Abstract: There is provided a switching apparatus (30,130) comprising: first and second nodes (32,34) operably connectable to a line voltage (44); first and second switching branches (38,40) connected in parallel between the first and second nodes (32,34), the first switching branch (38) including at least one first switching element (46,60); and the second switching branch (40) including a pair of switching assemblies connected in series between the first and second nodes (32,34), the second switching branch (40) further including a junction (48) between the pair of switching assemblies, each switching assembly including at leastone second switching element (50), at least one of the switching assemblies further including at least one impedance element (52), wherein the switching apparatus (30,130) further includes a shunt impedance (42) and a third node (36), the shunt impedance (42) arranged to form a permanent electrical connection between the junction (48) and the third node (36), the third node (36) operably conne

Abstract: In the field of monitoring assemblies for gas tube switching devices which is operable in a plurality of different conducting modes, a monitoring assembly includes a monitoring module to distinguish in real time at least one conducting mode from the or each other conducting mode.

Abstract: A switching apparatus comprises: a plurality of parallel-connected current-conductive branches, each current-conductive branch including at least one respective gas tube switch; and a switching control unit configured to control the turn-on of the gas tube switches in a switching order so that the flow of current in the switching apparatus is controlled to switch between the current-conductive branches, wherein the switching order of the turn-on of the gas tube switches is arranged so that only one of the current-conductive branches is carrying the current during each turn-on cycle of the switching apparatus.

Abstract: In the field of high voltage direct current (HVDC) power transmission a line commutated converter (10) includes a plurality of converter limbs (12A, 12B, 12C) that extend between first and second DC terminals (16, 18). Each converter limb (12A, 12B, 2C) includes first and second limb portions (22, 24) that are separated by an AC terminal (26). The first limb portions (22) together define a first limb portion group (28) and the second limb portions (24) together define a second limb portion group (30). Each limb portion (22, 24) includes at least one switching element (32) in the form of a latching device (34). Each latching device (34) is configured to turn on and conduct current when it is forward biased and it receives a turn on signal, to naturally turn off and no longer conduct current when it is reverse biased and the current flowing through it falls to zero, and to actively turn off and prevent current from flowing therethrough when it receives a turn off signal.

Abstract: A switching apparatus comprises a plurality of current-conductive branches connected in parallel between first and second terminals, each current-conductive branch including at least one respective electrical connection member in series connection with at least one respective gas tube switch between the first and second terminals, wherein the inductance value of each electrical connection member is configured to balance the inductance values of the current-conductive branches.

Abstract: A switching apparatus comprises a plurality of parallel-connected current-conductive branches, each current-conductive branch including at least one respective gas tube switch, wherein the switching apparatus further includes an electrical circuit, the electrical circuit including at least one switching element configured to be operable to selectively synthesise a or a respective voltage difference in series with one or more of the gas tube switches so as to control the distribution of current between the current-conductive branches.

Abstract: In the field of gate drivers there is provided a regulated voltage source (10; 10A, 10B), for a gate driver (200; 300) of a switching device (18) having a gate terminal (26) via which the switching device (18) can at least be turned on. The regulated voltage source (10; 10A, 10B) comprises an input terminal (12) via which the regulated voltage source (10; 10A, 10B) in use receives current. The regulated voltage source (10; 10A, 10B) also includes first and second connection terminals (22, 24) via at least one of which the regulated voltage source (10; 10A, 10B) in use applies a voltage (V) to a gate terminal (26) of a switching device (18).

Abstract: A semiconductor switching circuit, for use in a HVDC power converter, comprising: a main semiconductor switching element, including first and second connection terminals between which current flows from the first connection terminal to the second connection terminal and an auxiliary semiconductor switching element electrically connected between the first and second connection terminals thereof, and a control unit, operatively connected to auxiliary semiconductor switching element and programmed to control the switching element to create an alternative current path between the first and second connection terminals by at least two of: a fully-on mode in which the switching element is operated at its maximum rated base current or gate voltage; a pulsed switched mode in which the switching element is turned on and off; and an active mode in which the switching element is operated with a continuously variable base current or gate voltage.

Abstract: There is provided a power supply apparatus for supplying power to an external electrical load , including a power transmission line or cable through which an alternating or direct current may flow, a power supply module, a control unit, an output terminal for connection to the external electrical load, and a converter. The power supply module includes an input terminal connected to the power transmission line or cable, and includes switching elements and energy storage device(s). The control unit controls the switching elements to selectively switch each energy storage device into circuit to direct a current flowing in the power transmission line or cable to flow through each energy storage device so as to store energy to form a power source. The converter draws power from the power source and supplies the drawn power to the output terminal.

Abstract: An electrical assembly including a primary electrical component having a semiconductor device, a primary heat sink having the primary electrical component mounted thereon to provide a heat sink for said primary electrical component, a secondary electrical component electrically connected or coupled with the primary electrical component, a secondary heat sink having the secondary electrical component mounted thereon to provide a heat sink for said secondary electrical component, wherein the primary heat sink and the secondary heat sink are physically releasably couplable to one another and, when coupled, the primary and secondary heat sinks are thermally coupled by abutment of heat transfer surfaces of the primary and secondary heat sinks.

Abstract: A switching device (28) comprising a primary switching block (30) including at least one semiconductor switch (34); and a switching control unit (32) to control the switching of the or each semiconductor switch (34). The switching device further includes a crowbar circuit (46) comprising a crowbar switch (56) switchable to selectively allow current to flow through the crowbar switch (56) in order to bypass the or each switching module; and a secondary switching block including a switching element (58) connected across a control electrode and a cathode of the crowbar switch (56). The switching element (58) is in communication with the switching control unit (32) to receive, in use, a control signal (66) generated by the switching control unit (32) when the primary switching block (30) is operating within predefined operating parameters.

