Abstract: The present invention relates to an on-load tap changer control method for a power transformer in a power system. The power transformer has a primary side for a connection to a first grid in which electric power is generated, and a secondary side for connection to a second grid in which electrical power is consumed, the power transformer being equipped with an on-load tap changer. The method includes measuring the voltage and current at least on the primary side (u1, i1) or on the secondary side (u2 i2) of the power transformer, processing said measured voltages (u1; u2) and currents (i1; i2) in order to derive prospective reactive power at the output of the power transformer after prospective tap-change, comparing prospective reactive power to a predefined set-point, and—initiating tap-change of on-load tap changer if prospective reactive power is closer to said predefined set-point than actual reactive power.

Abstract: A power plant with a fossil fuel fired boiler, an air feed system, flue gas system and condensate system. A unitary flue gas heat exchanger spans a bypass line in the flue gas system and the condensate system so as to improve the thermal efficiency of the power plant while minimising complexity.

Abstract: A solar thermal power system includes a solar receiver, and a thermal energy storage arrangement having thermal energy storage fluid to be circulated through the solar receiver to store thermal energy. The system includes a multistage steam turbine operable on variable pressure steam generated by a steam generator arrangement, by utilizing the thermal energy storage fluid. The arrangement includes an economizer section, an evaporator section, and a superheater section communicably configured to utilize the heat of the hot thermal energy storage fluid to generate and supply the variable pressure steam to the turbine. The system includes a recirculation line configured around the economizer section to recirculate the heated water to an inlet of the economizer section, increasing pressure range of the variable pressure steam in the arrangement.

Abstract: The invention relates to an assembly of modules for an electrical circuit comprising: a module support for at least two modules and at least two modules, each module comprising two complementary connectable sub-modules. The module support comprises for each sub-module at least an alignment member adapted to individually align the sub-module during its installation on the module support in such way to connect it to complementary sub-module already installed on the module support to form one of the modules. The invention also relates on a module support, a module and a Flexible Alternative Current Transmission Systems.

Abstract: A solar receiver configuration (receiver) adapted to include a plurality of receiver heat transfer passes. Each pass includes a plurality of panels. Further, each panel includes a plurality of tubes, tangentially arranged, vertically extending between horizontally placed lower and upper headers. The headers, which are pipe assemblies with closed ends, of adjacent panels are horizontally and vertically offset one to another to form a substantially continuous tube surface. Such continuous tube surface enables solar heating of the fluid flow therefrom in at least a parallel flow arrangement and a serpentine flow arrangement.

Abstract: A solar thermal power system includes a solar receiver for heating thermal energy storage fluid to be stored and utilized from a thermal energy storage arrangement having hot and cold storage tanks. The system includes a steam generator arrangement, which utilizes the heat of the thermal energy storage fluid to produce steam to run a turbine. The arrangement includes a bypass line configured to bypass the hot storage tank from the steam generator arrangement, and to supply the hot thermal energy storage fluid from the solar receiver directly to the steam generator arrangement, during day times, when the solar receiver the steam generator arrangement are both in operating mode, thereby recovering stored potential energy available in the down corner hot thermal energy storage fluid from the solar receiver.

Abstract: A merging unit for substation automation includes at least one input interface for receiving input data characterizing at least one voltage and/or current related to a component of a power system, and a timing synchronization mechanism which includes an interface to an external synchronization network operating according to one of Inter Range Instrumentation Group, IRIG, -B standard, the 1PPS standard and the Institute of Electrical and the Electronics Engineers, IEEE, 1588 standard. The merging unit is configured to implement logical nodes according to the International Electrotechnical Commission, IEC, 61850-7 standard. The merging unit is configured to map information to and/or from at least one of the logical nodes; to the IEC 61850-9-2 sampled measured values, SMV, communication protocol.

Abstract: A solar thermal power system can include a solar receiver steam generator, a thermal energy storage arrangement utilizing a thermal energy storage fluid, and a multistage steam turbine for driving an electrical generator to produce electrical power. The solar thermal power system has a first operating mode in which steam is generated by the solar receiver steam generator and is supplied both to the thermal energy storage arrangement and to a high pressure turbine inlet of the multistage steam turbine. In a second operating mode, steam is generated by recovering stored thermal energy from the thermal energy storage fluid of the thermal energy storage arrangement for injection into the multistage steam turbine at a location or turbine stage downstream of the high pressure turbine inlet.

Abstract: A solar boiler 300 includes first and second primary receiver panels 500, 600 spaced apart by a gap 700. Each panel 500, 600 include a plurality of primary boiler tubes 510, 610 for receiving solar flux. The boiler 300 includes at least one secondary receiver arrangement 800 disposed across the gap 700 for receiving solar flux incident thereacross. The arrangement 800 includes at least one secondary boiler tube 810, and at least one support member 820 supported thereto. The arrangement 800 is configured relative to the primary panels 500, 600 such that endmost primary boiler tubes 510a, 610a are supported over the support member 820 in spaced relation ‘S’ to the secondary boiler tube 810 for enabling transverse and lateral thermal expansion of the tubes 510, 610, 810 without bending out. Further, a panel joining attachment 900 is provided for attaching the panels 500, 600 and the arrangement 800.

Abstract: The molten salt solar tower system 100 is provided for controlling molten salt temperature in a solar receiver 130 for effective operation of the system 100 while without degrading physical properties of molten salt. The system 100 includes two circuits, first 140 and second 150. The first circuit 140 is configured to supply relatively cold molten salt in the solar receiver 130 for heating, and the second circuit 150 is configured to supply a predetermined amount of the relatively cold molten salt in the first circuit 140, as and when the temperature of the relatively hot molten salt circulating through the solar receiver 130 exceeds a predetermined set temperature value thereof.

