The Experts below are selected from a list of 57966 Experts worldwide ranked by ideXlab platform
Vladimir Terzija - One of the best experts on this subject based on the ideXlab platform.
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Intelligent two-port Numerical Algorithm for transmission lines disturbance records analysis
Electrical Engineering, 2008Co-Authors: Z. Radojević, Vladimir TerzijaAbstract:This paper presents a new intelligent Numerical Algorithm for analysis of transmission lines disturbance records. The Algorithm improves the existing methodologies for fault location, adaptive autoreclosure, detailed disturbance records analysis, and fault data management. It is based on the processing of voltages and currents recorded at both of the line terminals. The Algorithm does not require synchronized sampling of data from the line terminals. The proposed Algorithm is derived in the spectral domain and is based on the application of the discrete Fourier transform. In the Algorithm development, the fault arc is included in the complete fault model. One of advanced Algorithm features is ability to determine both the arc and the fault/tower-footing resistance. The Algorithm is thoroughly tested using EMTP simulation and real data records.
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Effective Two-terminal Numerical Algorithm for Overhead Lines Protection
Electrical Engineering, 2007Co-Authors: Z. Radojević, Vladimir TerzijaAbstract:In the paper an effective Numerical Algorithm for overhead lines protection, particularly fault location and adaptive autoreclosure, is presented. It is based on the two terminal line currents and voltages acquisition. For this purposes the synchronized sampling of all analogue input variables, i.e. the application of the Global Position System/Phasor Measurement Units, was assumed. The Algorithm presented is derived in the spectral domain. By this the set of third harmonics variables and line parameters was also used. The prerequisite for successfully adaptive autoreclosure functionality realization was the suitable modelling of the electrical arc. Arc was considered as a source of higher harmonics, distorting by this other electrical variables. In the arc modelling, results of laboratory testing were used. Algorithm is tested for a typical network configuration, assuming by this that the line considered was short enough to neglect its capacitive nature. Based on the results obtained, it is very realistic that the Algorithm presented could be implemented in praxis in modern Intelligent Electronic Devices (IEDs).
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Numerical Algorithm for overhead lines protection and disturbance records analysis
IET Generation Transmission & Distribution, 2007Co-Authors: Z. Radojević, Vladimir TerzijaAbstract:A new and very efficient Numerical Algorithm for overhead lines protection is presented. The Algorithm particularly improves up-to-date solutions with regard to fault location, adaptive autoreclosure, detailed disturbance records analysis and fault data management. It is based on the two-terminal line currents and voltages acquisition. For this purpose, the synchronised sampling of all analogue input variables, that is, the application of the global positioning system/phasor measurement units, was assumed. The Algorithm presented is derived in the spectral domain and based on the application of the discrete Fourier transform. The prerequisite for the successful adaptive autoreclosure functionality realisation was the suitable modelling of the electrical arc. The electrical arc was considered as a source of higher harmonics. These are included in the complete fault model, which was the starting point for the development of this new Algorithm. One of the Algorithm's sophisticated features is its ability to determine both the arc and the fault resistance. For the purpose of arc modelling, the results of high current laboratory testing are used. The Algorithm is tested through computer-based simulation of a line connected to two active networks. On the basis of the results obtained, it is very realistic that the Algorithm presented could be implemented in praxis in modern intelligent electronic devices. © The Institution of Engineering and Technology 2007.
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Numerical Algorithm for adaptive autoreclosure and protection of medium voltage overhead lines
IEEE Transactions on Power Delivery, 2004Co-Authors: Vladimir Terzija, Z M RadojevicAbstract:In this paper, a new Numerical Algorithm for medium-voltage overhead lines, autoreclosure, is described. The subfunction of the autoreclosure scheme that would inhibit the first shot after detecting a solid fault (as compared with an arc fault) is evaluated and presented. It is based on one terminal data processing and it is derived in the time domain. In the Algorithm the fault nature (arcing or arcless fault) is estimated using linear least error squares estimation technique. The arc, occurring on the fault point during arcing faults on overhead lines, is included in the problem consideration. In addition, by introducing the prefault load current in the existing model, better Algorithm performances and a more reliable adaptive Algorithm for autoreclosure are achieved. The Algorithm is derived for the case of three-phase symmetrical fault. The results of the Algorithm testing through computer simulation are presented. Particularly the Algorithm sensitivity to arc elongation effects, supplying network parameters, and processing of the signals in the presence of harmonics are tested and analyzed.
