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ACPTDF for Multi-transactions and ATC Determination in Deregulated Markets Ashwani Kumar Sharma; Jitendra Kumar
International Journal of Electrical and Computer Engineering (IJECE) Vol 1, No 1: September 2011
Publisher : Institute of Advanced Engineering and Science

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Abstract—Available transfer capability in the transmission network has become essential quantity to be declared well in advance for its commercial use in a competitive electricity market. Its fast computation using DC load flow based approach is used worldwide for on line implementation. Many authors have proposed the ATC calculation based on DC/AC load flow approach. In this paper, AC PTDF based approach has been proposed for multi-transaction cases using power transfer sensitivity and Jacobian calculated with three different methods. The methods can be implemented for any number of transactions occurring simultaneously. The results have been determined for intact and line contingency cases taking multi-transaction/simultaneous as well as single transaction cases. The main contributions of the paper are: (i) ATC determination for multi-transactions environment, (ii) ATC determination and comparison with three approaches of PTDF calculations, (iii) LODFs with line contingency cases for multi-transaction environment and thereby ATC determination. The results have also been obtained with DC method for comparison. The proposed method have been applied for IEEE 24 bus RTS. Keywords: Available transfer capability, AC load flow, AC power transfer distribution factors , line outage contingency, line outage distribution factors, multi-transactions, simultaneous transactions.DOI:http://dx.doi.org/10.11591/ijece.v1i1.61
DFT-based Study of Electric Field Effect on the Polarizability of Three Ringed Nematic Liquid Crystal Molecules Upadhyay, Pranav; Mishra, Mirtunjai; Trivedi, Ankur; Kumar, Jitendra; Kumar, Asheesh; Kumar, Devesh
Makara Journal of Science Vol. 24, No. 4
Publisher : UI Scholars Hub

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Owing to its successful application to complex molecular systems, computational density functional theory (DFT) has been used to study the effect of an electric field on the molecular polarizability and HOMO–LUMO gap of 1-phenyl-4-{2-[(1s,4r)-4-pentylcyclohexyl]ethyl}benzene (1) and its fluoro-, chloro-, and cyano- derivatives, namely, 1-fluoro-4-(4-{2-[(1s,4r)-4-pentylcyclohexyl]ethyl}phenyl)benzene (2), 1-chloro-4-(4-{2-[(1s,4r)-4-pentylcyclohexyl]ethyl}phenyl)benzene (3), and 4-(4-{2-[(1s,4r)-4-pentylcyclohexyl]ethyl}phenyl)benzonitrile (4). These molecules belong to the family of nematic liquid crystals with three rings: two benzene and one cyclohexane. Furthermore, two DFT approaches, namely, B3LYP and M062X, have been used to examine the results obtained. This study reveals a remarkable feature: the polarizability of these molecules follows nearly a step function when varied with respect to the electric field. The 4-(4-{2-[(1s,4r)-4-pentylcyclohexyl]ethyl}phenyl)benzonitrile (4) polarizes more than all other derivatives, whereas 1-fluoro-4-(4-{2-[(1s,4r)-4-pentylcyclohexyl]ethyl}phenyl) benzene (2) has the widest stability region of them all. With the increase in the electric field, polarizability increases in a smooth manner until a point called here the shoot-up point at which polarizability switches to a higher value and remains nearly constant as the field increases further. However, beyond a certain value of the electric field, polarizability undergoes a steep fall. It is also found that the effective length (long molecular axis) of the molecule has a direct effect on its polarizability.