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Ocean Thermal Energy Conversion
Aashay Tinaikar,
Ajinkya Padate,
Jainish Jain
Issue:
Volume 2, Issue 4, August 2013
Pages:
143-146
Published:
10 August 2013
Abstract: A closed cycle ocean thermal energy conversion basically involves a working fluid which has a boiling point just low below ambient temperature. This fluid is then evaporated using warm sea water and then used to run turbines. This evaporated gas is then condensed using cold seawater. In this paper a study is being made to install a super heater between the evaporator and the turbine. The various consequences due to this technical advancement have been discussed taking into consideration all the components in the OTEC plant. As the energy requirement to run pumps cannot be avoided, to increase the overall efficiency of the plant an effort is being made to increase the net energy output of the turbine. This can be achieved by heating the working fluid above its saturation temperature thus increasing its enthalpy indirectly increasing the net output of the turbine. Along with a super heater a pre-heater has been installed which helps to compensate the heat losses in heat exchangers. Both the super heater and pre-heater have been developed using non-conventional energy resources and no external energy input is required. Along with this an economic study has also been made which supports the proposed idea.
Abstract: A closed cycle ocean thermal energy conversion basically involves a working fluid which has a boiling point just low below ambient temperature. This fluid is then evaporated using warm sea water and then used to run turbines. This evaporated gas is then condensed using cold seawater. In this paper a study is being made to install a super heater bet...
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Controlling of UPFC Parameters Using Fuzzy Logic Based Supplementary Damping Controller
Bairu Vijaykumar,
Nandiraju Venkata Srikanth
Issue:
Volume 2, Issue 4, August 2013
Pages:
147-153
Received:
10 July 2013
Published:
10 August 2013
Abstract: In this paper, use of the additional supplementary damping controller for unified power flow controller (UPFC) to damp out low frequency oscillations in a heavily loaded power system is investigated. Normal damping controllers are inferior when the power system is subjected to large and fast changing loads. In order to handle the situation, an additional supplementary damping controller for UPFC is designed using Fuzzy logic technique. The effectiveness of the proposed controller on damping low frequency oscillations is tested and demonstrated through simulation studies for single machine connected to infinite bus power system (SMIB). In addition power system response with UPFC damping controller & Fuzzy logic based supplementary damping controller (FLSDC) are compared at various loading conditions. It can be concluded that Fuzzy logic based supplementary damping controller improves greatly the system stability under heavily loaded conditions.
Abstract: In this paper, use of the additional supplementary damping controller for unified power flow controller (UPFC) to damp out low frequency oscillations in a heavily loaded power system is investigated. Normal damping controllers are inferior when the power system is subjected to large and fast changing loads. In order to handle the situation, an addi...
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Effectiveness of FACTS Controllers and HVDC Transmissions for Improving Power System Stability and Increasing Power Transmission Capability
Molla Shahadat Hossain Lipu,
Tahia Fahrin Karim
Issue:
Volume 2, Issue 4, August 2013
Pages:
154-163
Received:
27 June 2013
Published:
20 August 2013
Abstract: With an increasing demand on energy and the construction of large generation units especially opening of electric power markets, it becomes more and more important to provide stable, secure, controlled and high quality electric power on today’s environment. The regulatory constraints on the expansion of the transmission network has resulted in reduction of stability margins and increased the risks of cascading outages and blackouts. Among many possible solutions to overcome these challenges, FACTS devices and HVDC systems play an important role. These type of devices/systems have shown to be capable in stabilizing transmission systems, resulting in higher transfer capability. FACTS devices and HVDC transmissions have emerged as important solutions to help power systems to increase stability margins. Some of these power electronics-based components have the main function of controlling reactive power (SVC and STATCOM) and some others to control active power (as TCSC and CSC-HVDC transmission). All these devices are also capable of damping electromechanical oscillations. This paper presents a comprehensive review of operation of different types of FACTS controllers in the power system for stability enhancement in term of shunt compensators, series compensators as well as combinations of these two types of compensators. The paper also demonstrates different types of HVDC technology as well as its effectiveness to improve the voltage profile of power system.
Abstract: With an increasing demand on energy and the construction of large generation units especially opening of electric power markets, it becomes more and more important to provide stable, secure, controlled and high quality electric power on today’s environment. The regulatory constraints on the expansion of the transmission network has resulted in redu...
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Physical Processes in the Damping of Electromechanical Oscillations of the Synchronous Machine with Magnitude-Phase Excitation Controller
Issue:
Volume 2, Issue 4, August 2013
Pages:
164-171
Received:
8 August 2013
Published:
30 August 2013
Abstract: Physical processes the damping of the synchronous machine electromechanical oscillations without excitation control, with proportional automatic voltage regulator (AVR-P), and magnitude-phase excitation controller (MPH-EC), which is responsive to the deviations of the magnitude and phase of the terminal voltage phasor are considered. The advantages of the MPH-EC, compared with the above other structures excitation control are discussed. A calculation example of the small signal stability gain margin at active power of the synchronous machine with the above structures of the excitation controllers for the simplest model "single machine - infinite bus" is examined. From this example follows, that the variable small signal stability gain margin of the MPH-EC exceeds that parameter for AVR-P, and excitation control with power system stabilizer (AVR+PSS) with a some adjustable rotor angle deviation.
Abstract: Physical processes the damping of the synchronous machine electromechanical oscillations without excitation control, with proportional automatic voltage regulator (AVR-P), and magnitude-phase excitation controller (MPH-EC), which is responsive to the deviations of the magnitude and phase of the terminal voltage phasor are considered. The advantages...
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Online Adaptive Neurofuzzy Based SVC Control Strategy for Damping Low Frequency Oscillations in Multi-Machine Power System
Saima Ali,
Shahid Qamar,
Laiq Khan,
Umer Akram
Issue:
Volume 2, Issue 4, August 2013
Pages:
172-183
Received:
21 July 2013
Published:
30 August 2013
Abstract: An online auxiliary control was designed for Static Var Compensator (SVC) to improve the poorly damped oscillations in multi-machine power system subjected to small and large disturbances. This paper presents auxiliary control based on Adaptive NeuroFuzzy (ANF) control using triangular membership function. Such a model free based control does not require any prior information about the system and is robust to system changes quickly. To minimize the cost function and to tune the parameters of the antecedent and consequent part of the proposed control, a Gradient Descent (GD) learning algorithm is used. The time domain simulation results were carried out for two machine test system for four different cases. In order to exploit the performance and robustness of ANF control, the results were compared with conventional PI and no control. Simulation results and performance indices reveal that the proposed control outperforms during various fault conditions and hence improves the transient stability to a great extend.
Abstract: An online auxiliary control was designed for Static Var Compensator (SVC) to improve the poorly damped oscillations in multi-machine power system subjected to small and large disturbances. This paper presents auxiliary control based on Adaptive NeuroFuzzy (ANF) control using triangular membership function. Such a model free based control does not r...
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