Abstract: The present invention relates to an on-load tap changer control method for a power excitation chain. The chain includes a generator, a step-up transformer equipped with an on-load tap changer and connected on the one hand to the output of the generator and on the other hand to a transmission bus, and an excitation control system with a generator automatic voltage regulator (AVRG) and one excitation limiter (OELG, UELG). The method monitors the excitation conditions of the generator, activates the one excitation limiter (OELG, UELG) when the monitored excitation conditions are outside a predefined range, and temporarily inhibits the change of step of the on-load tape changer.

Abstract: In an excitation device for stators of generators for high-induction measurement, the greatest possible compensation of the reactive power requirement is achieved. Depending on the size and energy requirement of the generator, a number of individual excitation modules with a corresponding number of individual excitation windings are provided, wherein a minimum necessary total excitation current can be supplied by superimposing the individual currents of the excitation windings.

Abstract: A seal arrangement is installed between confronting co-planar portions of a low pressure steam turbine exhaust hood and a circular bulkhead that forms part of an exhaust duct structure of a steam turbine module. The seal arrangement forms a vacuum seal between the interior and exterior of the exhaust hood and comprises a flexible gasket in the form of an annular diaphragm. This diaphragm has a radially inner circumferential portion that seals with the bulkhead, a radially outer circumferential portion that seals with the exhaust hood, and a radially median resilient portion. Sealing is achieved by providing radially inner and outer clamping flanges operative to sealingly clamp inner and outer circumferential portions of the gasket to the bulkhead and the exhaust hood respectively.

Abstract: The invention concerns energy delivery system and method for a gate drive unit controlling a thyristor-based valve (19). The system comprises at least one current transformer (22) located in the main current path of the valve.

Abstract: A burner system with staged fuel injection includes at least one burner with a mixing zone. A combustion chamber is disposed downstream of the mixing zone and a first fuel introduction device is provided upstream of the mixing zone. Furthermore, a second fuel introduction device for the direct injection of fuel into the combustion chamber, is disposed downstream of the mixing zone. In addition, at least one sensor for determining combustion parameters is connected to a control device. The control device is designed to control the second fuel introduction device as a function of the parameters determined by the sensors.

Abstract: A voltage source converter includes a converter limb having limb portions separated by an AC terminal and extending between DC terminals, each limb portion including a primary switching element to switch the limb portion into and out of circuit. The converter further includes an auxiliary limb. The primary switching element of each limb portion is switchable to switch the auxiliary limb into and out of circuit with the corresponding limb portion. The converter further includes a control unit to, in one mode, inject a circulation current that flows in one direction in one of the limb portions and minimize a current flowing in the opposite direction in that limb portion. Each primary switching element switches the respective limb portion into or out of circuit following the minimization of the limb portion current by the circulation current.

Abstract: The combustion device according to the invention produces gases containing CO2 and water vapor and comprises a circulating fluidized bed reaction chamber (1, 2), a separator (10, 20), heat recovery means of which a part is situated in a dense fluidized bed (12, 12a, 22), wherein the part located in the bed of the heat recovery system(s) is composed of catalyst tubes (120, 120a, 220) through which a gas mixture flows. The gas mixture is composed of natural gas and/or naphtha or refinery gas or two or more of these gases. The gas undergoes reformation which converts it into a synthesis gas containing hydrogen. The fact of the catalyst tubes being situated in the dense fluidized bed made up of ashes from the combustion allows the catalyst to be reheated in a homogenous manner and the reforming reaction of the natural gas mixture to be stimulated.

Abstract: An evaporator for steam generation is presented. The evaporator includes a plurality of primary evaporator stages and a secondary evaporator stage. Each primary stage includes one or more primary arrays of heat transfer tubes, an outlet manifold coupled to the arrays, and a downcomer coupled to the manifold. Each of the primary arrays has an inlet for receiving a fluid and is arranged transverse to a flow of gas through the evaporator. The gas heats the fluid flowing through the arrays to form a two phase flow. The outlet manifold receives the two phase flow from the arrays and the downcomer distributes the flow as a component of a primary stage flow. One or more of the plurality of primary evaporator stages selectively form the primary stage flow from respective components of the two phase flow, and provide the primary stage flow to inlets of the secondary evaporator stage.

Abstract: A method for controlling at least one operational parameter of a plant (1) having a combustion unit (3) can include estimating a status of at least one operational variable of the plant to identify an estimated value for the operational variable. For each operational variable, the estimated value for the operational variable can be compared with a measured value of the operational variable to determine an uncertainty value based on a difference in value between the measured value and the estimated value for the operational variable. A control signal can be generated based on a reference signal, the measured value, and the deviation value for sending to at least one element of the plant (1) for controlling a process of the plant (1).

Abstract: An air quality control system (AQCS) useful for processing a gas stream, such as a flue gas stream emitted from a fossil fuel fired boiler, for at least partial removal of acidic and like pollutants therefrom. The air quality control system includes a CDS reactor useful using a reducing agent slurry.

