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.

Modified voltage source converter structure

Abstract: The invention concerns a voltage source converter (26) comprising a group of phase legs, at least three connection terminals (AC1, AC2, AC3, DC+, DC-) for connecting the phase legs to power transmission elements, a first group of cells (C1p1, C2p1, C1n1, C2n1, C1p2, C2p2, C1n2, C2n2, C1p3, C2p3, C1n3, C2n3) ineach phase leg and a second group of cells (C3p1, C3n1,C3p2, C3n2 C3p3, C3n3). The cells (C1p1, C2p1, C1n1, C2n1, C1p2, C2p2, C1n2, C2n2, C1p3, C2p3, C1n3, C2n3) in the first group are only capable of providing unipolarvoltage contributions to the converterand connected for only being capable of such unipolar voltage contributions, while the cells (C3p1, C3n1,C3p2, C3n2 C3p3, C3n3) in the second group are connected to the corresponding cells of the first group and arranged to have bipolar voltage contribution capability.

Integration of large wind farms into utility grids pt. I - Modeling of DFIG

Abstract: In this part of the paper the authors describe a newly developed model for double-fed induction wind generators (DFIC) that is suitable for transient stability studies. In this model the main performance characteristics of DFIG are included. The model is validated against a more detailed EMTP-level model of such generation. The results suggest that the stability model has sufficient accuracy for representation of the electromechanical dynamics of interest in simulation studies for identifying critical operating conditions. Further analysis of these critical conditions may require the use of more detailed EMTP-level models.

Sando: an extensible local code search framework

Abstract: Developers heavily rely on Local Code Search (LCS)---the execution of a text-based search on a single code base---to find starting points in software maintenance tasks. While LCS approaches commonly used by developers are based on lexical matching and often result in failed searches or irrelevant results, developers have not yet migrated to the various research approaches that have made significant advancements in LCS. We hypothesize that two of the major reasons for this lack of migration are as follows. First, developers do not know which approach is the best, due to a lack of comparative field studies and the discrepancies in the underlying LCS process that these research approaches address. Second, developers lack access to a stable implementation of most of the research approaches. To address these issues, we studied a number of LCS approaches, distilled the general component structure underlying these approaches and, based on this structure, developed a LCS tool and framework, called Sando. Currently used by developers at ABB, Inc. and elsewhere, Sando also supports the flexible extension of its components to rapidly disseminate research advancements, and allows for user-based evaluation of competing approaches.

Method and control system for scheduling load of a power plant

Abstract: The present invention relates to a method for optimizing load scheduling for a power plant having one or more generation units. The method comprises the steps of analyzing the operating state of one or more components of generation units in terms of one or more risk indices associated with one or more components of generation units; updating the objective function that reflects the state of one or more components of generation units; solving the objective function to optimize schedule of the one or more generation units and operating state of one or more components of generation units; and operating the one or more generation units at optimized schedule and operating state. The invention also relate to a control system for scheduling load of a power plant having one or more generation units. The control system comprises an optimizer having a single objective function for optimizing load scheduling which includes maintenance scheduling and for optimally controlling processes of the one or more generation units. The optimizer utilizes a plant model component and a failure model component for load scheduling optimization.

An analysis of an implantable dosimeter system for external beam therapy.

Abstract: Background and Purpose: To review the data from an implantable radiation dosimetry system used in a clinical setting and to examine correlations between dosimeter readings and potential causative error sources. Materials and Methods: MOSFET (metal oxide semiconductor field effect transistor) based encapsulated dosimeters were evaluated in a phantom ( in vitro ) and in a study with 18 patients. The dosimeters were placed in the gross tumor volume or in collateral normal tissue. Predicted dose values were established by imaging the dosimeters in the planning CTs. Results: The in vitro study confirmed that bounding cumulative errors due to setup, planning, and machine output within a ±5% level is achievable. In patients, it was found that deviations from the targeted dose often exceeded the 5% level. Conclusions: The use of an implantable dosimeter system could provide an effective empiric check on the dose delivered at depth. Such a tool may have value for institutional quality assurance, as well as for therapy delivered to individual patients.