فهرست مطالب

  • Volume:1 Issue: 1, 2012
  • تاریخ انتشار: 1391/07/26
  • تعداد عناوین: 7
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  • Hossein Nasiraghdam*, Morteza Nasiraghdam Page 1
    The operation of a distribution system in the presence of distributed generation systems has some advantages and challenges. Optimal sizing and siting of DG systems has economic, technical, and environmental benefits in distribution systems. Improper selection of DG systems can reduce these advantages or even result in deterioration in the normal operation of the distribution system. DG allocation and capacity determination is a nonlinear optimization problem. The objective function of this problem is the minimization of the total loss of the distribution system. In this paper, the Improved Harmony Search (IHS) algorithm has been applied to the optimization problem. This algorithm has a suitable performance for this type of optimization problem. Active and reactive power demands of the distribution system loads are dependent on bus voltage. This paper verifies the effect of voltage dependent loads on system power characteristics. The load model has an inevitable impact on DG sizing and placement. The proposed algorithm implemented and tested on 69-bus distribution systems and the impact of voltage dependent load models are demonstrated. The obtained results show that the proposed algorithm has an acceptable performance.
    Keywords: Distributed generation, improved harmony search, DG sizing, sitting, load model
  • Meisam Mahdavi *, Ali Nazari, Vahid Hosseinnezhad, Amin Safari Page 18
    In this paper Power system stability enhancement through static synchronous compensator (STATCOM) based controller is investigated. The potential of the STATCOM supplementary controllers to enhance the dynamic stability is evaluated. The design problem of STATCOM based damping controller is formulated as an optimization problem according to the eigenvalue based objective function that is solved by a particle swarm optimization (PSO) algorithm. The controllers are tuned to simultaneously shift the lightly damped and un-damped electro-mechanical modes of machine to a prescribed zone in the s plane. The results analysis reveals that the designed PSO based STATCOM damping controller has an excellent capability in damping the power system low frequency oscillations and enhance greatly the dynamic stability of the power system.
    Keywords: STATCOM, Particle swarm optimization, damping controller, Dynamic stability
  • Mozhgan Balavar* Page 26
    FACTS technology has considerable applications in power systems, such as; improving the steady state performance, damping the power system oscillations, controlling the power flow, and etc. STATCOM is one of the most important FACTS devices used in the parallel compensation, enhancing transient stability and etc. Since three phase fault is widespread in power systems, in this paper STATCOM is used to improve the transient stability of power system when three phase fault occurred. Neural Network has been used for adjusting the gain of the supplementary controller of STATCOM. The simulation performed in MATLAB / Simulink software. Simulation results showed when STATCOM combines with proposed Neural Network based supplementary controller; the transient stability of power system improves.
    Keywords: FACTS, STATCOM, Artificial Neural Network (ANN), Power Oscillation Damping
  • Saeid Jalilzade*, Mehdi Mardani Page 32
    Measurement of magnitude and frequency of the voltage flicker is very important for monitoring and controlling voltage flicker efficiently to improve the network power quality. This paper presents two new methods for measurement of flicker signal parameters using Shuffled Frog Leaping Algorithm (SFLA) and Imperialist Competitive Algorithm (ICA). This paper estimates fundamental voltage and flicker magnitudes and frequencies with proposed methods. The goal is to minimize the error of the estimated magnitudes and frequencies via a designed fitness function. At first, we introduce voltage flicker and its measuring techniques. Then voltage flicker model is analyzed. At the next part, a review of SFLA and ICA is presented. These methods will be applied to a test voltage signal and the results are be analyzed.
    Keywords: Voltage flicker signal, Flicker magnitude, frequency measurement, Shuffled Frog Leaping Algorithm (SFLA), Imperialist Competitive Algorithm (ICA)
  • M. Asghari *, M. A. Badamchizadeh, M. E. Akbari Page 40
    With increasing use of robots instead of human in industrial, medicine and military applications etc. the importance of research on designing and building of robots is increasing. In this paper various methods of the human hand motion simulation has been investigated and we used one of most common method named Data-gloves which extract data from hand and then we simulated hand motion during several processing stages. At first step we designed and built circuits to digitize analog data received from sensors and we sent them to computer. Then we received extracted data in MATLAB and processed them to simulate bending of the wrist and fingers joints graphically. In this method we mapped data linearly to 0-90 and rotate points around relative Coordinate axis in the specific conditions. Results show that we can simulate hand motion in real time with low cost, lowest error and without complex and expensive equipments.
    Keywords: Hand motion simulation, Data, Glove, Data extraction circuit, simulation in MATLAB
  • Ali Ahmadian*, Masoud Aliakbar Golkar Page 48
    The aim of this paper is to investigate a novel approach for output feedback damping controller design of STATCOM in order to enhance the damping of power system low frequency oscillations (LFO). The design of output feedback controller is considered as an optimization problem according with the time domain-based objective function which is solved by a honey bee mating optimization algorithm (HBMO) that has a strong ability to find the most optimistic results. The effectiveness of the proposed controller are tested and demonstrated through nonlinear time-domain simulation studies over a wide range of loading conditions. The simulation study shows that the designed controller by HBMO has a strong ability to damping of power system low frequency oscillations. Moreover, the system performance analysis under different operating conditions show that the φ based controller is superior to the C based controller.
    Keywords: FACTS, STATCOM, Honey Bee Mating Optimization, Damping Controller, Low Frequency Oscillations, Power System, Dynamic Stability
  • Ali Nazari, Amin Safari*, Hossein Shayeghi Page 56
    This paper presents a biogeography-based optimization (BBO) algorithm to solve the economic load Dispatch (ELD) problem with generator constraints in thermal plants. The applied method can solve the ELD problem with constraints like transmission losses, ramp rate limits, and prohibited operating zones. Biogeography is the science of the geographical distribution of biological species. The models of biogeography explain how a organisms arises, immigrate from an environment to another and getseliminated. The BBO has some characteristics that are shared with other population based optimization procedures, similar to genetic algorithms (GAs) and particle swarm optimization (PSO).The BBO algorithm mainly based on two steps: migration and mutation. The BBO has some good features in reaching to the global minimum in comparison to other evolutionary algorithms. This algorithm applied on two practical test systems that have six and fifteen thermal units, results of this paper are used to see the comparison between performances of the BBO algorithm with other existing algorithms. The result of this investigation proves the efficiency and good performance of applying BBO algorithm on ELD problem and show that this method can be a good substitute for other algorithms.
    Keywords: biogeography, based optimization, economic load dispatch, prohibited operating zone, ramp rate limits