Samantaray S.R.,Indian Institute of Technology Bhubaneswar |
Tripathy L.N.,IGIT |
Dash P.K.,Siksha O' Anusandhan University
International Journal of Electrical Power and Energy Systems | Year: 2012
The paper presents a differential energy based protection scheme for transmission line including Thyristor Controlled Series Compensator (TCSC) using time-frequency transform such as S-transform. Initially the current at sending and receiving ends are retrieved and processed through the time-frequency transform such as S-transform to generate the time-frequency patterns (frequency contours). Spectral energy content of the frequency contours of both current signals are calculated and differential energy is computed to register the fault patterns in the transmission line. The tripping signal can be issued based on a set threshold, within two cycles from the fault inception, meeting the speed criteria of the digital relay. The results indicate that the differential energy based protection scheme can reliably detect the fault patterns in TCSC line including wide variations in operating conditions of the faulted power network. © 2012 Elsevier Ltd. All rights reserved.
Kumar A.,University of Delhi |
Maheshwari S.,Netaji Subhas Institute of Technology |
Sharma C.,IGIT |
Beri N.,University of Delhi
Materials and Manufacturing Processes | Year: 2010
Electrical discharge machining (EDM) is a well-established modern machining process used to manufacture geometrically complex shapes, process hard materials that are extremely difficult to machine by conventional machining processes. This noncontact machining technique is continuously emerging from a mere tool and dies making process to a microscale machining applications. In recent years, researches have emphasized on increasing machining performance coupled with deliberate surface treatments. Additive mixed electrical discharge machining (AEDM) is a novel innovation for enhancing the capabilities of electrical discharge machining process in this direction. This article presents comprehensive history, mechanism of AEDM process, and reviews research literature in this area. The last part of this article outlines trends for future AEDM research directions. Copyright © Taylor & Francis Group, LLC.
Deshpande R.,RITM |
Kumar B.,BPIT |
IET Communications | Year: 2010
Design of finite impulse response (FIR) notch filters (NFs) with highly narrow rejection bandwidth (RBW) is suggested. RBW is the distance between 3 dB points on the response. Reduction in the RBW is achieved progressively in three stages. In the first stage, an FIR NF is designed from a second order infinite impulse response (IIR) prototype filter. For a given length L of the NF, the authors choose maximum permissible value of 'r' (the pole length of IIR prototype filter) to achieve very narrow RBW of the FIR filter. In the next stage, by using an amplitude change function (ACF): H(z)(2 - H(z)), the designed filter is sharpened. Consequently, the RBW of the resulting NF is reduced to almost half of the earlier value. This reduction of bandwidth makes the resulting NF of length 2L. In the next stage, RBW can be further reduced by the repeated sharpening of the filter by the same ACF. © 2010 The Institution of Engineering and Technology.
Maheshwari S.,Netaji Subhas Institute of Technology |
International Journal of Machining and Machinability of Materials | Year: 2011
In this paper, an attempt has been made to correlate the usefulness of powder metallurgy (PM) electrodes in electrical discharge machining (EDM). This paper explains the same with the help of experimentation on AISID2 steel in kerosene with CuW (25% Cu and 75% W) PM electrode. An L18 orthogonal array was used to identify the effect of process parameters (viz. electrode material, duty cycle, flushing pressure and current) on the performance characteristics i.e., material removal rate surface roughness and surface hardness. A grey relation grade obtained from the grey relation analysis is used to solve the EDM process with multiple performance characteristics. Experimental results have shown that electric discharge machining process performance can be improved efficiently through this approach. It is found that copper tungsten PM electrode gives better multi-objective performance than conventional copper electrode. Copyright © 2011 Inderscience Enterprises Ltd.
Sahoo A.K.,KIIT University |
International Journal of Industrial Engineering Computations | Year: 2011
This paper presents the experimental study, development of mathematical model and parametric optimization for surface roughness in turning D2 steel using TiN coated carbide insert using Taguchi parameter design and response surface methodology. The experimental plan and analysis was based on the Taguchi L27 orthogonal array taking cutting speed (v), feed (f) and depth of cut (d) as important cutting parameters. The influence of the machining parameters on the surface finish has also been investigated and the optimum cutting condition for minimizing the surface roughness is evaluated. The optimal parametric combination for TiN coated cutting insert is found to be v3-f1-d3. The ANOVA result shows that feed the most significant process parameter on surface roughness followed by depth of cut. The cutting speed is found to be insignificant from the study. The RSM model shows good accuracy between predicted values and experimental values with 95% confidence intervals and adequate. It is concluded that the developed RSM model can be effectively utilized to predict the surface roughness in turning D2 steel. © 2011 Growing Science Ltd. All rights reserved.