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Energy Management and Technology - Volume:5 Issue: 1, Winter 2021

Journal of Energy Management and Technology
Volume:5 Issue: 1, Winter 2021

  • تاریخ انتشار: 1399/05/23
  • تعداد عناوین: 7
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  • Ali Bakhshi, Alireza Alfi * Pages 1-7
    Reliability and robustness are two main goals in developing control systems for wind turbine  (WT) due to the existence of different sources, such as unknown malfunctions or faults. Their ignorance can significantly jeopardize the system  performance and even stability. This paper presents a new active fault tolerant control (FTC) for WT system considering the fault of pitch  system. The nonlinear model of WT is constructed in the form of strict-feedback in order to design an appropriate FTC-based backstepping control law. The mechanism of fault detection is based on a modified nonlinear fuzzy state observer, where the estimation of unknown terms is realized via fuzzy approximators, incorporated in the fuzzy observer. Accordingly, the rotor speed of the system can follow the desired reference in the presence of an actuator fault. The robust behavior, fast response, and acceptable tracking performance together with the model-free structure are the important properties of the proposed FTC-based controller. The stability of the overall closed-loop system, including the controller and the observer, is derived by the Lyapunov method. Simulation results highlight the superior performance of the proposed control method.
    Keywords: Wind Turbine, Fault Tolerant Control, Backstepping method, Fuzzy observer, Stability
  • Masoumeh Karimi, Sajad Najafi Ravadanegh *, Mahmoud Reza Haghifam Pages 8-16
    Vulnerability mitigation and redundancy improvement are of the solutions for creating resilient distribution networks that aim to prevent the uncontrollable outage propagation. In this paper, a comparative study is proposed for optimal feeder routing problem and HV substation placement considering cost and resilience. In the first case, the network is planned based on cost minimization, and then the proposed resilience index is calculated for the planned network. While in the second case, the network is designed based on resilience enhancement, and afterward, the planned network cost is calculated. In the case of resilient-based planning, the studied area is divided into small sites with different wind speed to evaluate the geospatial characteristics of a hurricane. A fragility index is calculated for each distribution network component located at each site. Furthermore, in this paper, the effect of HV substation number as redundancy improvement is considered in cost and resilient based planning performance. Results show that with increasing of the HV substation number, the cost of feeder routing is less increased. While it has more effect on the improvement of the resilient performance index. The obtained results validate the feasibility and efficiency of the proposed method.
    Keywords: Network planning, Resilience, Distribution network, disaster, geospatial map, Fragility
  • Farnaz Jamadi, Zahra Salahshoor Mottaghi, Mohammad Javad Mahmoodabadi *, Taiebeh Zohari, Ahmad Bagheri Pages 17-22
    Oil is one of the most precious source of energy for the world and has an important role in the global economy. Therefore, the long-term prediction of the crude oil price is an important issue in economy and industry especially in recent years. The purpose of this paper is introducing a new Particle Swarm Optimization (PSO) algorithm to forecast the oil prices. Indeed, the PSO is a population-based optimization method inspired by the flocking behavior of birds. Its original version suffers from tripping in local minima. Here, the PSO is enhanced utilizing a convergence operator, an adaptive inertia weight and linear acceleration coefficients. The numerical results of mathematical test functions, obtained by the proposed algorithm and other variants of the PSO elucidate that this new approach operates competently in terms of the convergence speed, global optimality and solution accuracy. Furthermore, the effective variables on the long-term crude oil price are regarded and utilized as input data to the algorithm. The objective function of the optimization process considered in this research study is the summation of the square of the difference between the actual and the predicted oil prices. Finally, the long-term crude oil prices are accurately forecasted by the proposed strategy which proves its reliability and competence.
    Keywords: Particle Swarm Optimization, Long-term prediction, crude oil price, Mathematical test functions
  • Hamid Samadi, Mahmoud Ebadian, Saeedreza Goldani * Pages 23-34
    Hierarchical control, which includes centralized and decentralized control systems, is a convenient method to control microgrids. The optimal operation of a microgrid from an economic point of view is the duty of the third level of hierarchical control. In the market model with a uniform payment method, the optimal economic dispatch of active power is based on the equality of marginal utility of the microgrid controllable resources. A dynamic population dispatch is applied to a real-time market to implement this equality. The share of each source from the demand is proportional to the value of its fitness. The fitness of each source depends on its rated power, the cost factor and penalty factor. To calculate the penalty factor, the Jacobian and numerical methods are compared. By calculating the marginal utility using a dynamic power dispatch approach and knowledge of market price by the main power grid (MPG), the path of energy exchange between the microgrid and the MPG is specified. The microgrid participation in the ancillary services market and the profit of microgrid in active or reactive power sales are also investigated. A 14-bus radial network with resistive lines and five different controllable sources are chosen in this paper. A real-time approach is presented for optimal economic control of microgrids with the objective of maximizing their profit in the real-time market.
    Keywords: microgrid, Dynamic optimal control, Real-time market, Losses
  • Ali Akhavein *, Mojtaba Najafi Pages 35-42
    There is an increasing trend in consideration of the electricity-supply quality in modern power systems. One of the quality-related aspects is the desired level of reliability at the points of electrical-energy consumption or load points. In this regard, the system operator needs to evaluate the impact of system components on the reliability at the considered load points. “Reliability importance” is a quantitative index in order to measure this impact. The reliability importance measure in most of the conventional methods is on the basis of the risk sensitivity analysis. Such an analysis imposes prohibitive computational burden in large power systems. Considering these points, this paper proposes an approach to evaluate the reliability importance which is not suffered from the immense computational burden. The proposed method determines reliability importance of the electrical-energy producers or generators from the consumers or load points perspective in a selected area of the power system. In order to do so, generators are ranked according to their impact on the mentioned area. This impact is measured on the basis of the effect of generators on power-flows in the lines which cross boundary of the selected area. Capacity and unavailability of the generators are also considered in the ranking calculations. Applicability and computational efficiency of the proposed method is validated through studies conducted on two test systems.
    Keywords: Reliability importance, generator, Load point
  • Afshin Mahboubkhah, Vahid Talavat*, Mojtaba Beiraghi Pages 43-50

