An arrangement for an overvoltage protection of a subsea electrical apparatus and a method for operating it. The arrangement includes a tank submersible below a water surface level, an electrical apparatus accommodated in the tank, and a surge arrester arrangement accommodated in the tank and coupled to a power supply of the electrical apparatus in the tank for providing the overvoltage protection of the electrical apparatus. The arrangement further includes a controllable grounding switch for connecting the surge arrester arrangement to a ground point in response to a control of the grounding switch to a closed state and for disconnecting the surge arrester arrangement from the ground point in response to a control of the grounding switch to an open state.

An arrangement for an overvoltage protection of a subsea electrical apparatus and a method for operating it. The arrangement includes a tank submersible below a water surface level, an electrical apparatus accommodated in the tank, and a surge arrester arrangement accommodated in the tank and coupled to a power supply of the electrical apparatus in the tank for providing the overvoltage protection of the electrical apparatus. The arrangement further includes a controllable grounding switch for connecting the surge arrester arrangement to a ground point in response to a control of the grounding switch to a closed state and for disconnecting the surge arrester arrangement from the ground point in response to a control of the grounding switch to an open state.

A fuse case and a case cover of a vacuum contactor including a truck, a main circuit unit, and a front cover covering a front side of the main circuit unit include a fuse connected to an upper terminal of the main circuit unit and blowing, when a fault current is generated in a circuit, to break the circuit, a fuse case opened in an upper side, accommodating the fuse, and having an insertion coupling part formed on a side surface thereof, and a case cover coupled to an upper side of the fuse case, coupled to the insertion coupling part in an insertion coupling manner, and covering a rear end portion of the fuse, wherein the case cover includes an upper surface portion and side surface portions, and the side surface portions include a first side surface portion and a second side surface portion.

A shielding arrangement can be provided for a piece of high voltage equipment spaced from a neighboring object. The piece of high voltage equipment has a first electric potential and the neighboring object has a second electric potential. The shielding arrangement includes a resistor, a shield element for connection to the high voltage equipment via the resistor, and a capacitor connected in parallel with the resistor. A resistance of the resistor and a capacitance of the capacitor together define a time constant in a range of 10 μs-50 ms.

A shielding arrangement can be provided for a piece of high voltage equipment spaced from a neighboring object. The piece of high voltage equipment has a first electric potential and the neighboring object has a second electric potential. The shielding arrangement includes a resistor, a shield element for connection to the high voltage equipment via the resistor, and a capacitor connected in parallel with the resistor. A resistance of the resistor and a capacitance of the capacitor together define a time constant in a range of 10 μs-50 ms.

An arrangement for an overvoltage protection of a subsea electrical apparatus and a method for operating it. The arrangement includes a tank submersible below a water surface level, an electrical apparatus accommodated in the tank, and a surge arrester arrangement accommodated in the tank and coupled to a power supply of the electrical apparatus in the tank for providing the overvoltage protection of the electrical apparatus. The arrangement further includes a controllable grounding switch for connecting the surge arrester arrangement to a ground point in response to a control of the grounding switch to a closed state and for disconnecting the surge arrester arrangement from the ground point in response to a control of the grounding switch to an open state.

An arrangement for an overvoltage protection of a subsea electrical apparatus and a method for operating it. The arrangement includes a tank submersible below a water surface level, an electrical apparatus accommodated in the tank, and a surge arrester arrangement accommodated in the tank and coupled to a power supply of the electrical apparatus in the tank for providing the overvoltage protection of the electrical apparatus. The arrangement further includes a controllable grounding switch for connecting the surge arrester arrangement to a ground point in response to a control of the grounding switch to a closed state and for disconnecting the surge arrester arrangement from the ground point in response to a control of the grounding switch to an open state.

A compact auxiliary connector can include two bushings each with an electrical connector(s), and a tubing connected between the two bushings to insulate an electrical cable, which is connected between electrical connectors of the two bushings. The electrical connector of each of the two bushings can be connected to an electrical device, a line or load bus or a combination thereof, according to the desired connection configuration. Each bushing may also include a flexible joint cover, such as a boot, to cover the connection of the bushing connectors to a bus, such as a primary bus. The compact auxiliary connector can manage live connections between auxiliary or other device(s) and line/load buses in a switchgear cabinet of a switchgear assembly. The bushings, tubing and flexible joint cover can be formed of insulating materials having desired dielectric strength according to the voltage applications.

A medium-voltage switchgear system includes a three-phase circuit breaker having first, second and third single-phase vacuum interrupters connected between respective first, second and third single-phase inputs and first, second and third single-phase outputs. Magnetic actuators are connected to first, second and third single-phase vacuum interrupters, which are configured to receive an interrupt signal and in response, actuate the respective vacuum interrupter connected thereto into an open circuit condition. A controller circuit is connected to each of the first, second and third magnetic actuators and generates an interrupt signal in response to a detected single-phase overcurrent or fault on a single-phase circuit and interrupt that single-phase circuit on which the single-phase overcurrent or fault occurred and maintain power on the remaining two single-phase circuits over which a single-phase overcurrent or fault was not detected.

A switchgear system includes a switchgear frame having an interior compartment and front opening and containing therein at least one electrical switchgear component. A truck carries an electrical component and is supported for movement on the switchgear frame. A drive mechanism connects the truck and is configured to rack in the truck into an electrically connected position with the at least one electrical switchgear component, rack out the truck from the electrically connected position into an electrically disconnected position, and rotate the truck upward from its disconnected position into a rotated position to allow operator access through the front opening to the at least one electrical component.