An objective of the invention is to provide a bidirectional power valve for current occurring in a high voltage DC conductor, control method therefor, hybrid multi-terminal HVDC System using the same. The bidirectional power valve includes a first power diode arrangement of a first conducting direction, a second power diode arrangement of a second conducting direction; a mechanical disconnector, being connected with the second power diode arrangement in series; wherein: the first power diode arrangement and the series-connected second power diode arrangement and the mechanical disconnector are connected in parallel; and the first conducting direction of the first power diode arrangement and the second conducting direction of the second power diode arrangement are opposite to each other. The current commutation and re-commutation can be achieved with less requirement of the timing accuracy of switching event which makes the usage of a mechanical disconnector and power diode feasible. This will then result in a significant reduction of cost and power transfer losses.

A circuit-breaker device, comprising a main branch and an auxiliary branch electrically in parallel with the main branch, wherein the main branch comprises at least one mechanical switch-disconnector in series with a breaker cell constituted of at least one semiconductor switch, and a snubber circuit in parallel with the at least one breaker cell, the snubber circuit including an energy storage element, wherein the mechanical switch-disconnector is switchable to selectively allow current to flow in the main branch in a first mode of operation or commutate current from the main branch to the auxiliary branch in a second mode of operation, characterized in that the snubber circuit further comprises a bleeder resistor arranged to create a counter current in the main branch when current is commutated from the main branch to the auxiliary branch by discharging the energy storage element.

In order to provide a DC interrupting device that does not easily cause erroneous melting of current-limiting fuses at normal times with no fault current, and that can also deliver good current-limiting performance at the time of occurrence of fault current, the DC interrupting device includes: a (k1)th current path including a (k1)th current-limiting fuse, where k is an integer of not less than two and not more than N, and N is an integer of not less than two; and a kth current path connected in parallel to the (k1)th current path and including a kth current-limiting fuse. The inductance value of the inductance component of the kth current path is higher than the inductance value of the inductance component of the (k1)th current path.

A switching device includes a number of line sections corresponding to a number of phases, each including a first and a second connection part, for connection to a connection phase of an electrical consumer. At least one controllable semiconductor switching element is provided per phase, wired between the first and second connection part. A bypass unit includes one controllable electromechanical switching element with a low on-resistance per phase. The controllable electromechanical switching element is wired, in parallel with the controllable semiconductor switching element of this phase, between the first and second connection part. The first and second connection part of a respective phase are arranged adjacently on one side of the power module in spatial proximity in a direction of extent. A contact bridge, assigned to a respective phase, runs in the direction of extent in order to electrically connect the first and second connection part in the switched-on state.

A connecting device may electrically connect an electric motor to an electronic switchgear unit. The connecting device may include a bus bar that has a first interface, a second interface, and a linear section therebetween, where the first interface is bowed in a direction at least partially transverse to a longitudinal direction of the linear section of the bus bar. The first interface may be configured to electrically connect to at least one line that conducts a drive current of the electric motor through a crimp connection, and the second interface may be configured to electrically connect to the electronic switchgear unit.

In the field of power distribution networks, a digital output circuit, for controlling an item of equipment within a power distribution network, comprises a switch element openable and closeable to selectively permit the flow of current to an item of equipment being controlled in use by the digital output circuit. The digital output circuit also includes a current acquisition circuit to measure the current flowing through the switch element. In addition, the digital output circuit includes a condition monitoring circuit that is arranged in communication with the current acquisition circuit. The condition monitoring circuit is configured to record the measured current flowing through the switch element as the switch element closes and thereby establish a switch element closing signature.

[Problem] A new and improved arc suppression device is provided that allows for reduction in power consumption in a semiconductor at a time of power shutoff by reducing power consumption of a current-limiting circuit that is used for suppression of an arc occurring at the time of power shutoff. [Solving means] Provided is an arc suppression device including one or more current-limiting circuits provided in parallel with a circuit breaker that switches between feeding and shutoff of power from a power supply. The current-limiting circuit shuts off a current from the power supply when the power from the power supply is fed to a load through a circuit breaker. The current from the power supply is shut off when a voltage generated by a potential difference between contacts of the circuit breaker becomes a predetermined voltage or higher in a case where feeding of the power from the power supply to the load is shut off by the circuit breaker. The potential difference is generated upon shutoff.

Within a direct current hybrid circuit breaker (DC HCB), a commutation unit (CU) is provided in a semiconductor switch path in series with a semiconductor switch to facilitate opening the DC HCB. The semiconductor switch path is connected in parallel with a mechanical switch path that includes a mechanical switch. The CU is a controlled voltage source which applies a reverse biased voltage on the semiconductor switch path. The CU causes the current through the mechanical switch to ramp down while the current through the semiconductor switch ramps up to a supply current. The CU maintains the current through the mechanical switch to remain at a zero vale by compensating for the voltage drop across the semiconductor switch and the self-inductance of the semiconductor switch path. The mechanical switch can open without current and against no recovery voltage.

A DC high-voltage electrical installation comprises a switching device for switching an electric current in the main circuit, and a method for controlling the closure of a switching device in such an installation. The installation includes a controlled variable resistor system making it possible to modify the resistance value of the resistor system seen by the current flowing through the main electrical circuit. The resistance value takes at least three distinct values: high, a lower value, and at least one nonzero intermediate value comprised between the high value and the low value. The installation includes a coordination device making it possible to control switching times of the resistance values of the resistor system.

A load driving device is configured to reduce erroneous blocking operation in a switch. The load driving device includes: a control unit configured to output a driving signal and a non-driving signal; a first switch unit configured to switch power between a power supply unit and a load to a conductive state and a non-conductive state, and switch the power path to a conductive state when a difference between a potential of the first input line and a potential of a conducting path on the load side is greater than a predetermined value; and a second switch unit configured to connect a power supply to the first input line into a conductive state upon the control unit outputting the driving signal, and to block conduction between the power supply path and the first input line upon the control unit outputting the non-driving signal.