Search results for " tolerance"
showing 10 items of 760 documents
Development of Diagnostic Systems for the Fault Tolerant Operation of Micro-Grids
2010
The progressive penetration level of Distributed Generation (DG) is destined to cause deep changes in the existing distribution networks no longer considered as passive terminations of the whole electrical system. A possible solution is the realization of small networks, namely the Micro-Grids, reproducing in themselves the structure of the main production and distribution of the electrical energy system. In order to gain an adequate reliability level of the micro-grids the individuation and the management of the faults with the goal of maintaining the micro-grid operation (fault tolerant operation) is quite important. In the present paper after the introduction of the aims of several diagn…
A review of multiple faults diagnosis methods in Voltage Source Inverters
2015
This paper examines, as in short review, the methods of diagnosis of simple and multiple faults on Voltage Source Inverter (VSI). The methods examined here are essentially based on the inspection of the load currents. Some of these diagnosis methods are characterized by low computational effort, other for a better reliability avoiding faultless positive tests. Some solutions are characterized by a share of these benefits while others prefer an enforcement of trustworthiness, in spite of the lower calculation amount. The analysis of the technical literature, certainly, offers a glimpse about the creation of new algorithms and significant advances for the future.
A Geometrical Simple Approach for Power Silicon Devices Fault Detection and Fault-Tolerant Operation of a Voltage Source Inverter
2012
Fault-tolerant converters have been widely investigated for years and nowadays an extensive technical literature on this field exists. This paper presents a novel fault detection algorithm based on a simple geometrical approach. In the algorithm analysis both the case of faults in single device and the lose of an entire inverter leg have been considered. False positive detections are avoided by considering a proper number of current samples. The proposed fault detection algorithm is characterized by simplicity, low computational and implementation effort with a consequent enough fast execution, easy control integration with the possibility to use it both in hardware in the loop systems and …
A suitable control technique for fault-tolerant converters in Distributed Generation
2011
The penetration of Distributed Generation (DG) in power systems is deeply changing the existing distribution networks which is becoming a very sophisticated and complex systems incorporating both active (generators) and passive systems (distribution systems, converters and loads). The necessary simplification can be obtained dealing with small networks, namely Micro-Grids, reproducing, in a smaller scale, the structure and the problems of large networks including production, transmission and distribution of the electrical energy. In order to achieve an adequate level of reliability, fault-tolerant operations of micro-grids become very important. This result can be achieved only using power …
Improved Planning In-Service Inspections of Fatigued Aircraft Structures Under Parametric Uncertainty of Underlying Lifetime Models
2014
Certain fatigued structures must be inspected in order to detect fatigue damages that would otherwise not be apparent. A technique for obtaining optimal inspection strategies is proposed for situations where it is difficult to quantify the costs associated with inspections and undetected failure. For fatigued structures for which fatigue damages are only detected at the time of inspection, it is important to be able to determine the optimal times of inspection. Fewer inspections will lead to lower fatigue reliability of the structure upon demand, and frequent inspection will lead to higher cost. When there is a fatigue reliability requirement, the problem is usually to develop an inspection…
A General Mathematical Model for non-Redundant Fault-Tolerant Inverters
2011
Industrial systems able to release trusted services is an integrated concept that resumes the attributes of availability, reliability, safety, integrity, and maintainability. In power electronics this can be aimed via the introduction of fault tolerant architectures. While In the past technical literature the mathematical modeling problem for non-redundant converters was fronted studying separately the cases of fault leg by leg, in this paper a general model able to include the three possible cases of leg faults with a unique set of equation is introduced and discussed. The same model allows to evaluate the DC Link transient and steady state evolution and also allows to develop with much ea…
Flexible power converters for the fault tolerant operation of Micro-Grids
2010
The progressive penetration level of Distributed Generation (DG) is destined to cause deep changes in the existing distribution networks no longer considered as passive terminations of the whole electrical system. A possible solution is the realization of small networks, namely the Micro-Grids, reproducing in themselves the structure of the main production and distribution of the electrical energy system. In order to gain an adequate reliability level of the microgrids the individuation and the management of the faults with the goal of maintaining the micro-grid operation (fault tolerant operation) is quite important. In the present paper flexible power converters and a companion control al…
The Influence of Ambiguity Tolerance on Willingness to Communicate in L2
2018
The main purpose of this chapter is to find empirical evidence for the role of ambiguity tolerance (AT) in shaping one’s L2 willingness to communicate levels in the context of the English-as-a-foreign-language (EFL) classroom, in the Polish educational context. As the pyramid model of L2 WTC proposes (Maclntyre et al„ 1998), AT’s basis is constituted by the most distal and enduring influences of personality. For this reason, ambiguity tolerance, conceived of as a personality variable (Fumham and Marks, 2013), can have a significant impact on L2 WTC. The complexity of interrelated mechanisms embedded in the foreign language learning context induce ambivalent feelings of being simultaneously …
Contamination of a hospital plumbing system by persister cells of a copper-tolerant high-risk clone of Pseudomonas aeruginosa
2019
Abstract Background Pseudomonas aeruginosa (PA) is an important opportunistic pathogen that thrives best in the distal elements of plumbing and waste-water systems. Although nosocomial outbreaks of PA have been associated with water sources, the role of the plumbing system of healthcare premises as a reservoir for this pathogen is still unclear. Materials and methods We collected water samples from 12 technical areas, distant from any medical activity, in a teaching hospital in France once a week for 11 weeks. We used a method that resuscitates persister cells because of the nutrient-poor conditions and the presence of inhibitors (e.g. chlorine and copper ions). Briefly, water was sampled i…
Suppression of humoral antibody formation against sheep red blood cells by infections with HSV-2 and the influence of mouse cytomegalovirus
1987
HSV-2 infections suppress the antibody response to HSV-1 but do not impair the mouse cytomegalo virus (MCMV) antibody generating system. In contrast, the sheep red blood cell (SRBC) IgM response is impaired by preinfections with HSV-2 but not with HSV-1. From the time kinetics of this suppression it can be concluded that only a certain submechanism "spills over" to the SRBC system. MCMV suppresses the antibody formation induced by HSV-1.