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adaptive underfrequency load shedding integrated with a frequency estimation Numerical Algorithm
IEE Proceedings - Generation Transmission and Distribution, 2002Co-Authors: Vladimir Terzija, H J KoglinAbstract:An approach to adaptive underfrequency load shedding, a procedure for protecting electric power systems from dynamic instability and frequency collapse, is presented. It consists of two main stages. In the first stage, the frequency and the rate of frequency change are estimated by the nonrecursive Newton type Algorithm. By using the simplest expression of the generator swing equation, in the second stage the magnitude of the disturbance is obtained. The UFLS plan is adapted to the magnitude estimated, to obtain a more efficient system for operation during emergency conditions. Results of procedure testing are demonstrated through computer simulations by using a 10-machine New England test system.
Manoj P Tripathi - One of the best experts on this subject based on the ideXlab platform.
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a new Numerical Algorithm to solve fractional differential equations based on operational matrix of generalized hat functions
Communications in Nonlinear Science and Numerical Simulation, 2013Co-Authors: Manoj P Tripathi, Vipul K Baranwal, Ram K Pandey, Om P SinghAbstract:Abstract In this paper, we propose a new Numerical Algorithm for solving linear and non linear fractional differential equations based on our newly constructed integer order and fractional order generalized hat functions operational matrices of integration. The linear and nonlinear fractional order differential equations are transformed into a system of algebraic equations by these matrices and these algebraic equations are solved through known computational methods. Further some Numerical examples are given to illustrate and establish the accuracy and reliability of the proposed Algorithm. The results obtained, using the scheme presented here, are in full agreement with the analytical solutions and Numerical results presented elsewhere.
Om P Singh - One of the best experts on this subject based on the ideXlab platform.
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a new Numerical Algorithm to solve fractional differential equations based on operational matrix of generalized hat functions
Communications in Nonlinear Science and Numerical Simulation, 2013Co-Authors: Manoj P Tripathi, Vipul K Baranwal, Ram K Pandey, Om P SinghAbstract:Abstract In this paper, we propose a new Numerical Algorithm for solving linear and non linear fractional differential equations based on our newly constructed integer order and fractional order generalized hat functions operational matrices of integration. The linear and nonlinear fractional order differential equations are transformed into a system of algebraic equations by these matrices and these algebraic equations are solved through known computational methods. Further some Numerical examples are given to illustrate and establish the accuracy and reliability of the proposed Algorithm. The results obtained, using the scheme presented here, are in full agreement with the analytical solutions and Numerical results presented elsewhere.
Jochen Voss - One of the best experts on this subject based on the ideXlab platform.
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a fast Numerical Algorithm for the estimation of diffusion model parameters
Journal of Mathematical Psychology, 2008Co-Authors: Andreas Voss, Jochen VossAbstract:Abstract In this paper, we describe a new Algorithmic approach for parameter estimation in Ratcliff's [(1978). A theory of memory retrieval. Psychological Review , 85 (2), 59–108] diffusion model. This problem, especially if inter-trial variabilities of parameters are included in the model, is computationally very expensive; the parameter estimation procedure often takes a long time even with today's high-speed computers. The Algorithm described here makes the calculation of the cumulative distribution functions for predicted process durations computationally much less expensive. This improvement is achieved by solving the Kolmogorov backward equation Numerically instead of employing the previously used closed form solution. Additionally, the Algorithm can determine the optimum fit for one of the model parameters (the starting point z ) directly, thereby reducing the dimension of the parameter search space by one. The resulting method is shown to be notably faster than the standard (closed-form solution) method for parameter estimation.
Maziar Changizian - One of the best experts on this subject based on the ideXlab platform.
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A fast non-iterative Numerical Algorithm to predict unsteady partial cavitation on hydrofoils
Applied Mathematical Modelling, 2013Co-Authors: M. Behbahani-nejad, Maziar ChangizianAbstract:A new Algorithm to predict partial sheet cavity behavior on hydrofoils is proposed. The proposed Algorithm models the unsteady partial cavitation using Boundary Element Method (BEM). In the proposed method the spatial iterative scheme is removed by means of a new approach determining the instantaneous cavity length. This iterative scheme is required in conventional Algorithms to obtain the cavity length at each time step. Performance of the new Algorithm for various unsteady cavitating flows with different reduced frequencies, cavitation numbers, hydrofoil geometries and inflow conditions are investigated. Comparison between the obtained results using the proposed method and those of conventional ones indicates that the present Algorithm works well with sufficient accuracy. Moreover, it is shown that the proposed method is computationally more efficient than the conventional one for unsteady sheet cavitation analysis on hydrofoils. ?? 2013 Elsevier Inc.