    Directional overcurrent relays are used to protect transmission lines against short circuits. Reducing the total operating time of relays has always been a challenge for protection engineers. For this purpose, various optimization algorithms have been introduced, some of which are based on multi-objective optimization. The objective functions of multi-objective algorithms must have the Pareto optimality property, which it’s ignoring is one of the drawbacks of previous studies. In this paper, new objective functions are proposed for a multi-objective optimization problem. To solve the optimization problem, the Multi-object PSO (MOPSO)algorithm is applied with small but effective changes to get the fastest settings of relays. These changes include a leader selection method, a removal method of repository surplus members, and a new velocity vector for particles based on the value of the objective function in the previous iteration. The proposed algorithm is evaluated in IEEE 30-bus network and compared with the standard MOPSO. There is also a comparison with the recent outstanding papers. The proposed method, compared to the 15 algorithms of other papers, results in the lowest total operating time of relays with a 7% reduction.

    Keywords: MOPSO, Optimization, Pareto-ranking, IEEE 30-bus network
  • Sara Sadat Ghasemi, Hamdi Abdi* Pages 51-61

    With the increased use of wind power in power systems, the necessity of revision of conventional deterministic approaches is indisputable. Presenting new and effective methods based on uncertainty modeling is greatly emphasized. In this paper, a new method for investigating the robust security constrained-optimal power flow (RSCOPF) is proposed, which is not only able to comply with security constraints but also robust to the uncertainty of electrical demand loads and wind power generation. The proposed approach is based on the definition of uncertain loads and wind power generation and uses the Taguchi orthogonal array technique (TOAT), for the first time, a technique which is adopted to solve the RSCOPF by applying the alternating current power flow (ACPF) and particle swarm optimization (PSO) algorithm. Also, some security analyses are presented to introduce the most critical lines and generation units whose loss imposes the highest operating costs on the network. The case study simulation on the IEEE 14-bus system using MATLAB software demonstrates the ability of the proposed algorithm.

    Keywords: Taguchi orthogonal arrays technique, AC optimal power flow, Security-constrained, Uncertainty, Robust