Systems and methods for power distribution may include a plurality of generation, distribution, and load nodes. A first generation node generates and transmits power to a first distribution node via a first transmission type, the first transmission type including MVDC or HVDC or LFAC. A second generation node generates and transmits power to a second distribution node via a second transmission type including HVAC. The first distribution node distributes the power to a first load node via the second transmission type, and distributes the power to a second load node via a third transmission type, the third transmission type including MVAC. The first load node transmits the power to a first subsea facility via one or more flow lines and the third transmission type. The second load node transmits the power to a second subsea facility via the one or more flow lines and the third transmission type.

The present disclosure relates to a submodule topology circuit for a modular multilevel converter and a method for controlling same. The submodule topology comprises an inlet port and an outlet port, at least two half-bridge submodules, a plurality of first switching devices, a plurality of thyristors and a plurality of diodes, wherein the at least two half-bridges are connected in series and are provided between the inlet port and the outlet port, and each of the half-bridge submodules is provided with an input port, a first output port and a second output port.

A supply device for a high-power load includes a DC/DC voltage converter disposed between a high-voltage side and a low-voltage side. The DC/DC voltage converter includes a first sub-converter and a second sub-converter. The sub-converters are connected to one another in a converter series circuit between first and second primary-side DC voltage poles. The second sub-converter is connected between first and second secondary-side DC voltage poles. The sub-converters each have at least one AC voltage terminal connected to one another by a coupling device to permit an exchange of electrical power between the first and second sub-converters. The secondary-side DC voltage poles are configured for connection to the high-power load. An arrangement for converting electrical energy into chemical energy with gas generation includes the supply device.

A modular multilevel converter includes a plurality of submodules, each having at least two electronic switching elements, an electric energy store, two submodule connections, a bypass switch bridging the submodule, and a communication element communicating with a communication apparatus. A method for operating the modular multilevel converter includes ascertaining that the submodules have a defective submodule so that the communication element in the defective submodule does not communicate with the communication apparatus, determining whether a present arm current resulting from an operating point of the modular multilevel converter is below a predetermined threshold value, and generating or amplifying a converter-internal circular current with the defective submodule if the arm current resulting from the operating point is below the predetermined threshold value. A modular multilevel converter is also provided.

A method for operating a converter-based grid unit disposed electrically within an AC voltage section or adjacently to an AC voltage section of an electrical grid and electrically connected to the AC voltage section, includes using a control device to adjust infeed and drawing of active power and/or reactive power into and from the AC voltage section by actuating at least one converter of the converter-based grid unit. A multiplicity of measurement values is transmitted to the control device. The measurement values at least relate to different measurement variables and/or measurement locations within the AC voltage section or the converter-based grid unit. The control device selects a measurement value group from the multiplicity of available measurement values by selecting in accordance with a predefined selection guideline, and the at least one converter is actuated based on measurement values of the selected measurement value group.

A power conversion device that performs power conversion between a DC circuit and an AC circuit includes a power conversion circuit including a plurality of sub-modules, a failure detection device that detects an internal failure of the power conversion circuit, and a control device that generates an operation command controlling operation of each of the plurality of sub-modules. The control device acquires a voltage value of a capacitor included in each sub-module, calculates a deviation between a variance value indicating a variation in the voltage value of the capacitor included in the sub-module in a reference period and a reference variance value in the sub-module for each of a plurality of sub-modules, determines a failure section of an internal failure based on the deviation in each sub-module when the internal failure is detected, and outputs an operation command based on a determination result to each sub-module.

In the field of high voltage direct current (HVDC) power transmission networks there is a need for an improved power converter. A power converter, for use in a HVDC power transmission network, comprises first and second DC terminals, for connection in use to a DC network and between which extends at least one converter limb. The or each converter limb includes first and second limb portions which are separated by an AC terminal, for connection in use to an AC network. Each limb portion includes a switching valve, and the power converter including a controller programmed to control switching of the switching valves to control the flow of a converter current (I.sub.max) through the power converter and thereby in-use transfer power between the power converter and the AC network. The power transferred between the power converter and the AC network has an active component and a reactive component. The controller is further programmed in use to: (i) prioritize to a first extent the transfer of reactive power between the power converter and the AC network during a first operating condition, when the AC voltage (V) of the AC network lies outside a desired operating range, by allowing up to a first amount of the converter current (I.sub.max) to be a reactive current; and (ii) prioritize to a second extent, less than the first extent, the transfer of reactive power between the power converter and the AC network during a second operating condition, when the AC voltage (V) of the AC network lies within the desired operating range, by limiting the amount of converter current (I.sub.max) that can be a reactive current to a second amount, less than the first amount, the second amount being determined according to a measured operating frequency of the AC network.

A converter has an AC side to connect to an AC network. A converter control is configured to set a current reference limit to limit a converter current. The converter control is configured to reduce the limit in case a fault is detected in the AC network. There is also described a combination of the converter in a power system with a renewable power source and a corresponding method of operating a converter in a power system with a renewable power source.

The present disclosure relates to a voltage source converter (VSC) (300) comprising: a first MOSFET switching element (302) including a first body diode (306); a second MOSFET switching element (304) including a second body diode (308), the second MOSFET switching element (304) being connected in series with the first MOSFET switching element (302); a protection device (318) connected in parallel with the second MOSFET switching element (304); and a controller (312), wherein the controller (312) is configured, on detection of an overcurrent event, to: switch off the first MOSFET switching element (302); and switch off the second MOSFET switching element (304), thereby forcing current flowing in the VSC (300) following the overcurrent event to flow through the second body diode (308) rather than through conducting channels of the first and second MOSFET switching elements (302, 304).

In the field of chain-link converters operable to provide a stepped variable voltage source, there is a need for an improved method of operating such a chain-link converter. A method of operating a chain-link converter, the chain-link converter including a number of series connected chain-link modules, each chain-link module including at least one switching element and an energy storage device which together are selectively operable to provide a voltage source whereby the chain-link converter is able to provide a stepped variable voltage source, including the steps of: (i) identifying one or more unhealthy chain-link modules having a reduced performance characteristic compared to one or more healthy chain-link modules having a normal performance characteristic, (ii) utilizing the healthy chain-link modules normally in the operation of the chain-link converter, and (iii) reducing the utilization of the or each unhealthy chain-link module.