Wyniki wyszukiwania - BazTech

1

Distance protection operation during earth-faults in high voltage networks with cable inserts

Duda Dominik, Maźniewski Krzysztof, Witek Bernard

Przegląd Elektrotechniczny

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2023

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R. 99, nr 6

97--101

EN

Selected problems occurring in distance protection systems during earth faults in high voltage overhead cable lines (HV) were analyzed. The Alternative Transients Program (ATP) environment was used to simulate and model the phenomena. The influence of such factors as: fault location, arrangement of HV cables in the excavation, configuration of the return conductors and the earthing resistance of the return conductors was analyzed. The obtained results make it possible to verify the criteria for detecting earth faults in HV networks.

PL

Przeanalizowano wybrane problemy występujące w układach zabezpieczeń odległościowych podczas zwarć doziemnych w liniach napowietrzno-kablowych wysokiego napięcia (WN). Do symulacji i modelowania zjawisk wykorzystano środowisko Alternative Transients Program (ATP). Zbadano przebiegi prądów i napięć fazowych, składowe symetryczne prądu oraz położenie fazorów impedancji doziemionej fazy. Przeanalizowano wpływ takich czynników jak: lokalizacja zwarcia, ułożenie kabli WN w wykopie, konfiguracja żył powrotnych oraz rezystancja uziemienia żył powrotnych. Uzyskane wyniki pozwalają na weryfikację kryteriów wykrywania zwarć doziemnych sieci WN.

2

On rapid multidisciplinary response aspects for Samos 2020 M7.0 earthquake

Foumelis Michael, Papazachos Costas, Papadimitriou Eleftheria, Karakostas Vasileios, Ampatzidis Dimitrios, Moschopoulos Giorgos, Kostoglou Anastasios, Ilieva Maya, Minos-Minopoulos Despina, Mouratidis Antonios, Kkallas Charalambos, Chatzipetros Alexandros

Acta Geophysica

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2021

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Vol. 69, no. 3

1025--1048

EN

Following the M7.0 earthquake that struck the Greek island of Samos and Turkey’s western coast, causing extensive damage and casualties, we combined existing knowledge geodatabases concerning historical seismicity and rupture zones with seismological and geodetic measurements as well as with modelling and in situ observations, to provide an assessment of rapid response to the seismic event. In this paper, we demonstrate that in the frame of the gradual provision of information from the individual scientifc disciplines, taking into account their respective potential and limitations, a multidisciplinary approach is able to address more efciently rapid response issues in order to allow efective preliminary interpretation of the earthquake activity, even within the frst 24 h of the event. It focuses on the assessment of the timely provision of information by each discipline, evaluating the access to primary data sources as well as the maturity of the techniques in terms of accuracy and rapid data processing. Within a period of less than a week, several constraints were partially compensated for, allowing the delivery of more robust results and interpretation. The study highlights the readiness level of the various domains that has been signifcantly improved over the past years, including rapid seismological solutions, systematic availability of free and open Earth Observation data and on-demand online processing through dedicated platforms. Their combination with routinely applied inversion modelling and timely in situ observation is leading to improved operational response levels.

3

Integrated 3D geological modeling of Sonda-Jherruck coal field, Pakistan

Jiskani I. M., Siddiqui F. I., Pathan A. G.

Journal of Sustainable Mining

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2018

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Vol. 17, iss. 3

111--119

EN

Despite being one of the largest coal fields in Pakistan, the Sonda-Jherruck coal resource is yet to be exploited. Exploration studies were done between 1981 and 1989 by the Geological Survey of Pakistan (GSP) and the United States Geological Survey (USGS). While much exploratory data is available, computer-aided geological modeling has not been carried out. The resource estimation was carried out using the traditional circular 891 method. The specified distance between observational points remains constant, disregarding continuity in seam thickness that leads to higher uncertainty. Fault modeling and geologic mapping were not performed in preliminary reports. Fault lines based on aerial maps are indicated. This study generated 3D solid seam models and a fault model of the deposit. Coal seams were modeled to produce spatial distribution maps for seam thickness. The overall in-place coal resources of the deposit are estimated to be 4.66 billion tons, however mineable resources are estimated to be 1.59 billion tons. The method of fault detection is based on drill hole data. Dipping was calculated using regular grid data and the unknown points were estimated using the inverse distance weighting squared method. The assessed fault zones were compared with the USGS fault lines and an apparent similarity was observed.

