Abstract: A circuit-breaker device, comprising a main branch and an auxiliary branch electrically in parallel with the main branch, wherein the main branch comprises at least one mechanical switch-disconnector in series with a breaker cell constituted of at least one semiconductor switch, and a snubber circuit in parallel with the at least one breaker cell, the snubber circuit including an energy storage element, wherein the mechanical switch-disconnector is switchable to selectively allow current to flow in the main branch in a first mode of operation or commutate current from the main branch to the auxiliary branch in a second mode of operation, characterized in that the snubber circuit further comprises a bleeder resistor arranged to create a counter current in the main branch when current is commutated from the main branch to the auxiliary branch by discharging the energy storage element.

Abstract: A switching valve includes series-connected switching elements and auxiliary circuits. Each auxiliary circuit is connected in parallel with a respective one of the series-connected switching elements. Each auxiliary circuit includes a respective auxiliary capacitor. The method includes carrying out a compensation procedure. The compensation procedure includes: initiating a turn-off event by sending a respective turn-off control signal to each switching element; measuring a respective capacitor voltage value of each auxiliary capacitor after the turn-off event; comparing the measured capacitor voltage values; and using the comparison between the measured capacitor voltages as a reference to adjust the time of sending a or a respective turn-off control signal to at least one of the switching elements so as to reduce a or a respective time difference between the turn-off times of the switching elements at the next turn-off event.

Abstract: The present disclosure relates to a pulverizer includes a pulverizer housing with an grinding assembly having a grinding table situated therein. The grinding table provides a grinding surface area for a material, such as a fossil fuel, such as coal, to be pulverized. The grinding table is mounted on a gearbox shaft operatively connected to a gearbox drive mechanism so as to be capable of driven rotation within the pulverizer housing. A journal assembly having a journal head and the journal assembly and a spring assembly are mounted on the pulverizer housing so that the journal head engage the spring assembly.

Abstract: The open-phase condition of a standby power transformer is detected by monitoring functions of the phase currents. The functions have parameters calculated based on reference currents, which constitute a “fingerprint” when all the phases are connected.

Abstract: There is disclosed a controller (112) for a power electronic network element (110) of a power transmission network (100), wherein the controller (112) is configured to vary a control parameter of the network element (110) which at least partly determines a ripple profile in a transmission line of the network. The controller (112) is configured to vary the control parameter between at least a first value and second value to cause the ripple profile in the transmission line to change; and the controller is configured to vary the control parameter periodically or in response to a signal indicating a threshold temperature at a hotspot location along the transmission line. A method of optimising control parameters for a power transmission network (100) is also disclosed.

Abstract: A system for removing impurities from post-combustion gas includes an oxidizer and a reducer operatively connected to the oxidizer, the reducer configured to receive the post-combustion gas. The system further includes a CLOU material capable of selective circulation between the oxidizer and reducer. The CLOU material further oxidizes impurities present in the post-combustion gas to reduce or remove the same.

Abstract: In the field of voltage assemblies with a charge storage capability for use in high voltage direct current converters there is provided a corona shield. The corona shield includes a peripheral frame which is formed from one or more frame members and within which lies a frame aperture. The corona shield also includes a barrier member that is fixedly secured to the peripheral frame. The barrier member extends across and occludes the frame aperture to inhibit bodily ingress through the frame aperture.

Abstract: A method of assembling a heat exchanger includes the steps of fluidly connecting a plurality of first heat exchanger tubes to a first connecting tube portion at an assembly location to form a first subassembly, fluidly connecting a plurality of second heat exchanger tubes to a second connecting tube portion at the assembly location to form a second subassembly, transporting the first subassembly and the second subassembly from the assembly location to an installation location, and connecting the first subassembly to the second subassembly at a single connection point between the first connecting tube portion and the second tube connecting portion.

Abstract: In the field of high voltage direct current (HVDC) power transmission there is provided a power converter assembly (10) comprising a line-commutated power converter (12) that is configured to transfer power from a DC network (14) to a corresponding receiving AC network (16). The power converter assembly (10) also includes a control unit which is operatively associated with the line-commutated power converter (12) and is programmed, in response to the receiving AC network (16) exhibiting a reduced AC voltage (Va, Vb, Vc), to cause a reduction in the operating DC voltage (VDC) of the line-commutated power converter (12) by the DC network (14).

