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Vishākhapatnam, India

Sridevi J.,Gokaraju Rangaraju Institute of Engineering and Technology | Amarnath J.,JNTUH College of Engineering | Govinda Rao G.,Gayatri Vidya Parishad
International Journal of Applied Engineering Research | Year: 2012

Congestion management is one of the major tasks performed by system operators to ensure the operation of transmission system within operating limits. In deregulated electricity market transmission congestion occurs when there is insufficient transmission capacity to simultaneously accommodate all constraints for transmission of a line. In this paper, transmission congestion distribution factors based on sensitivity of line real power have been proposed to identify the congestion clusters. The system operator can identify the generators from the most sensitive congestion clusters to reschedule their generation optimally to manage transmission congestion based on generator sensitivity efficiently. The role of thyristor controlled phase angle regulator and Thyristor controlled series Capacitor have been investigated for reducing the transmission congestion cost after locating it optimally in the system based on improved performance index under normal and contingency conditions. The effectiveness of the proposed method has been carried out on 124 bus Indian Utility System. © Research India Publications. Source


Sridevi J.,Gokaraju Rangaraju Institute of Engineering and Technology | Amarnath J.,Jawaharlal Nehru University | Govinda Rao G.,Gayatri Vidya Parishad
International Review on Modelling and Simulations | Year: 2011

It is becoming increasingly important for power system planning and operating engineers to be capable of performing comprehensive voltage stability analyses of the systems. This need is largely due to the recent trends towards operating systems under stressed conditions-as a result of increasing system loads without sufficient transmission and/or generation enhancements. There have been many failures, due to voltage instability in power systems around the world. This paper is mainly concerned with optimal location of Thyristor Controlled Series Capacitor and Static VAr Compensator using loss sensitivity method for voltage stability improvement even at critical line outages contingency cases. The effectiveness of the proposed method has been tested on an IEEE 118 bus system and 62 bus Indian Utility System. The results show that the suggested method of Static VAr Compensator placement is effective than Thyristor Controlled Series Capacitor for voltage stability improvement during normal as well as critical contingency cases. © 2011 Praise Worthy Prize S.r.l. - All rights reserved. Source


Srikanth V.,Andhra University | Shyamala P.,Andhra University | Satyanarayana A.,Andhra University | Subba Rao P.V.,Gayatri Vidya Parishad
Indian Journal of Chemistry - Section A Inorganic, Physical, Theoretical and Analytical Chemistry | Year: 2012

Micellisation behaviour of mixed surfactants of CTAB and Triton X-100 in the presence of isatin has been studied by surface tension measurements over a wide range of Triton X-100 mole fractions and total surfactant concentrations. The average interaction parameter has been evaluated using Rubingh theory and found to be -0.396 indicating synergistic behaviour in the mixed micelles. Kinetic studies showed that the pseudo first order rate constant increases with increase in mole fraction of Triton X-100 at constant total surfactant concentration and decreases with increase in total surfactant concentration at constant mole fraction of Triton X-100. Kinetic analysis has been carried out using a Berezin pseudophase model and binding constants determined to explain the micellar effect. Source


Padma M.,Andhra University | Shyamala P.,Andhra University | Satyanarayana A.,Andhra University | Subba Rao P.V.,Gayatri Vidya Parishad | Mathew A.,Andhra University
Indian Journal of Chemistry - Section A Inorganic, Physical, Theoretical and Analytical Chemistry | Year: 2013

The kinetics of the reduction of toluidine blue by ascorbic acid has been studied in the presence of CTAB/CHCl3/hexane/water reverse micelles. In the absence of added acid, the reaction obeys simple first order kinetics with respect to both the reactants. The second order rate constant in the presence of reverse micelles, kw (0.027 M -1 s -1) was found to be about sixty times greater than that in aqueous medium, ko (4.50×10-4 M -1 s -1) under identical experimental conditions. The significant increase is attributed to the concentration effect in the reverse micelles, and, lower micro-polarity due to the reverse micelles, which facilitates the reaction between oppositely charged ions. The effect of variation of W (= [H 2O]/[CTAB]) at constant [CTAB] and variation of [CTAB] at fixed W has been studied. The kinetics at W < 6 is explained on the basis of the special properties of the entrapped water, while the kinetics at W > 10 is explained on the basis of ionic strength. Source


Sridevi J.,Gokaraju Rangaraju Institute of Engineering and Technology | Amarnath J.,Jawaharlal Nehru University | Govinda Rao G.,Gayatri Vidya Parishad
International Review on Modelling and Simulations | Year: 2011

Available Transfer Capability (ATC) is an important index for determining power delivery contracts and managing transmission congestion. In power markets, large amount of uncertainties and dynamic, continuous and time-varying features of power systems have great impacts on ATC. Congestion management is one of the major tasks performed by system operators to ensure the operation of transmission system within operating limits. In the emerging electric power market, the congestion management becomes extremely important and it can impose a barrier to the electricity trading. This paper deals with the optimal choice and allocation of FACTS devices for congestion management and ATC enhancement using sensitivity indices. Two methods based on optimal power flow are proposed to alleviate congestion in transmission lines and tested. The first method reduces the reactive power losses under normal and contingency conditions with multi type FACTS devices which is tested on IEEE 24 rts system. The second method alleviates congestion in transmission lines with optimal placement of TCSC and is tested on 30 bus system. © 2011 Praise Worthy Prize S.r.l. - All rights reserved. Source

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