فهرست مطالب

Science and Technology Transactions of Electrical Engineering - Volume:39 Issue:2, 2016
  • Volume:39 Issue:2, 2016
  • تاریخ انتشار: 1394/11/16
  • تعداد عناوین: 8
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  • S. Babaeinejadsarookolaee, A. Akbari Foroud Pages 115-131
    In order to improve the reliability of the power system, sufficient amount of new capacity should be installed in the network. Usually generation units’ payoff in an energy market is not adequate to cover their expenses. Therefore, energy only market cannot induce investors to invest in generation field. Due to energy only market inefficiency, a supplementary algorithm is suggested to cover the mentioned defect and consequently to have adequate level of generation to meet demand in peak periods. This work tries to present a new pay as bid capacity market in which consumers compete with each other in order to obtain their adequate level of subscribed capacity. In this model, consumers bid their optimum subscribed capacity level alongside their optimum capacity price to the ISO. ISO clears the market considering the proposed capacity level from the generation side and capacity bids from the demand side. Those consumers which are accepted in the market, buy their market admitted capacity levels based on their proposed capacity prices. The generation units’ payoffs obtained from the proposed capacity market increase the investors’ incentive to invest in new power plants which results in higher available installed capacity in the time of peak load. For more transparency, two kinds of uncertainties (short-term and long-term uncertainties) are taken in to account to model the consumers and market behavior and system is simulated over a long planning horizon and obtained results are compared with two other types of markets, Energy Only and basic Capacity Subscription. The impressive results obtained from the simulation show the efficiency of the new proposed method.
    Keywords: Restructuring, capacity market, capacity subscription market, generation expansion planning
  • S.A. Hosseini, H. Askarian Abyaneh, S.H.H. Sadeghi, F. Razavi, M. Karami Pages 133-153
    The Iranian Ministry of Energy commands the Regional Electrical Companies to install DG resources at 63kV/20kV substations and at the end of 20kV lines. The first and foremost challenge in installing these resources is deciding on the optimal place and capacity of these resources. This paper is aimed to propose an appropriate algorithm for siting and sizing such resources in Bakhtar Regional Electrical Company. The proposed algorithm takes into consideration all technical and economic factors important to the company. Due to the variety of important factors in sizing and siting, this paper proposes a new method to reduce limitations and constraints of this process. Accordingly, all technical and economic factors are assigned monetarily, so violating limitations reduces considered benefits. This method increases the probability of convergence of results and accordingly is appropriate for application in actual network where there are numerous factors. Another feature of this paper is considering the parameter of earthquake for the first time and is assigned monetarily according to its devastating effects on considered parameters. Applying this parameter while sizing and siting leads to increase in distributed generation impacts in reducing customer outage in locations with high probability of earthquake. The obtained results are reported and discussed.
    Keywords: Distributed generation, siting, sizing, cost, to, benefit ratio, earthquake
  • S. Nojavan, M. Jalali, K. Zare Pages 155-165
    Application of distributed generation (DG) units in distribution networks has increased in recent years. Sizing and sitting of DG units are two important factors which should be considered, especially for reduction of power losses in distribution system. This paper presents a new approach for DG placement in distribution systems using the mixed integer nonlinear programming (MINLP). This approach determines the optimal number, sitting and sizing of DG units in both radial and meshed distribution networks with the objectives of reducing the power losses, as well as minimizing the investment and operation costs of DG units, and the monetary value of voltage stability index improvement. The performance of the proposed method is compared with the genetic algorithm (GA), particle swarm optimization (PSO), combined GA and PSO, and combined loss sensitivity factor and simulated annealing (LSFSA). Compared with the conventional methods, the proposed scheme can be applied in the meshed distribution networks as well. A 33-bus radial network and CIVANLAR meshed distribution system have been used for simulation studies. The obtained results approve the efficiency of proposed method for sitting and sizing of DG units in distribution networks.
    Keywords: DG allocation, MINLP approach, radial, mesh distribution systems, voltage stability index
  • S.A. Hosseini, H. Askarian Abyaneh, S.H.H. Sadeghi, F. Razavi, M. Karami Pages 167-182
    Microgrid presents an efficient and novel solution for integrating many new energy generating resources with traditional distribution networks. Having an appropriate protective scheme is a fundamental challenge in achieving microgrid plans. It is proven that traditional protective plans are not efficient for protecting microgrid, since the network is dynamic and the level of fault current changes continually. Accordingly, this paper presents a novel method to detect fault in microgrids. Presented plan of this paper is based on calculating harmonic impedance. Harmonic impedance can be calculated using linear analysis in frequency domain. Generally, in this plan, communicative equipment is applied to monitor the network, and a Supervisory Remote Control Unit is used for calculations and commanding. Using this controller, the proposed method would be able to use online calculation for fault detection and unlike studies which use offline data, the proposed method is not limited to a special structure. Using the proposed method, different type of faults, especially high impedance faults, are detectable and locatable. Consequently, the presented method provides many features for protective system such as selectivity and also ability to detect symmetrical, asymmetrical, and high impedance faults. In addition, fault detecting is independent from microgrid control system and hence reliability and flexibility of protection and control system increased. The presented method is applied to IEEE 14 buses test network. The obtained results are reported and discussed.
