فهرست مطالب

Majlesi Journal of Energy Management
Volume:5 Issue: 4, Dec 2016

  • تاریخ انتشار: 1395/10/30
  • تعداد عناوین: 6
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  • Mohammad Mostafa Payami, Mahmood Joorabian Page 1
    Frequency deviation and inter-area transmitted power oscillations are under local load disturbances. This is a major concern in performance and control of interconnected power systems. In this paper, in order to minimize frequency deviations and increase production control performance, a structure of automatic control for power system production using thyristor-controlled phase-shifter, superconducting magnetic energy storage, as well as governor backlash nonlinearities effect on load frequency control is presented. The aim of this paper is to compare oscillations’ damping and stability evaluation when superconducting magnetic energy storage (SMES) is used in an area and thyristor-controlled phase-shifter (TCPS) in series with transmission line and SMES in both areas considering governor backlash nonlinearities in an interconnected two-area network. Simulation results reveal that the network with SMES-SMES is better than TCPS-SMES in terms of load frequency control.
    Keywords: Two-area power system, Governor Backlash Nonlinearities, AGC, FACTS, SMES, TCPS
  • Mojtaba Sarlack, Vahid Amir Page 7
    With regard to the increasing development of the distribution systems and their importance in the electrical network, minimizing the losses and costs of these systems should be considered. In this study, using the PSO and BAT algorithms for the capacitor and DG placement and finding size, the most appropriate voltage profile is created in the buses and the current costs and losses of capacitor and DG are minimized compared to the time before capacitor and DG placement. The solution for these two methods is divided into two parts: first part, sensitivity factor of the losses is used for optimal placement of the capacitor and DG and in the second part, BAT and PSO algorithms are used for determining the seiz of the capacitor anf optimal DG and the obtained results are compared. The objective function which has three important indices (active and reactive power losses and voltage profile) is minimized using bat and pso algorithm. Power flow is done using The Newton-Raphson method and simulation is carried out on a 34 bus test system. Placement of DGs and capacitors are done simultaneously in the test system.
    Keywords: Distribution System, Capacitor, DG, Minimizing the Costs, Losses, The Newton, Raphson method, Sensitivity Factor, BAT Algorithm, PSO Algorithm
  • Hojat Golafshani, Hossein Afrakhte, Reza Naghizadeh Page 13
    In this paper, Flexible AC Transmission Systems (FACTS) devices are used as a powerful tool for controlling power flow in power system to reduce active power losses and manage transmission lines congestion which are two main factors to restrict transmitted power in the network. Optimal location and size of these devices are specified by using artificial bee colony (ABC) algorithm which is one of the most effective method for solving optimization problems by taking into consideration minimizing active power losses and transmission lines congestion as objective functions in order to relieve the line loading of the overloaded transmission lines and increase the loadability in the transmission system. The proposed method is also able to improve voltage profile in the network. The effectiveness of proposed method is tested with IEEE 30-bus system and the test results are evaluated.
    Keywords: Loss reduction, Congestion improvement, FACTS devices, Artificial bee colony
  • M. R. Agha Kashkooli, Seyed M. Madani, Arash Kiyoumarsi Page 21
    A modified direct torque control (DTC) method is proposed for grid connection of Cascaded Doubly Fed Induction Generator (CDFIG) used in wind turbine. The presented method and its dynamic model is obtained in stator reference frame of control machine. To achieve a voltage in the stator of power machine with equal amplitude and matched phase and frequency to the grid voltage, the magnitude and frequency of stator flux is controlled respectively by two PI controllers. The inner control loops utilize hysteresis controller and pre-defined look-up table to track the reference values. The proposed control method has high performance, i.e., grid connection with zero overcurrent and fast dynamic response, during the CDFIG loading. The experimental results on a 3 kW CDFIG reveals the proposed method effectiveness for grid connection of CDFIG.
    Keywords: Cascaded Doubly Fed Induction Generator (CDFIG), Brushless Doubly Fed Induction Generator (BDFIG), Direct Torque Control (DTC), Grid Connection
  • M. R. Agha Kashkooli, Seyed M. Madani Page 27
    This paper presents an improved Direct Torque Control (DTC) of the Doubly-Fed Induction Generator (DFIG) to achieve constant switching frequency and reducing both torque and flux ripples. The proposed controller calculates a voltage vector with variable magnitude and angle, in such a way that torque and flux ripples are reduced. The Space Vector Modulation is implemented to supply the reference voltage vector to rotor windings. Main advantages of DTC methods including quick dynamic response, modest implementation and simple coordinate transforms are conserved. The simulation and experimental results supports the benefits of this method compared to conventional DTC.
    Keywords: Doubly Fed Induction Generator (DFIG), Direct Torque Control (DTC), Space Vector Modulation (SVM), Hysteretic Controller
  • Hossein Lotfi Page 33
    In this paper, the price of electric energy in the electricity market is predicted using neural networks. Multi-Layer Perceptron neural network is proposed for electricity market price prediction and Back propagation algorithm is used for neural network training. Since the load changes taking one of the factors affecting the price of electrical energy, Electric load as an important factor in predicting market price is considered in this article. Two models have been used for electricity market price prediction, and results of two methodes have been compared. Data used in this paper is related to Nord Pool Spot Market in 2015, Nord Pool Spot runs the largest market for electrical energy in Europe
    Keywords: Market Price, Prediction, Artificial Neural Network (ANN)