Abstract: A solar thermal power plant comprises a solar radiation receiver mounted on a tower surrounded by a heliostat field to receive solar radiation reflected by heliostats. A power generation circuit includes a steam turbine for driving an electrical generator to produce electrical power, and water in the power generation circuit is heated directly by solar radiation reflected onto the solar radiation receiver by the heliostat field to generate steam to drive the steam turbine. An energy storage circuit includes a thermal energy storage fluid, such as molten salt, which is capable of being heated directly by solar radiation reflected by the heliostat field. A heat exchanger is also provided for recovering thermal energy from the thermal energy storage fluid. The recovered thermal energy may then be used to generate steam to drive the steam turbine.

Abstract: A head assembly for a pulverized coal nozzle includes removeable wear-resistant inserts having vanes. The vanes may be flat or curved to direct a stream of air and pulverized solid fuel particles from the inlet port toward the outlet port. The curved vanes curve in two dimensions to evenly distribute the stream of air and pulverized solid fuel away from the outer surfaces reducing wear and corrosion. The pipe elbow has a removable cover that allows for easy access. The vanes are attached to a wear-resistant replaceable liner thus allowing them to be easily removed and replaced. The wear-resistant liner may be made from several parts for ease of removal and replacement.

Abstract: A method of determining a communication time delay in a communication network between a local terminal and one or more remote terminals within an electrical power network includes: selecting, in respect of the or each remote terminal a calculation node in the electrical power network; calculating respective node currents flowing into the corresponding calculation node from the local terminal and the or each remote terminal; equating, in respect of the or each remote terminal, a sum of node currents flowing into the corresponding calculation node to zero according to Kirchhoff s first law; and extracting, in respect of the or each remote terminal, a communication time delay between the local terminal and the said respective remote terminal from a corresponding equated sum of node currents.

Abstract: An AC/DC electrical converter device having a source mode and a recovery mode, and for connection, on the AC side, to an AC voltage source and, on the DC side, to a DC power distribution network. It includes an AC/DC converter, a switching cell with two switches (K1, K2) that are bidirectional for current, the switches sharing a common point (A) and each having a respective end terminal (B1, B2), a filter stage, and a control unit for the cell; the converter is for connection on the AC side to the voltage source and is connected on the DC side to the cell; in use, the first switch (K1) is connected between the converter and the DC power distribution network via the filter stage, the second switch (K2) forming a combination in parallel with the filter stage and the DC power distribution network. The control means are able to manage a short-circuit current in source mode by operating on the first and second switches.

Abstract: A DC to DC converter assembly, for connecting first and second high voltage DC power transmission networks, comprising first and second modular multilevel converters, each converter including a first converter limb having first and second limb portions, each limb portion including a least one module switchable to selectively provide a voltage source and thereby vary the magnitude ratio of a DC voltage (V1, V2) across the first and second terminals of a respective converter and an AC voltage (VAC) at the third terminal of the corresponding converter, the DC to DC converter assembly further including a first link electrically connecting the third terminal of one converter, with the third terminal of the other converter, and at least one converter further including a controller configured to switch the first and second limb portions in the first converter limb of the said converter into simultaneous conduction to divert a portion (IDiV1) of current flowing within the said converter away from the first link.

Abstract: The invention relates to a method of controlling switchgear in order to estimate the remanent flux value of a power transformer during disconnection from a high-voltage electrical network using voltage measurements delivered by a capacitive voltage transformer by correcting the transfer function of the capacitive voltage transformer, and in which said value is delivered to a controller that determines the optimum switchgear switching instant.

Abstract: A solar thermal power system includes a solar receiver and a thermal energy storage arrangement including thermal energy storage fluid to be circulated through the solar receiver to store thermal energy. The system includes a multistage steam turbine operable on variable pressure steam generated by primary and secondary arrangements, by utilizing the fluid. The primary arrangement generates and supplies a high pressure steam to a high pressure turbine inlet, and exits from a high pressure turbine outlet. The secondary arrangement having a reheat assembly, to generate an intermediate pressure steam from the fluid, received from the storage arrangement through the reheat assembly. The intermediate pressure steam and released steam from a high pressure turbine outlet are mixed and reheated in the reheat assembly to be supplied to an intermediate pressure turbine inlet.

Abstract: A power electronic converter for use in high voltage direct current power transmission and reactive power compensation comprises a plurality of switching elements interconnecting in use a DC network and one or more AC networks, the plurality of switching elements being controllable in use to facilitate power conversion between the AC and DC networks, wherein in use, the plurality of switching elements are controllable to form one or more short circuits within the power electronic converter so as to define one or more primary current flow paths, the or each primary current flow path including a respective one of the AC networks and the power electronic converter and bypassing the DC network.

Abstract: A DC-to-DC converter assembly includes an inverter having first and second terminals connectable to a power transmission network. The inverter has a modular multilevel converter including a first inverter limb extending between the first and second terminals with first and second inverter limb portions separated by a third terminal. Each inverter limb portion includes at least one rationalized module having first and second sets of series-connected current flow control elements connected in parallel with an energy storage device. The current flow control elements include an active switching element directing current through the energy storage device and a passive current check element limiting current flow to one direction. The current flow control elements and energy storage device provide a voltage source to synthesize an AC voltage at the third terminal. A rectifier is electrically connected to the third terminal and connectable to a second power transmission network.

Abstract: The present invention relates to an method for producing sodium carbonate by integration of a carbon dioxide capture process with an ammonia-soda process. The present invention moreover relates to a plant for producing sodium carbonate comprising a carbon dioxide capture system and an ammonia-soda system. Uses of fluid streams generated in a carbon dioxide capture process in an ammonia-soda process is moreover disclosed.