Abstract: The control circuit includes first and second primary terminals for connection to a DC network, a secondary terminal connected in series between the first and second primary terminals and at least one auxiliary energy conversion element and an auxiliary terminal. The first and second primary terminals have a plurality of modules and a plurality of primary energy conversion elements connected in series therebetween to define a current transmission path, each module including at least one energy storage device, each energy storage device being selectively removable from the current transmission path.

Abstract: A semiconductor switching string including a series-connected switching assemblies. Each assembly has a main switching element including first and second connection terminals which current flows between when the main switching element is on. The main element has an auxiliary element between the connection terminals. The string includes a local control unit connected with each auxiliary element which are programmed to switch an auxiliary element to create an alternative current path between the connection terminals that diverts current through to reduce the voltage across the corresponding main switching element. The local unit is programmed to control switching an auxiliary element to a fully-on mode in which the auxiliary element is at maximum rated base current, a pulsed mode which turns the auxiliary element on and off and/or an active mode operating the auxiliary element with a continuously variable base current. The string includes a higher level control unit programmed to implement the modes.

Abstract: A DC breakers and in particular to DC breaker modules suitable for use in a high voltage DC circuit. The breaker module comprises at least a first breaker circuit (enclosed within a conductive enclosure. The enclosure is configured such that the first breaker circuit can be connected (in an electrical path with a circuit external to the conductive enclosure. The conductive enclosure is further configured to be connected to a node of the electrical path such that, in use, the conductive enclosure is at the same voltage potential as the node of the circuit path. The conductive enclosure may be a standardised size and may, for example, be a standard shipping container. The methods and apparatus of the present application allow a DC breaker to be formed from modules that can be built, tested, transported and installed in a standardised enclosure.

Abstract: A semiconductor switching circuit, for use in a HVDC power converter, comprising: a main semiconductor switching element, including first and second connection terminals between which current flows from the first connection terminal to the second connection terminal and an auxiliary semiconductor switching element electrically connected between the first and second connection terminals thereof, and a control unit, operatively connected to auxiliary semiconductor switching element and programmed to control the switching element to create an alternative current path between the first and second connection terminals by at least two of: a fully-on mode in which the switching element is operated at its maximum rated base current or gate voltage; a pulsed switched mode in which the switching element is turned on and off; and an active mode in which the switching element is operated with a continuously variable base current or gate voltage.

Abstract: A semiconductor switching circuit includes a main current branch which includes at least one main semiconductor switching element and through which current flows in a first direction when the or each main semiconductor switching element is switched on. The semiconductor switching circuit also includes an auxiliary current branch that is connected in parallel with the main current branch. The auxiliary current branch includes at least one auxiliary semiconductor switching element. One or more control units are configured to switch on the or each auxiliary semiconductor switching element as the or each main semiconductor switching element is switched on to selectively create an alternative current path via the auxiliary current branch whereby current flowing in the first direction through the main current branch is diverted instead to flow through the alternative current path to reduce the rate of change of current flowing through the or each main semiconductor switching element.

Abstract: A semiconductor switching string includes a plurality of series-connected semiconductor switching assemblies, each having a main semiconductor switching element that includes first and second connection terminals. The main semiconductor switching element also has an auxiliary semiconductor switching element electrically connected between the first and second connection terminals. Each semiconductor switching assembly also includes a control unit configured to switch on a respective auxiliary semiconductor switching element to selectively create an alternative current path between the first and second connection terminals whereby current is diverted to flow through the alternative current path to reduce the voltage across the corresponding main semiconductor switching element.

Abstract: A current limiter for selectively limiting a rate of change of current in a DC electrical network may include a first electrical block including an inductive element and a second electrical block including a bidirectional switch. The first electrical block is connected in parallel with the second electrical block between first and second terminals, and the first and second terminals are connectable to the DC electrical network. The bidirectional switch is switchable to: (1) a first mode to permit current flow through the second electrical block in a first current direction and at the same time inhibit current flow through the second electrical block in a second, opposite current direction; and (2) a second mode to permit current flow through the second electrical block in the second current direction and at the same time inhibit current flow through the second electrical block in the first current direction.

Abstract: An electrical apparatus (10) comprises: first and second terminals (18,20) for connection to an electrical circuit; a chain-link converter (22) connected between the first and second terminals (18,20), the chain-link converter (22) including a plurality of chain-link modules (24), each chain-link module (24) including at least one switching element (26) and at least one energy storage device (28), the or each switching element (26) and the or each energy storage device (28) of each chain-link module (24) combining to selectively provide a voltage source; and a protection device (32) connected across an electrical block (34) that includes at least two of the plurality of chain-link modules (24), the protection device (32) including a plurality of series-connected semiconductor devices (36), wherein the protection device (32) selectively provides a current-conductive path to allow at least part of a current flowing in the electrical apparatus (10) to bypass the electrical block (34).

Abstract: An extinguishing branch (28) for an electrical circuit (32) includes: a snubber circuit (36) including an energy storage limb (40), wherein the energy storage limb (40) includes first and second energy storage limb portions separated by a first junction (46) to define a first voltage divider, and each energy storage limb portion includes at least one energy storage device (48,50); and an arrester limb (38) connected across the energy storage limb (40), wherein the arrester limb (38) includes first and second arrester limb portions separated by a second junction (52) to define a second voltage divider, and each arrester limb portion includes at least one arrester element (54,56), wherein the first and second junctions (46,52) are connected to define a voltage divider bridge, and the voltage divider bridge is electrically coupleable to the electrical circuit (32) so as to provide, in use, a driving voltage to drive the electrical circuit (32).