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Bhatt P.,Charotar Institute of Technology | Ghoshal S.P.,National Institute of Technology Durgapur | Roy R.,Sardar Vallabhbhai National Institute of Technology, Surat
Renewable Energy | Year: 2012

Among the several wind generation technologies, variable-speed wind turbines utilizing doubly fed induction generators (DFIG) are gaining momentum in the power industry. Increased penetration of these wind turbine generators displaces conventional synchronous generators which results in erosion of system frequency. With this assertion, the paper analyzes the dynamic participation of DFIG for frequency control of an interconnected two-area power system in restructured competitive electricity market. Frequency control support function responding proportionally to frequency deviation is proposed to take out the kinetic energy of wind turbine for improving the frequency response of the system. Impacts of varying wind penetration in the system and varying active power support from DFIG on frequency control have been investigated. The presence of thyristor controlled phase shifter (TCPS) in series with the tie-line and Superconducting Magnetic Energy Storage (SMES) at the terminal of one area in conjunction with dynamic active power support from DFIG results in optimal transient performance for PoolCo transactions. Integral gains of AGC loop and parameters of TCPS and SMES are optimized through craziness-based particle swarm optimization (CRPSO) in order to have optimal transient responses of area frequencies, tie-line power deviation and DFIG parameters. © 2011 Elsevier Ltd. Source


Bhatt P.,Charotar Institute of Technology | Roy R.,Sardar Vallabhbhai National Institute of Technology, Surat | Ghoshal S.P.,National Institute of Technology Durgapur
2010 IEEE 11th International Conference on Probabilistic Methods Applied to Power Systems, PMAPS 2010 | Year: 2010

This paper examines the impact of increased penetration of doubly fed induction generator (DFIG) based wind power generation on frequency control of an interconnected two-area hydrothermal power system. The power electronic control of DFIG effectively isolates the inertia from the grid which will impose the serious threat to frequency regulation capability of the system. To mitigate the frequency stability problem, a frequency control support function is proposed which responds upon detection of network frequency excursion. A dynamic active power support by utilizing the rotational energy of the turbine blades has been obtained to arrest the initial frequency fall. Further, the effects of different wind penetration level and varying active power support from DFIG are analyzed on a market available multi-megawatt wind turbine generator. ©2010 IEEE. Source


Shah N.D.,Charotar Institute of Technology | Desai J.A.,Sardar Vallabhbhai National Institute of Technology, Surat
International Journal of Earth Sciences and Engineering | Year: 2010

As the span of the cable-stayed bridge increases, the nonlinearities also go on increasing. These nonlinearities are due to sag in the cable, axial force-bending moment interaction in the girder and tower and due to large deformations of the overall structure. Further, the nonlinearity magnifies with the influence of wind loading. Again with the increase in bridge span, the diameter of the cable, the nonlinear wind structure interaction and the wind speed spatial non-uniformity increases, which may have significant influence on the aerostatic behavior of long span cable-stayed bridges. The paper presents finite element approach for the geometric nonlinear aerostatic analysis of self anchored cablestayed bridges with different pylon configurations along with vehicular interaction. The example bridges are supported by three different pylon configurations such as H shape, A shape and Inverted Y shape. For above mentioned bridges, linear and non-linear analysis was carried out for a wind speed of 55 m/s for both self anchored and partially earth anchored (bi-stayed) bridges. The results showed that these factors have significant influence on the aerostatic behavior and should be considered in the aerostatic analysis of long span cable stayed bridges. Analysis results will be useful for the designers to consider the shape of pylon at the initial stage of design. Again the results indicate the significant influence of pylon shapes on aerostatic behavior of such long span bridges © 2010 CAFET-INNOVA TECHNICAL SOCIETY. All rights reserved. Source


Bhatt P.,Charotar Institute of Technology | Roy R.,Sardar Vallabhbhai National Institute of Technology, Surat | Ghoshal S.P.,National Institute of Technology Durgapur
International Journal of Electrical Power and Energy Systems | Year: 2010

This paper presents the comparative performance analysis of the two specific varieties of controller devices for optimal transient performance of automatic generation control (AGC) of an interconnected two-area power system, having multiple thermal-hydro-diesels mixed generating units. The significant improvement of optimal transient performance is observed with the addition of a thyristor-controlled phase shifter (TCPS) in the tie-line or capacitive energy storage (CES) units fitted in both the areas. Three different optimization algorithms are adopted for the sake of comparison of optimal performances and obtaining the optimal values of the gain settings of the devices independently. Craziness based particle swarm optimization (CRPSO) proves to be moderately fast algorithm and yields true optimal gains and minimum overshoot, minimum undershoot and minimum settling time of the transient response for any system. Comparative studies of TCPS and CES by any algorithm reveals that the CES units fitted in both the areas improve the transient performance to a greater extent following small load disturbance(s) in both the areas. © 2009 Elsevier Ltd. All rights reserved. Source


Bhatt P.,Charotar Institute of Technology | Ghoshal S.P.,National Institute of Technology Durgapur | Roy R.,Sardar Vallabhbhai National Institute of Technology, Surat
International Journal of Electrical Power and Energy Systems | Year: 2010

In this paper, automatic generation control with interconnected two-area multi-unit all-hydro power system and two more test systems as all-thermal and thermal-hydro mixed haves been investigated. The transfer function of hydro turbine having non-minimum phase characteristics makes it different from the steam turbine. Upon application of small load perturbation to such all-hydro system, the frequency is severely disturbed and the system eventually becomes unstable. To stabilize the system for such load disturbance, comparative transient performance of two cases as (a) Thyristor Controlled Phase Shifter (TCPS) installed in series with the tie-line in coordination with Superconducting Magnetic Energy Storage (SMES) and (b) SMES located at each terminal of both areas are analyzed. It is observed that the case (b) i.e. SMES located at each terminal of both areas suppresses the frequency oscillations more effectively in integral controller assisted AGC of two-area multi-unit all-hydro system and the other two systems as well. In addition, the effectiveness of proposed frequency stabilizers is guaranteed by analyzing the transient responses of the system with different system parameters, various load patterns and in the event of temporary and permanent tie-line outage. Gains of the integral controller in AGC loop and parameters of TCPS and SMES are optimized with the help of a relatively novel particle swarm optimization, developed by the authors, called as craziness-based particle swarm optimization (CRPSO). The optimizing performance has been compared to that of real-coded genetic algorithm (RGA) to establish its superiority. © 2010 Elsevier Ltd. All rights reserved. Source

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