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Tripathy S.C.,Ghanashyam Hemalata Institute of Technology and Management
International Journal of Energy, Environment and Economics | Year: 2011

We have learned that it is possible to supply a given load demand in an infinite number of operating configuration. It is necessary choose one particular configuration; i.e., the systems operator must specify exactly two variables per bus and, in addition, decide on appropriate tap settings on all regulating transformers. For a type 1 bus he must specify PG and QG, for a type 2 bus, PG and {pipe} V {pipe}, and for the slack bus, he must select {pipe} V {pipe}. On what basis are these specifications made? The simplest method is to use an "intelligent guess" Many systems are today operated on that basis. In this paper we discuss more sophisticated methods for selecting a "best" or "optimum" operating strategy. It must be remembered, however, that in the final analysis someone must make the decision as to what shall be understood by best or optimum in each particular instance. The choice of an optimum criterion is therefore always a subjective one. © 2011 Nova Science Publishers, Inc. Source


Tripathy S.C.,Ghanashyam Hemalata Institute of Technology and Management
International Journal of Energy, Environment and Economics | Year: 2010

As noted earlier, the most fundamental task of energy analysis is to define alternative options - for energy pricing, for energy sector investments, and so on - and quantify their impacts on the objectives established for national energy planning. If, say, two policies are to be evaluated, there must also exist some explicit basis for comparing them, preferably on some ordinal scale of measurement. That is, we are interested not only in a ranking of alternatives, but in general one also wishes to know by exactly how much one alternative is better than another. This may well be an obvious point, yet it is particularly important where multiple objectives must be simultaneously evaluated: policy A may be better to policy B in terms of, say, some cost-minimization objective, but worse when evaluated on some environmental criterion. But if we know that B is only slightly less good in economic terms, that is an extremely important piece of additional information for the decision-maker who must ultimately make the trade-off between the two objectives. Examining solutions in the vicinity of the cost-minimizing optimum proves to be very important in such solutions, yet it is rarely done. © 2010 Nova Science Publishers, Inc. Source


Sahu L.,Ghanashyam Hemalata Institute of Technology and Management | Mishra A.K.,National Institute of Technology Rourkela | Dutta K.,National Institute of Technology Rourkela
Journal of Materials Engineering and Performance | Year: 2014

Ratcheting fatigue behavior of a non-conventional stainless steel X12CrMnNiN17-7-5 has been investigated with varying combinations of mean stress (σm) and stress amplitude (σa) at room temperature using a servo-hydraulic universal testing machine. X-ray diffraction profile analysis has been carried out for assessing possible martensitic phase transformation in the steel subjected to ratcheting deformation. The results indicate that ratcheting strain as well as volume fraction of martensite increases with increasing σm and/or σa; the phenomenon of strain accumulation is considered to be governed by the associated mechanics of cyclic loading, increased plastic damage as well as martensitic transformation. A correlation between strain produced by ratcheting deformation and martensitic transformation has been established. © 2014, ASM International. Source


Tripathy S.C.,Ghanashyam Hemalata Institute of Technology and Management
International Journal of Energy, Environment and Economics | Year: 2014

There is a continuing tendency to apply many of the powerful results of modern control theory to various industrial processes. Power systems have been indicated as one area where significant progress can be expected. Practically all results of modern control theory require that models of the processes in terms of state equations are available. The need to obtain such models has been a strong motivation for research in the area of modelling and identification. Some progress made in this area is reviewed in this paper. Modelling based on physical equations and on plant experiments is discussed and compared. Particular emphasis is given to parameter estimation techniques like the maximum likelihood method which offer a possibility of combining physical a priori knowledge with experimental investigations. The formulation of identification problems is discussed, including the choice of criteria and model structures. The techniques are illustrated by applications to data obtained from measurements on various components of a power system. The examples include an electric generator, a nuclear reactor and a drum boiler, and serve to illustrate the potentials and limitations of system identification and modelling techniques when they are applied to real data. © Nova Science Publishers, Inc. Source


Tripathy S.C.,Ghanashyam Hemalata Institute of Technology and Management
International Journal of Energy, Environment and Economics | Year: 2013

Most dc transmission lines use a return path through the ground or seawater or both, either continuously or for short times of emergency. For brevity, such return paths are called ground returns even if the sea constitutes all or part of the path. The ground path has a very low resistance and correspondingly low power loss in comparison with a metallic line conductor of economical size and equal length if the ground electrodes are properly designed. The resistance is low because direct current in the earth in a steady state, unlike transient or alternating current, does not follow closely the route of the metallic conductor but spreads over a very large cross-sectional area in both depth and width. The resistance of this path is essentially independent of the length of the line and may be regarded merely as the sum of the resistances associated with each electrode unless the electrodes are near one another-which certainly would not be true in longdistance transmission. These resistances can be made low. © © Nova Science Publishers, Inc. Source

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