltages by operating the disconnector device before the surge arrester fails due to a thermal overload of the surge arrester.

A crowbar device has a first terminal and a second terminal, the terminals being connectible to a medium to high impedance AC voltage source including a trigger circuit configured to output a trigger signal responsive to exceeding a threshold voltage across at least one trigger element of the trigger circuit; a positive-side signaling circuit and a negative-side signaling circuit configured to output a positive or a negative clamping signal, respectively, according to a positive-voltage or a negative-voltage signal, respectively, input from the trigger circuit; and a positive-side overvoltage clamping circuit and a negative-side overvoltage clamping circuit configured to control their respective semiconductor element to be in a conducting state, when the clamping signal from the corresponding signaling circuit is present, and configured to control their semiconductor element to be in a non-conducting state, when the corresponding clamping signal has not been present for a predetermined time period.

A crowbar device has a first terminal and a second terminal, the terminals being connectible to a medium to high impedance AC voltage source including a trigger circuit configured to output a trigger signal responsive to exceeding a threshold voltage across at least one trigger element of the trigger circuit; a positive-side signaling circuit and a negative-side signaling circuit configured to output a positive or a negative clamping signal, respectively, according to a positive-voltage or a negative-voltage signal, respectively, input from the trigger circuit; and a positive-side overvoltage clamping circuit and a negative-side overvoltage clamping circuit configured to control their respective semiconductor element to be in a conducting state, when the clamping signal from the corresponding signaling circuit is present, and configured to control their semiconductor element to be in a non-conducting state, when the corresponding clamping signal has not been present for a predetermined time period.

An externally gapped line arrester, EGLA, for transmission lines, the EGLA including a series varistor unit, SVU, having a first end and a second end, the SVU configured to be connected between a transmission line and ground, a primary sparkover gap unit serially connected to the first end of the SVU, a secondary gap arranged between the second end of the SVU and ground, and the secondary gap serially connected to the second end of the SVU, a shorting-link device connected in parallel with the secondary gap, and a disconnecting device arranged in the shorting-link device, the disconnecting device configured to open the shorting-link device when the SVU is overloaded. A method for impulse protection performed by an EGLA is also disclosed.

An externally gapped line arrester, EGLA, for transmission lines, the EGLA including a series varistor unit, SVU, having a first end and a second end, the SVU configured to be connected between a transmission line and ground, a primary sparkover gap unit serially connected to the first end of the SVU, a secondary gap arranged between the second end of the SVU and ground, and the secondary gap serially connected to the second end of the SVU, a shorting-link device connected in parallel with the secondary gap, and a disconnecting device arranged in the shorting-link device, the disconnecting device configured to open the shorting-link device when the SVU is overloaded. A method for impulse protection performed by an EGLA is also disclosed.

The present disclosure provides a circuit including a coaxial cable interface, a data module, a power module, a power signal transmission branch, and a data signal transmission branch. The data module may receive or output a data signal. The power module may receive or output a power signal. The power signal transmission branch may be electrically coupled between the coaxial cable interface and the power module, and may include an inductor that allows the power signal to pass. The data signal transmission branch may be electrically coupled between the coaxial cable interface and the data module, and may include a capacitor that allows the data signal to pass and a first electrical surge protection circuit. The first electrical surge protection circuit may release a surge current on the data signal transmission branch.

An apparatus includes a surge protection device, a current sensor configured to sense a current through the surge protection device, and a surge discriminator circuit coupled to the current sensor and configured to discriminate among a plurality of surge levels for the surge protective device responsive to the sensed current. The current sensor may include a current transformer configured to generate a secondary current responsive to the sensed current and the surge discriminator circuit may be configured to discriminate among a plurality of surge levels responsive to the generated secondary current.

An apparatus includes a housing (e.g., a housing having a form factor of a molded case circuit breaker) and at least two phase terminals supported by the housing and configured to be connected to respective ones of at least two phase buses in an electrical panelboard. The apparatus further includes at least one fault generation device supported by the housing and including an arc containment chamber and first and second spaced-apart electrodes in the arc containment chamber and electrically coupled to respective ones of the at least two phase terminals.

An apparatus includes a housing (e.g., a housing having a form factor of a molded case circuit breaker) and at least two phase terminals supported by the housing and configured to be connected to respective ones of at least two phase buses in an electrical panelboard. The apparatus further includes at least one fault generation device supported by the housing and including an arc containment chamber and first and second spaced-apart electrodes in the arc containment chamber and electrically coupled to respective ones of the at least two phase terminals.

The present disclosure provides a circuit including a coaxial cable interface, a data module, a power module, a power signal transmission branch, and a data signal transmission branch. The data module may receive or output a data signal. The power module may receive or output a power signal. The power signal transmission branch may be electrically coupled between the coaxial cable interface and the power module, and may include an inductor that allows the power signal to pass. The data signal transmission branch may be electrically coupled between the coaxial cable interface and the data module, and may include a capacitor that allows the data signal to pass and a first electrical surge protection circuit. The first electrical surge protection circuit may release a surge current on the data signal transmission branch.