Abstract: A strip seal and method of configuration thereof for sealing portions of components of a gas turbine exposed to pressure pulsations. The strip seal has a sealing face that is configured to follow the contours of first portions of the components. The strip seal further has a pressure face that has a sinusoidal curvilinear shape with respect to the sealing face. The pressure face is configured to prevent localized movement of strip seal by configuring pressure face on its first side to contact sealing face at a plurality of points, on its second side to contact second portions of the components at a plurality of points.

Abstract: A protection device for providing protection against the particles generated by an electric arc when a first electrically conductive part and a second electrically conductive part of an electrical connection unit are separated from each other, the protection device including at least one protection element disposed in the proximity of the place at which the first part and the second part separate in order to form a shield against the particles.

Abstract: A rotating machine cooled by a cooling medium directed through the rotating machine in a main flow and a secondary flow includes a rotor. A stator includes a swirl passage configured to guide the secondary flow so as to be discharged from a pre-swirl nozzle. At least one control device includes a shape-memory alloy disposed in an area of the pre-swirl nozzle and is configured to control the secondary flow based on a temperature in an automated manner.

Abstract: A current limiter for selectively limiting a rate of change of current in a DC electrical network may include a first electrical block including an inductive element and a second electrical block including a bidirectional switch. The first electrical block is connected in parallel with the second electrical block between first and second terminals, and the first and second terminals are connectable to the DC electrical network. The bidirectional switch is switchable to: (1) a first mode to permit current flow through the second electrical block in a first current direction and at the same time inhibit current flow through the second electrical block in a second, opposite current direction; and (2) a second mode to permit current flow through the second electrical block in the second current direction and at the same time inhibit current flow through the second electrical block in the first current direction.

Abstract: A method and apparatus are disclosed for operating a combustion device during a transient operation. The combustion device is fed with at least a fuel. The transient operation includes a period having a period length (T) during which the fuel is fed in an amount lower that a designated (e.g., critical) amount (Mc). A limit value (L) is defined for the period length (T), and fuel feed is regulated to keep the period length (T) smaller or equal to the limit value (L).

Abstract: A damping device for reducing pressure oscillations in a combustion system includes at least a portion provided with a first, outer wall, a second, inner wall, an intermediate plate interposed between the first wall and the second wall. This intermediate plate forms a spacer grid to define at least one chamber between said first wall and said second wall, first passages connecting each of said at least one chamber to the inner of the combustion system, and second passages connecting each of said at least one chamber to the outer of the combustion system. The second passages open at the same side of said chambers as the first passages, the second passages have a portion extending parallel to the inner wall. This parallel portion of said second passages is equipped with heat transfer enhancing means.

Abstract: A wall structure is provided with noise damping insulation properties, for an air intake manifold of a gas turbine. The wall structure includes a first structure for mechanically supporting an outer sheet, which separates the spaces on both sides of the wall in an airtight manner, and further includes a second structure for establishing noise damping insulation between the spaces on both sides of the wall. The second structure is secured to the first structure. A gas turbine including the wall structure is also provided.

Abstract: A gas-insulated substation having an enclosure filled with dielectric gas under pressure, comprising one electrical conductor (1) designed to be live that is of longitudinal axis (X) and placed inside the enclosure (6), and two grading shields (10, 12) surrounding in part the conductor (1), at least one of the grading shields (10) comprising a hollow electrically conductive body (14) of longitudinal axis that is substantially coaxial with the axis of the casing (6), said body (14) comprising an annular depression (22) in its outer surface and orifices (26) passing through said body (14) made in a bottom of said annular depression. Said orifices (26) ensure that the dielectric gas flows between an inside zone and a zone that is outside the grading shield (10) by convection exchange.

Abstract: A method of managing energy supply in which an aggregator receives an energy demand from at least one operator of an energy distribution network and sends instructions to a plurality of energy facilities suitable for providing energy in order to satisfy the demand, the method being characterized by the following steps: each energy facility transmits to the aggregator a description of instantaneous variations of the energy state and technical constraints linked to its operation in order to satisfy the demand; and the aggregator defines in automatic manner for each energy facility a response profile for the demand as a function of the description by taking into account non-linear responses and energy state history data from each energy facility, and transmits the response profile of the energy distribution network to the operator, and transmits a set of control signals to each energy facility in order to satisfy the demand.

Abstract: An exemplary sequential combustor arrangement includes a first burner, a first combustion chamber, a mixer for admixing a dilution gas to the hot gases leaving the first combustion chamber during operation, a second burner, and a second combustion chamber arranged sequentially in a fluid flow connection. The mixer includes at least three groups of injection tubes pointing inwards from the side walls of the mixer for admixing the dilution gas to cool the hot flue gases leaving the first combustion chamber. The first injection tubes of the first group have a first protrusion depth, the second injection tubes of the second group have a protrusion depth, and the third injection tubes of the third group have a third protrusion depth.