Abstract: There is provided a switching valve for a voltage source converter, the switching valve including a number of modules, each module including at least one switching element and at least one energy storage device, each switching element and each energy storage device arranged to be combinable to selectively provide a voltage source, the switching valve including a controller programmed to selectively control the switching of the switching elements to select zero, one or more of the modules to contribute a or a respective voltage to a switching valve voltage. The controller is programmed to selectively control the switching of the switching elements to carry out a switching operation and to apply a time delay if a charging current is flowing through the modules and/or apply a time delay to a start time of the switching operation if a discharging current is flowing through the modules.

Abstract: The present disclosure relates to a phase shifting transformer. The phase shifting transformer includes two exciting windings sharing the same three double taped coils, a first excited winding having three connected coils, for a phase shift regulation, a second excited winding comprising three connected coils, for a voltage regulation, each of the two exciting windings regulating the voltage of one coil of the second excited winding, and regulating the voltage level of one coil of the first excited winding.

Abstract: A DC energy storage system may include first and second DC terminals for connection to a DC link, a DC energy storage converter including a number of modules connected in series between the first and second DC terminals, each module including at least one switching element and at least one energy storage device, the or each switching element and the or each energy storage device in each module being combinable to selectively provide a voltage source, and at least one circuit interruption device connected in series with the DC energy storage converter between the first and second DC terminals, the or each circuit interruption device operable to electrically separate the DC energy storage converter from the DC link.

Abstract: A DC energy storage system may include first and second DC terminals for connection to a DC link, a DC energy storage converter including a number of modules connected in series between the first and second DC terminals, each module including at least one switching element and at least one battery, the or each switching element and the or each battery in each module being combinable to selectively provide a voltage source, and at least one fire-resistant protective barrier arranged to separate the modules into converter sections, each converter section including at least one module of the number of modules.

Abstract: A voltage source converter includes first and second DC terminals which have at least one converter limb extending therebetween. Each limb portion includes a chain-link converter that extends between an associated AC terminal and a corresponding one of the first or the second DC terminal. Each chain-link converter also includes a chain-link converter controller which is programmed to control a series of connected chain-link modules. The voltage source converter additionally includes a voltage source converter controller which is arranged in operative communication with each chain-link converter controller to coordinate operation of the chain-link converters. Each chain-link converter controller is further programmed to reconstruct from a received modulation index demand the chain-link converter voltage reference, which the chain-link converter it is controlling is required to produce, by multiplying the received modulation index demand by a total voltage sum established at a first time instant.

Abstract: A chain-link converter includes a number of series-connected chain-link modules. Each chain-link module has a module controller that is programmed to control operation of the corresponding chain-link module to selectively provide a voltage source, whereby the chain-link converter is able to provide a stepped variable voltage source. The chain-link converter also includes a chain-link converter controller that is arranged in communication with each module controller, and which is programmed to, in-use, communicate to a nmber of the module controllers a measured converter current (IDC) that is flowing through the chain-link converter. The module controllers that receive the measured converter current (IDC) is each further programmed, in-use, to combine the measured converter current (IDC) with a measured rate of change of current (IAC) flowing through the corresponding chain-link module, to establish an instantaneous module current (Ii) that is flowing through the corresponding chain-link module.

Abstract: Air-core reactors for use with power transmission systems are disclosed. An example air-core reactor may include a main coil and an auxiliary coil. The main coil may include a first solenoid having a first diameter and a second solenoid having a second diameter, wherein the first diameter and the second diameter are different. The auxiliary coil may include a third solenoid. The first solenoid and the second solenoid may be arranged concentrically. The auxiliary coil may also be magnetically coupled to the main coil, and the auxiliary coil may be arranged concentric to the main coil.

Abstract: There is provided an electrical assembly including at least one power converter and at least one dynamic reactive power source, the or each power converter and the or each dynamic reactive power source connectable to an AC network, the or each power converter and the or each dynamic reactive power source operable to exchange reactive power with the AC network, wherein the or each dynamic reactive power source is configured to selectively adjust its exchange of reactive power with the AC network in response to a characteristic of a reactive current demand of the or each power converter crossing a or a respective reactive current characteristic threshold.

Abstract: A controller, for a chain-link converter having a number of series-connected chain-link modules that are operable in combination to provide a stepped variable voltage source, is programmed to obtain for each chain-link module an indication of whether the current flow through the corresponding chain-link module is in a first flow direction or a second flow direction. The controller is additionally programmed to evaluate the number of indications in the first flow direction and the number of indications in the second flow direction, and thereafter to establish an overall current flow direction through the chain-link converter equal to the flow direction having the largest number of indications.

Abstract: A bipole power transmission scheme typically includes a first converter station that is positioned remote from a second converter station, along with first and second transmission conduits which interconnect the first and second converter stations to permit the transmission of power between the first and second converter stations. The first converter station has first and second power converters, with the first power converter including a first DC terminal that is connected with the first transmission conduit, at least one AC terminal which is connected with a first AC network, and a second DC terminal that is interconnected with a third DC terminal of the second power converter by a first interconnection which defines a first neutral area. The second power converter additionally includes a fourth DC terminal that is connected with the second transmission conduit and at least one AC terminal which is connected with a second AC network.