4

Six-phase symmetrical induction machine under fault states-modelling, simulation and experimental results

Rolak M., Malinowski M.

Przegląd Elektrotechniczny

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2014

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R. 90, nr 11

91--95

PL

Artykuł przedstawia podstawowy stan wiedzy z zakresu maszyn wielofazowych oraz sposób modelowania 6-fazowej, symetrycznej maszyny indukcyjnej w wybranych stanach awaryjnych podczas pracy z 2-poziomowym falownikiem napięcia. Całość układu zamodelowano i przeanalizowano w środowisku Matlab/Simulink, a następnie zweryfikowano na stanowisku eksperymentalnym.

EN

Paper presents principles of multiphase machines and modelling of symmetrical 6-phase induction machine connected to 2-level 6-phase Voltage Source Inverter during chosen fault states. Presented model was built, analyzed in Matlab/Simulink simulation software and verified on laboratory test bench.

5

Fault modeling and analysis of short defects in CMOS based reversible circuits

Amaricai A., Boncalo O.

International Journal of Microelectronics and Computer Science

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2010

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Vol. 1, nr 2

175-179

EN

This paper presents a SPICE based analysis of reversible circuits affected by the short defects: the gate oxide defect and the source-drain defect. The simulations are performed using realistic transistor models (the BSIM4 model) and take into account the resistive nature of the gate oxide and the source drain shorts. We aim at determining dependence between the short's resistance and the output voltage. Furthermore, we analyze the timing characteristics of reversible circuits affected by such faults. The goal is to develop logic and delay fault models for CMOS based reversible gates. This way, Boolean test strategies and logic level fault tolerant mechanisms and strategies can be devised for reversible circuits.

6

An ANFIS-based data-driven method for fault accommodation

Khosravi A., Lu J.

Systems Science

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2006

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Vol. 32, no 4

45-54

EN

Since occurrence of faults in different parts of a system as a complex abnormality is inevitable and could cause a total failure, Fault Detection and Accommodation (FDA) is finding ever widening attention for both industrial practitioners as well as academic researchers. In the large majority of real implementation of FDA, analytical model of the system, if known, may exert an impact on the performance of an FDA method. However, in some cases, such analytical model cannot be obtained in advance. Under unavailability assumption of the analytical model, in this paper we develop a data-driven method to identify and model three kinds of faults in nonlinear systems. Two Adaptive Neural-Fuzzy Inference Systems (ANFISs) are employed in this method, i.e. the first one is used for building a model of the faultless plant using the historical data, and the second one for modeling the occurred faults. Parameters of the second ANFIS are adjusted in an indirect way based on minimization of difference between actual and model outputs. Simulation results for a nonlinear system are also presented to demonstrate the potentiality of the proposed method for fault identification.

7

Fault injection stress strategies in dependability analysis

Sosnowski J., Gawkowski P., Lesiak A.

Control and Cybernetics

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2004

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Vol. 33, no 4

679-699

EN

The paper deals with the problem of testing computer system's susceptibility to hardware faults by means of software implemented fault injectors. Basing on our experience with fault injection techniques we present various strategies of fault stressing in relevance to fault impact analysis in the function of the application input data profile, fault injection profile in time and space, resource activities etc. We discuss the problem of test result qualification and significance. Fault hardening at the software level is also outlined. The considerations presented are illustrated with numerous experimental results obtained in Windows and Linux environments.