ABB Ltd

About: ABB Ltd is a company organization based out in Zurich, Switzerland. It is known for research contribution in the topics: Voltage & Signal. The organization has 6222 authors who have published 6852 publications receiving 83994 citations.

Method for operating a gas turbine group with catalytic gas generator

Abstract: In the case of a method for operating a gas turbine group, the gas turbine group essentially consists of a compressor (1), a combustion chamber (5), a turbine (2) and a generator (3). Fuel is mixed in a premixer (18) of the combustion chamber (5), prior to the combustion, with air compressed in the compressor (1), and subsequently burned in a combustion space (19). Compressed air, fed via an air line element (15) , is mixed with fuel fed via a fuel line element (16) and delivered to a reactor (10) having a catalytic coating. The air/fuel mixture is converted in the reactor (10) into a synthesis gas comprising hydrogen, carbon monoxide, residual air and residual fuel and this synthesis gas is injected into the zones of the combustion chamber (5) where the flame is stabilized.

Device for measuring gas density

Abstract: The device serves to measure the density of a gas, in particular of the insulating gas of a gas-insulated electrical installation. It contains two resonators (11, 12) each comprising a piezoelectric crystal (14, 15) and each comprising two electrodes applied to the crystal. A first (11) of the two resonators (11, 12) is mounted in a first chamber (5) containing the gas to be measured, whereas a second (12) is mounted in a second chamber (6) sealed with respect to the gas. Despite small dimensions and despite simple and robust construction, this device is intended to have a high measurement precision over a long period of time. This is achieved by drawing the two resonators (11, 12) from a multiplicity of similar resonators manufactured by mass production and not subjected to a frequency alignment. The first resonator (11) is unaltered with respect to the manufacture in mass production. The second resonator (12) is likewise unaltered with respect to the manufacture in mass production and, under vacuum and with equality of temperature, it has the same resonance frequency as the first resonator (11) within a specified frequency tolerance. The second resonator (12) may, however, also be modified, by altering its electrodes (18, 19), in such a way that, under vacuum and with equality of temperature, it has the same resonance frequency as the first resonator (11) within the specified frequency tolerance.

Arrangement for and method of cooling a wall surrounded on one side by hot gas

Abstract: An arrangement and method for cooling a wall surrounded on one side by hot gas, for example, a guide blade of a turbine, where cooling air is directed into a space between the wall and a cooling insert wall, and allowed to flow through rows of holes in the wall to an outer surface of the wall. A rib is arranged upstream of the row of holes on the inner surface of the wall, and the cooling insert wall is shaped to bulge toward the wall at the hole location, so that a guiding surface parallel to an entry angle of the holes is provided. By causing the cooling air to flow in the entry angle of the holes before it reaches the holes, the cooling air forms stable inner-vortex pairs in the flow, and entry losses are reduced. Cooling air not flowing into a first row of holes is accelerated and guided past spacers and pins in the space, before being guided to downstream rows of holes.

A hybrid distribution transformer with ac & dc power capabilities

Abstract: A hybrid transformer is provided that includes an electromagnetic transformer and an AC-AC converter with a DC bridge. The AC-AC converter is operable to keep the input voltage and current of the hybrid transformer substantially in phase and to reduce fluctuation in the output voltage of the hybrid transformer in the event of an increase or decrease in the input voltage.

Method and arrangement for tracking the maximum power point of a photovoltaic module

Abstract: A method and apparatus of tracking the maximum power point of a photovoltaic module. The method includes measuring an output voltage of the photovoltaic module, determining an output voltage of the inverter connected to the photovoltaic module, and measuring output current of the inverter connected to the photovoltaic module. A variable relating to energy of the capacitor is defined using the measured PV module output voltage, and a second harmonic component is extracted from the defined variable. A second harmonic component of the module output power is estimated using the defined variable, measured output current of the inverter, and the determined output voltage of the inverter. The estimated and extracted second harmonic components are multiplied, and a DC component is extracted from the product. A control signal for controlling the inverter connected to the photovoltaic module is formed by using the extracted DC component in a PI algorithm.