Abstract: The method for managing a shut down of a boiler having a duct and heat exchanging components is provided. The heat exchanging component having tubed heat exchanging surfaces within the duct and headers outside the duct. The method includes regulating the temperature of the headers during shut down to a temperature close to the one expected for the steam moving from the tubed heat exchanging surfaces into the headers at a starting up following the shut down.

Abstract: A method and a facility for filling a high- or medium-voltage gas-insulated electrical apparatus in which the insulating gas comprises a mixture of heptafluoroisobutyronitrile ((CF3)2CFCN) and carbon dioxide. The method and the facility using a mixture of (CF3)2CFCN and CO2 in pressurised liquid form which is heated to a temperature no lower than the critical temperature of the mixture.

Abstract: Moisture separator configuration for separating water droplets from steam of a flow having a mixture of steam and water droplets, such that the cited flow travels through the moisture separator configuration so that this separation is achieved. The moisture separator configuration includes a plurality of plates oriented in line with the flow. The plurality of plates form channels through which the flow travels. The channels have progressive cross section variation along the flow direction, in order to collect progressively the water droplets separated from the steam in the flow.

Abstract: A device for actuating a rotating shaft selected from a plurality of parallel rotating shafts, comprising a driving shaft supported and actuated by corresponding rotation means, which is provided with a driving gear for the transmission of torque, a plurality of driven shafts each one of which is provided with a corresponding driven gear that is designed to be meshed with the driving gear, the driven gears being arranged on the respective driven shaft in an axial position that is offset with respect to the other driven gears, the driving gear being capable of performing a translational movement axially with means of translational motion for alternate meshing with one of the driven gears, the device further comprising means of prevention of rotation for the driven shafts whose driven gear is not meshed with the driving gear.

Abstract: A method and apparatus for controlling a fault blocking voltage source converter apparatus which is, in use, connected to an AC system and a DC system for power transmission, in the event of a DC side interruption operating the voltage source converter apparatus after identification of a need for a DC side interruption based on a voltage order, so as to extract at least some electrical energy stored in the connected DC system to the voltage source converter apparatus.

Abstract: A voltage source converter comprises a converter arm extending between two terminals each terminal being connectable to a or a respective electrical network, the converter arm including a valve that includes at least one module, the or each module being operable to selectively provide a voltage source; and a controller programmed to selectively operate the valve to clamp a voltage at either or both of the two terminals and thereby operate the valve as a current limiter to limit a selected current flowing in the converter arm at or below a fixed or variable current threshold.

Abstract: A dissimilar metal connection arrangement comprising a dissimilar metal connection between a first member made of a first metal and having a first end, and a second member made of a second metal different from said first metal with regard to its metallurgical behavior, and having a second end, wherein the first end of the first member is fixedly connected to the second end of the second member. An increased lifetime of the connection is achieved by arranging a heating means at said dissimilar metal connection for controlled heating of said dissimilar metal connection.

Abstract: A boiler includes an enclosure having at least a supply for fuel and oxidizer and at least a supply for a SNCR reagent. The supply for the SNCR reagent includes at least a regulation valve for the SNCR reagent. The boiler includes at least a sensor for measuring information indicative of the NOx concentration over at least one given enclosure cross section. The boiler includes a controller connected to the at least a sensor and to the at least a regulation valve. The controller regulates the SNCR reagent supply according to the measured information indicative of the NOx concentration.

Abstract: The invention relates to a drive rod for driving a movable contact element of a high-voltage switching device, wherein said drive rod comprises a first section for connecting said drive rod to a drive mechanism, a second section for connecting said drive rod to said movable contact element, and an intermediate section between said first section and said second section, characterized in that said intermediate section comprises coupling means for rotatably coupling said first section to said second section.

Abstract: A top head housing for a current transformer, mounted on top of an insulating column of the current transformer, and forming a chamber for windings of the current transformer, the top head housing being made of two parts fixed one to the other, and including two openings through each of which a conductor penetrates the chamber, the openings being symmetrically opposed with reference to a main vertical axis of the top head housing, wherein the two parts of the top head housing consist of two half shells including identical bodies.

Abstract: A circuit breaker including a stationary frame, at least a pair of arc contacts, an actuation rod, a compression chamber in which a portion of the dielectric gas is compressed; a cylinder and a piston connected with the rod, which are movable within the stationary frame along main axis, for compressing the portion of the dielectric gas in the compression chamber; a link mechanism connecting the piston to the rod, wherein the stationary frame includes a cylindrical portion with which each of the piston and of the cylinder are radially in gastight contact and which bounds the compression chamber together with the piston and the cylinder.