Abstract: 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 (Imax) 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.

Abstract: A grounding arrangement for a Voltage Source Converter (VSC) in a power transmission system is provided. The VSC comprises at least one converter branch (20) comprising at least one module (221-22N), each module comprising a plurality of serially connected sub-modules (241-248) that can be controllably switched to generate a controlled voltage across the module (221-22N) and each module including a first sub-module (241) at one end thereof and a last sub-module (248) at an opposite end thereof. Each sub-module (241-248) includes a first terminal (381), a second terminal (382), an energy storage element (30) and a switching arrangement (32, 34), wherein at least one of the first (381) or second terminals (382) is coupled to a terminal of the energy storage unit (30).

Abstract: A steam generating system includes a furnace, a nozzle tip assembly for pulverized coal and primary air as well as means for conveying secondary air in the furnace. The nozzle according to the invention comprises a nozzle body (3) and several channels (5) being connected with the nozzle body, the channels are diverging from each other. At the exit faces (17) of the channels obstructions (13) are disposed to induce huge turbulences of the primary air when entering the furnace. Due to these turbulences the primary air and the entrained coal are mixed very well before being combusted in the furnace. This results in a better more effective combustion with reduced NOx-emissions.

Abstract: The application relates to certain embodiments of an improved insulating support assembly for a circuit breaker. One embodiment comprises a strut and two metallic shields. The strut comprises an elongated main body and two metallic inserts. The main body is continuously curved from one end to the other end of the main body, each end of the main body being configured to face a radial direction of its component, the main body being configured to be in a same plane as a plane containing both radial directions of the components; each metallic shield is configured to be assembled to its respective end of the main body through its respective metallic insert and affixed to an outer surface of its respective component with fixing elements, each metallic shield having a C-shaped profile shaped to accommodate the outer surface of its respective component.

Abstract: A DC circuit breaker includes a gas discharge tube (GDT) coupled in parallel with an extinguishing path. The GDT conducts and interrupts a load current through a normal current path. The GDT includes a thermionic cathode, an anode, and a control grid. The control grid is configured to regulate opening and closing of the normal current path. The extinguishing path is configured to lengthen a break time for the DC circuit breaker.

Abstract: A converter scheme (30) comprises a plurality of poles and a plurality of converters (32), the plurality of poles (60,62,64) including at least one positive pole (60), at least one negative pole (62) and a neutral pole (64), the plurality of converters (32) including at least one first converter (32a) and at least one second converter (32b), the or each first converter (32a) connected to the neutral pole (64) and the or the respective positive pole (60), the or each first converter (32a) operable to control a converter voltage across the neutral pole (64) and the corresponding positive pole (60), the or each second converter (32b) connected to the neutral pole (64) and the or the respective negative pole (62), the or each second converter (32b) operable to control a converter voltage across the neutral pole (64) and the corresponding negative pole (62), wherein the converter scheme (30) includes a controller (36) programmed to perform a voltage control mode when there is an imbalance between power or current

Abstract: The invention lies in the field of current stabilisation in a power generation system comprising a plurality of elementary power groups connected in parallel. It relates to a control system for regulating the elementary power groups. According to the invention, the control system comprises a global current control system (510) and a plurality of local current control systems each associated with an elementary power source of the power generation system.

Abstract: An apparatus for breaking apart a substance is provided. The apparatus includes a body configured to be selectively secured via a fastener between two surfaces of a container and to break apart the substance upon impact. At least a portion of the body is operative to drop towards a bottom surface of the container upon removal of the fastener so as to facilitate removal of the substance from the container.

Abstract: The present application provides a method of adjusting a feedwater mass flow rate to maintain a constant steam temperature in an evaporator section. The method may include the steps of determining a change in a number of operational parameters, predicting a change in steam temperature based on the number of operational parameters, combining the predicted changes in steam temperature, determining a feedforward signal based on dynamically offsetting the combined predicted changes in steam temperature, and changing the mass flow rate of feedwater based on the feedforward signal.

Abstract: In the field of power transmission networks, particularly high voltage direct current (HVDC) power transmission networks, there is provided an electrical assembly (10). The electrical assembly (10) comprises a converter (12) that includes at least one AC terminal (14A, 14B, 14C) for connection to an AC network (16) and at least one DC terminal (18, 22) which is operatively connected to a DC power transmission medium (20, 24). The electrical assembly (10) also includes a signal injection circuit (32) which is operatively coupled with at least one DC power transmission medium (20, 24). The signal injection circuit (32) includes a signal generator (38) to selectively inject a plurality of different frequency signals into the said at least one transmission medium (20, 24). In addition the signal injection circuit (32) includes a signal analyser (42) to establish a response signature of the said at least one transmission medium (20, 24) to the plurality of different frequency injected signals.

Abstract: A system for controlling an electrostatic precipitator includes a computer control system with a computer and a controller in operative communication with an electrostatic precipitator. The computer control system is operative to control performance of the electrostatic precipitator by controlling one or more of: a) a power supply that controls voltage between an electrically grounded vertical plate and a metallic wire electrode in the electrostatic precipitator; b) a first feeder valve and a second feeder valve in a hopper; and c) a power supply to an electrical coil in operative communication with a rapper.