Abstract: A bipole power transmission network includes a first upstream power converter which has a first DC terminal that is connected with a first transmission conduit which extends, in-use, to a first downstream power converter. The first upstream power converter has a second DC terminal that is connected with a return conduit which extends, in-use, to the first downstream power converter and a second downstream power converter. The first upstream power converter has at least one first AC terminal electrically connected with a first AC power source. The bipole power transmission network includes a second upstream power converter which has a third DC terminal that is connected with the return conduit, and a fourth DC terminal which is connected with a second transmission conduit that extends, in-use, to the second downstream power converter, and at least one second AC terminal electrically connected with a second AC power source.

Abstract: An electronic valve apparatus for a high voltage direct current, HVDC, power transmission system. The electronic valve apparatus includes a first device chain including a number of first devices connected in series between an input node and an output node. Each of the first devices has an asymmetric transfer function configured substantially to block current flow through the device in a first direction, and the first devices are connected such that they all block current flow in the same direction. The electronic valve apparatus also includes a second device chain including a number of second devices connected in series between the input node and the output node. Each of the second devices has an asymmetric transfer function configured substantially to block current flow through the device in a first direction, and the second devices are connected such that they all block current flow in the same direction.

Abstract: A converter including a first terminal and a second terminal, the first terminal configured for connection to a first network, the second terminal configured for connection to a second network; at least one switching module arranged to interconnect the first terminal and the second terminal, the switching module including at least one module switching element and at least one energy storage device, the module switching element and the energy storage device arranged to be combinable to selectively provide a voltage source, the switching module switchable to control a transfer of power between the first and second networks; the switching module including a discharge circuit, the discharge circuit including a discharge switching element and a discharge resistor, the discharge switching element switchable to switch the corresponding discharge resistor into and out of the corresponding switching module; and a controller configured to selectively control the switching of the discharge switching element.

Abstract: This application relates to methods and apparatus for handling a fault associated with a voltage source converter (VSC) for exchanging electrical power between an AC system (101, 102) and a DC system (106-1, 106-2). The VSC (104) is connected to the AC system via an interface apparatus, comprising a transformer (107) with a set of primary windings (202) for coupling to a plurality of AC phases (A, B, C) of the AC system. In embodiments of the disclosure the set of primary windings having a neutral point (N) and the interface apparatus includes a fault module (301) having an energy storage element (302) connected in parallel with a resistive element (303) between the neutral point of the set of primary windings and a reference voltage, such as ground.

Abstract: Systems and methods for power system switching element (PSSE) anomaly detection are disclosed. An example PSSE anomaly detection unit may include a power system switching element position estimator (PSSEPE) and a comparison unit. The PSSEPE may be configured to receive a set of measurements and a set of control commands associated with a PSSE, calculate an anomaly confidence score based on the set of measurements and the set of control commands, and estimate a calculated PSSE position based on the set of measurements and the set of control commands. The comparison unit may be configured to receive the calculated PSSE position from the PSSEPE, receive the set of measurements and the set of control commands from the PSSEPE, receive a reported PSSE position associated with the PSSE, and determine a PSSE anomaly decision based on a difference between the reported PSSE position and the calculated PSSE position.

Abstract: A Ni-based superalloy composition to be used for powder-based additive manufacturing (AM) technology, such as selective laser melting (SLM) or electron beam melting (EBM). The cracking susceptibility during an AM process is considerably reduced by controlling the amount of elements, especially Hf, that form low-melting eutectics.

Abstract: The present application concerns a transformer assembly. The transformer assembly includes a step-up transformer, a step-down transformer, and a phase shifting transformer having a source side and a load side connected, respectively, to the step-down transformer and the step-up transformer.

Abstract: Soluble water scavenger molecules for use with dielectric fluids are disclosed. An example dielectric fluid-based composition for reducing water content in a dielectric fluid may include a water-scavenging agent disposed within a dielectric fluid. The example dielectric fluid-based composition may further include the water-scavenging agent being soluble in the dielectric fluid. The example dielectric fluid-based composition may further include the water-scavenging agent being configured to react with water molecules in the dielectric fluid. The example dielectric fluid-based composition may be disposed in an electrical equipment immersed in oil. The electrical equipment may further include at least one solid insulation in operational contact with the dielectric fluid.

Abstract: Systems and methods are disclosed for voltage-less electrical signature analysis for fault protection. The systems and methods described herein may involve determining voltage values for a motor (which may then be used to estimate a speed of the motor) when complete voltage measurements may not be available, or may only be temporarily available. More specifically, the systems and methods described herein may address three scenarios, which may include at least: (1) when only a single phase voltage input is available for a three-phase motor, (2) when no voltage input is available, or (3) when a voltage input is only available for a limited period of time (for example, during a learning phase of the motor).

Abstract: A voltage source converter having first and second DC terminals for connection to a DC network is provided. The voltage source converter includes at least one converter limb that extends between the first and second DC terminals and first and second limb portions that are separated by a respective AC terminal for connection to a corresponding phase of an AC network. Each limb portion includes a chain-link converter which is defined by a plurality of series-connected switching modules which operate in combination to provide a stepped variable voltage source. The voltage source converter includes a control apparatus configured to coordinate operation of the chain-link converters to cause an exchange of power between the DC and AC networks, evaluate the performance of one of the pluralities of series-connected switching modules, and modify the operation of the respective chain-link converter when the performance becomes degraded to a predetermined amount.