Abstract: There is provided methods and apparatus configured to provide electrical converter control parameters, the apparatus comprising: a Structured H-infinity tuning module configured to determine one or more control parameters, for a model of an electrical converter control system and grid, based on variation of one or more grid parameters; and an output module configured to provide the one or more control parameters for implementation in the electrical converter control system.

Abstract: An electrical assembly comprises a power converter including first and second DC terminals and an AC terminal. The electrical assembly also includes a grounding circuit to connect the AC terminal to ground. The grounding circuit defines first and second current flow paths between the AC terminal and ground. The first current flow path includes a switching element. The second current flow path includes a first current flow control element that is configured to operate in a first mode in which it reduce the flow of current between the AC terminal and ground when the first current flow path is open. The electrical assembly additionally includes a control unit configured to operate the switching element to maintain open the first current flow path following an occurrence of a DC network fault. The power converter is configured to continue transferring power between the DC and AC networks throughout the DC network fault.

Abstract: A voltage limiter includes first and second DC terminals connectable to a DC power transmission medium and ground, respectively. The voltage limiter further includes: (1) a current transmission path including two portions connected in series between the terminals and each including a non-linear resistive element; (2) a current bypass limb connected in parallel with the second portion and including at least one switching element; and (3) a control unit configured to control switching of the or each switching element to selectively switch the current bypass limb, during a fault condition, from a first mode to a second mode. In the first mode, current flows through the current bypass limb and bypasses the second current transmission path portion. In the second mode, current between the DC terminals is inhibited from flowing through the current bypass limb and thereby permits the current to flow through the second portion.

Abstract: A power transmission network includes a first power transmission medium. The power transmission network further includes a first insulator or a plurality of first insulators arranged to provide insulation of the first power transmission medium with respect to ground potential. The power transmission network further includes a converter operably connected to the first power transmission medium, the converter including a first ground connection to operably connect the converter to ground. Additionally, an impedance of the first ground connection is configured to control a current flowing between the converter and ground via the first ground connection when the or each first insulator experiences an insulation failure and thereby limit a converter current flowing into a resultant electrical arc to be at or below a current threshold that prevents maintenance of the flashover arc.

Abstract: An electrical assembly comprises a power converter including first and second DC terminals and an AC terminal. The electrical assembly also includes a grounding circuit to connect the AC terminal to ground. The grounding circuit defines first and second current flow paths between the AC terminal and ground. The first current flow path includes a switching element. The second current flow path includes a first current flow control element that is configured to operate in a first mode in which it reduce the flow of current between the AC terminal and ground when the first current flow path is open. The electrical assembly additionally includes a control unit configured to operate the switching element to maintain open the first current flow path following an occurrence of a DC network fault. The power converter is configured to continue transferring power between the DC and AC networks throughout the DC network fault.

Abstract: A power electronic converter for use in high voltage direct current power transmission and reactive power compensation which includes at least one converter limb including first and second DC terminals for connection in use to a DC network. The or each converter limb includes at least one first converter block and at least one second converter block connected between the first and second DC terminals. The or each first converter block includes a plurality of line-commutated thyristors and at least one first AC terminal for connection in use to an AC network. The or each second converter block includes at least one auxiliary converter including a plurality of self-commutated switching elements. The self-commutated switching elements are controllable in use to inject a voltage to modify a DC voltage presented to the DC side of the converter limb and/or modify an AC voltage and an AC current on the AC side of the power electronic converter.

Abstract: A power electronic converter for use in high voltage direct current power transmission and reactive power compensation which comprises at least one converter limb including first and second DC terminals for connection in use to a DC network, the or each converter limb including at least one first converter block, and at least one second converter block connected between the first and second DC terminals; the or each first converter block including a plurality of line-commutated thyristors and at least one first AC terminal for connection in use to an AC network, the or each second converter block including, at least one auxiliary converter including a plurality of self-commutated switching elements; wherein the self-commutated switching elements are controllable in use to inject a voltage to modify a DC voltage presented to the DC side of the converter limb and/or modify an AC voltage and an AC current on the AC side of the power electronic converter.