    Keywords: Micro grid protection, supervisory unit controller, harmonic impedance, fault detection
  • A. Yahi, L. Barazane Pages 183-192
    The use of micro-controllers in actuators provides extended flexibility for on-line data acquisition and sophisticated control implementation. However, attempts to utilize the excellent features of induction motor that is deemed by its strength, robustness, high torque, and relatively low cost in actuators face a fundamental control design challenge. The purpose of this paper is to introduce the synergic control theory, and apply it to design a speed controller for an induction motor and optimize the parameters of the controller to improve its responses convergence with higher performances and minimum chattering compared to sliding mode control. This paper presents technological invariant manifold based on vector control design with rotor field oriented control (RFOC) for induction motor; the design uses Synergetic Control theory to create an analytical control law which ensures asymptotic stability of the closed-loop operation, eliminate the influences of both external disturbances and parameters variations. To validate this approach, simulation study is carried out, and shows some very interesting features.
    Keywords: Induction motor, field, oriented control, synergetic control theory, electric traction, nonlinear control
  • J. Tahmoresnezhad, S. Hashemi Pages 193-207
    Transfer learning allows the knowledge transference from the source (training dataset) to target (test dataset) domain. Feature selection for transfer learning (f-MMD) is a simple and effective transfer learning method, which tackles the domain shift problem. f-MMD has good performance on small-sized datasets, but it suffers from two major issues: i) computational efficiency and predictive performance of f-MMD is challenged by the application domains with large number of examples and features, and ii) f-MMD considers the domain shift problem in fully unsupervised manner. In this paper, we propose a new approach to break down the large initial set of samples into a number of small-sized random subsets, called samplesets. Moreover, we present a feature weighting and instance clustering approach, which categorizes the original feature samplesets into the variant and invariant features. In domain shift problem, invariant features have a vital role in transferring knowledge across domains. The proposed method is called RAkET (RAndom k samplesETs), where k is a parameter that determines the size of the samplesets. Empirical evidence indicates that RAkET manages to improve substantially over f-MMD, especially in domains with large number of features and examples. We evaluate RAkET against other well-known transfer learning methods on synthetic and real world datasets.
    Keywords: Transfer learning, unsupervised domain adaptation, random samplesets, feature weighting, instance clustering
  • K. Chitra, A. Jeevanandham Pages 209-215
    This paper presents the new topology of three phase on line Uninterruptible Power Supply (UPS) by employing T-Source Inverter (TSI) with maximum constant boost Pulse Width Modulation (PWM) control and the results are compared with the conventional Uninterruptible Power Supply (UPS). The conventional UPS consists of Voltage Source Inverter (VSI) with step up transformer or DC-DC booster which decreases the efficiency and increases energy conversion cost. The proposed three phase UPS with TSI has the voltage boost capability through shoot through zero state which is not present in the conventional VSI. This proposed UPS increases the efficiency due to single stage conversion, reduces the harmonics, increases the voltage gain and reduces the voltage stress. The performance of the three phase on-line UPS with TSI is simulated in MATLAB / SIMULINK software and the results are compared with conventional UPS. The simulation and the theoretical analysis are validated with experimental results.
    Keywords: On, line UPS, T, Source Inverter, maximum constant boost, boost factor
  • G. Khademi, H. Mohammadi, M. Dehghani Pages 217-227
    Model order reduction is known as the problem of minimizing the -norm of the difference between the transfer function of the original system and the reduced one. In many papers, linear matrix inequality (LMI) approach is utilized to address the minimization problem. This paper deals with defining an extra matrix inequality constraint to guarantee that the minimum phase characteristic of the system preserves after order reduction. To overcome this, poles and zeros of the reduced system transfer function must be at left-half plane (LHP). It is very easy to apply a LMI condition to force the poles of the system to be at LHP. However, the same cannot be applied to zeroes easily. Thus, a special state-space realization of the system is introduced in a way to apply conditions on zeros of the reduced system. The method is applied to some sample examples and the simulation results verify the performance of the proposed method.
    Keywords: H∞ norm, Linear matrix inequalities, minimum phase system, model order reduction