Abstract: This application relates to a cell (1200) or sub-module for a voltage source converter (1201). The cell includes an energy storage apparatus (101; 101a, 101b) and a plurality of dual-switch semiconductor packages (201), each having first and second semiconductor switches (202, 203) connected in series. The cell is operable in an active state in which an energy storage apparatus (101; 101a, 101b) is electrically connected in series between cell terminals (102a, 102b) and a bypass state in the cell terminals (102a, 102b) are electrically connected via a path that bypasses the first energy storage apparatus.

Abstract: A communication system is provided that include one or more processors that are configured to instruct computing devices that communicate messages with each other via a time-sensitive network to securely exchange the messages using secret information, ad direct the computing devices to exchange the secret information via a dedicated quantum channel in the time-sensitive network. The one or more processors are also configured to determine a quantum channel synchronization time associated with the secret information exchanged via the dedicated quantum channel, and modify a local classical oscillator based on the quantum channel synchronization time, the local classical oscillator configured to provide a current time.

Abstract: In the field of power system stability there is provided a method of predicting the presence of an out-of-step condition in a power system that includes a plurality of generators, the method including the steps of: (a) obtaining a differential value ({tilde over (?)}COIk) between a rotor angle (?k) of an individual one of the plurality of generators and an equivalent rotor angle (?COIk) of the centre of inertia of the remainder of the plurality of generators; (b) processing the differential value ({tilde over (?)}COIk) to determine whether the differential value ({tilde over (?)}COIk) is predicted to reach a predefined reference threshold (?threshold); and (c) predicting the presence of the out-of-step condition in the power system if the differential value ({tilde over (?)}COIk) is predicted to reach the predefined reference threshold (?threshold).

Abstract: A protection relay connection assembly (10) for connecting a current transformer (14) and/or a voltage transformer (16) of an electrical network (12) to a protection relay (18) is provided. The protection relay connection assembly (10) includes a protection relay data acquisition board (20) and a protection relay connector (22). The protection relay data acquisition board (20) includes a first current mating member (24) connectable to a current measurement sensor (28), the current measurement sensor (28) being connectable in use to the protection relay (18) and/or a first voltage mating member (26) connectable to a voltage measurement sensor (30), the voltage measurement sensor (30) being connectable in use to the protection relay (18). The protection relay connector (22) includes a second current mating member (36) connectable to the current transformer (14) and/or a second voltage mating member (38) connectable to the voltage transformer (16).

Abstract: A disconnector to reduce considerably high voltage and high frequency current generated during the service no-load opening and closing, the disconnector comprising a first main contact a second main contact, a sliding contact and an arcing horn having a length, the disconnector having a connected state, an intermediate state and a disconnected state, wherein in the connected state a first electrical contact is established between the first main contact and the second main contact, in the intermediate state the first electrical contact is interrupted while a second electrical contact exists between the sliding contact and a contact position on the length of the arcing horn, and in the disconnected state the first electrical contact and the second electrical contact are interrupted, wherein at least a part of the length of the arcing horn comprises an electrical filter configured to provide a resistance and an inductance to an electrical current.

Abstract: The invention relates to a universal vacuum interrupter (UVI) (30) for an air disconnect switch (100) comprising a rotatable actuating arm (21) arranged for engagement by a corresponding contact (16), such as a roller, attached to the main blade (12) of an air disconnect switch (100). In particular, the actuating arm (21) comprises two rods (22) extending next to each other and adapted for receiving the corresponding contact (16) of the main blade (12) between them. The two rods (22) are movable to alter the distance between them but are biased together by biasing means (24), e.g. helical springs. As the corresponding contact (16) of a main blade (12) will be in engagement with both rods (22) during disconnection and reconnection of the air disconnect switch (100), arcing is thereby prevented. Preferably, the two rods (22) of the UVI (30) are made of aluminium.

Abstract: A switching apparatus comprises: a first current-conductive branch (12) including a first switching element (24), the first switching element (24) configured to be switchable to selectively permit and block a flow of current in the first current-conductive branch (12); a second current-conductive branch (14) including a second switching element (32), the second switching element (32) configured to be switchable to selectively permit and block a flow of current in the second current-conductive branch (14); and first and second terminals (18,20) for connection, in use, to an electrical network (22), wherein the first and second current-conductive branches (12,14) extend between the first and second terminals (18,20), wherein the first current-conductive branch (12) further includes an energy storage element electrically coupled to the second switching element (32) so that the energy storage element is configured as a power source for enabling the operation of the second switching element (32), and the first swi

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 least one 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 c

Abstract: Embodiments of the disclosure include systems and methods for providing an electric high-voltage circuit breaker. In one embodiment, a circuit breaker includes a primary chamber; and a compression chamber, wherein the circuit breaker further includes a valve configured to control a fluid flow between the primary chamber and the compression chamber, wherein the valve includes a valve body, a first valve plate that is arranged axially movable with respect to the valve body, and a second valve plate that is arranged between and movable with respect to the valve body and the first valve plate, wherein said first valve plate includes at least one opening enabling the fluid flow through the first valve plate, wherein a first surface of the valve body forms a valve seat for the first valve plate, and wherein a first surface of the first valve plate forms a valve seat for the second valve plate.