Research paper
Y. Babaei Shahmars; J. Salehi; N. Taghizadegan kalantari
Abstract
The integration of the distributed energy resources into a single entity can do with virtual power plants. VPP is a cluster of dispatchable and non- dispatchable resource with flexible loads which distributed in allover the grid that aggregated and acts as a unique power plant. Flexible load is able ...
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The integration of the distributed energy resources into a single entity can do with virtual power plants. VPP is a cluster of dispatchable and non- dispatchable resource with flexible loads which distributed in allover the grid that aggregated and acts as a unique power plant. Flexible load is able to change the consumption so demand response program is applied to use them to improvement of the power system performance. Virtual power plant generation has uncertainty and it make hard to schedule the VPP. To deal this matter Information gap decision theory hint us to optimal schedule of the VPP. To show the effects of VPP and DRP on power system operation cost a bi-level unit commitment with regard the VPPs and DRP is solved in modified IEEE 24 bus reliability test system. Results in presence of VPP and DRP in both IGDT strategies are compared with disregard VPP and DRP and effectiveness of the proposed model is reflected.
Research paper
A. Bagheri; A. Rabiee; S. Galavani; H. Yassami; A. Moeini
Abstract
Transmission lines switching and tap adjustment of power transformers are short-term alternatives to enhance the flexibility of power system operation. By a proper implementation of these alternatives, the operational problems such as lines congestion, bus voltage violations and excessive power losses ...
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Transmission lines switching and tap adjustment of power transformers are short-term alternatives to enhance the flexibility of power system operation. By a proper implementation of these alternatives, the operational problems such as lines congestion, bus voltage violations and excessive power losses can be alleviated. Traditionally, these two alternatives are applied separately due to the complexity of their simultaneous implementation as well as their coordination. In this paper, a DIgSILENT-based improved particle swarm optimization (IPSO) algorithm is proposed to implement the transmission switching and coordinated voltage control of power transformers, concurrently. The IPSO is implemented in DPL environment of Powerfactory-DIgSILENT, as a powerful software package commonly used by the electrical utilities. The proposed approach is applied to IEEE-14 bus system and the real transmission network of Zanjan Regional Electric Company (ZREC) located in Iran, in different scenarios considering all the existing practical constraints. The obtained results verify the effectiveness of the presented approach.
Research paper
A. Samarat; B. MEHTA; S. Joshi
Abstract
In view of global targets to expurgate the carbon foot prints, presently major focus is on integrating prosumer renewable energy sources (RES). This has caught more interest in studying the impacts of AC and DC micro grid. Looking at the advantages of power transformers for stepping up and down the voltages, ...
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In view of global targets to expurgate the carbon foot prints, presently major focus is on integrating prosumer renewable energy sources (RES). This has caught more interest in studying the impacts of AC and DC micro grid. Looking at the advantages of power transformers for stepping up and down the voltages, AC grids seem favorable for transmitting power over long distances, but AC grids are also often subjected to difficulties associated with them such as frequency dip, voltage drop due to line impedance, skin effect and Ferranti effect etc. Most of the sources and loads, particularly the renewables like solar, battery etc., in a micro grid are basically DC in nature and their operating voltages are low. Considering the conversion losses and transformer cost combined with problems of AC grid, DC micro grids are catching attention and their analysis is thus required. This paper presents the controls of various types of distributed generation sources (DGs) including renewable energy sources (RES) so as to integrate them to form a micro-grid. The AC and DC micro-grid models have been developed and its performance is assessed. Stability analysis is performed on both AC and DC micro-grid during permanent faults, temporary faults and sudden load variations to have a comparative outcome for selection of a better micro-grid.
Research paper
A. Mohammadi; M.A. Shamsi Nejad
Abstract
This paper investigates a fundamental issue in AC-DC rectifiers that are specifically used as charger for electric vehicle (EV), i.e. the total harmonic distortion (THD) of input current waveforms. Firstly, the topology of two-stage charger along with the corresponding control scheme is reviewed. Then, ...
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This paper investigates a fundamental issue in AC-DC rectifiers that are specifically used as charger for electric vehicle (EV), i.e. the total harmonic distortion (THD) of input current waveforms. Firstly, the topology of two-stage charger along with the corresponding control scheme is reviewed. Then, the research gap namely high harmonic distortion of input current is identified and analyzed. A revision of the conventional control method with the aid of virtual resistant is proposed and investigated from the circuit perspectives. Finally, simulation results are delivered to validate the analysis and the reduction of THD in the input current waveform. this is proposed method, the steady state is studied.
Research paper
A. Afraz; B. Rezaeealam; S.J. SeyedShenava; M. Doostizadeh
Abstract
The scheduling of electricity distribution networks has changed dramatically by integrating renewable energy sources (RES) as well as energy storage systems (ESS). The sizing and placement of these resources have significant technical and economic impacts on the network. Whereas the utilization of these ...
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The scheduling of electricity distribution networks has changed dramatically by integrating renewable energy sources (RES) as well as energy storage systems (ESS). The sizing and placement of these resources have significant technical and economic impacts on the network. Whereas the utilization of these resources in the active distribution network (ADN) has several advantages, accordingly, the undesirable effects of these resources on ADN need to be analyzed and recovered. In this paper, a hybrid ADN, including wind, PV, and ESS, is investigated in 33 buses IEEE standard system. First of all, optimal energy management and sizing of the RES and ESS are the purposes. Secondly, as demand response (DR) is another substantial option in ADNs for regulating production and demand, an incentive-based DR program is applied for peak shaving. Forasmuch as this method has uncertainty, due to its dependence on customer consumption patterns, the use of inappropriate incentives will not be able to stimulate customers to reduce their consumption at peak times. Accordingly, the climatic condition uncertainty, which is another factor of variability on the production side, is minimized in this paper by relying on the Monte Carlo estimation method. Besides, the optimization problem, which is formulated as optimal programming, is solved to calculate the optimal size and place of each RESs and ESS conditions regarding power loss, voltage profile, and cost optimization. Furthermore, a geometric, energy source and network capacity, and cost constraints, are considered. The results confirm the effectiveness of proposed energy management and cost reduction in the studied test system.
Applied paper
S. Razmjou
Abstract
As a result of rapid global urbanization, energy and environmental sustainability are becoming increasingly significant. According to the Rail Transport and Environment Report published by the International Union of Railways in 2015, energy used in the transportation sector accounts for ...
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As a result of rapid global urbanization, energy and environmental sustainability are becoming increasingly significant. According to the Rail Transport and Environment Report published by the International Union of Railways in 2015, energy used in the transportation sector accounts for approximately 32% of final energy consumption in the EU. Railway, representing over 8.5% of the total traffic in volume, shares less than 2% of the transport energy consumption. Railway plays an important role in reducing energy usage and CO2 emissions, compared with other transport modes such as road transport. However, despite the inherent efficiency, the energy used by the rail industry is still high, making the study of railway energy efficiency of global importance. Therefore, in this paper, the development of the comprehensive simulator software for DC-fed railway systems is demonstrated. In the proposed MATLAB based software, the train movement model and railway power network model are integrated into the simulator. This energy simulator can calculate the energy flow of the whole system according to multiple-train driving controls and timetables. Finally, the results of simulations for a standard Railway system are compared to valid references.
Research paper
A. Ghaedi; H. Gorginpour; E. Noroozi
Abstract
In today's power systems, the use of methods that can increase the energy efficiency and reduce the cost of the generated energy has received much attention. One of these methods is the use of the combined heat and power (CHP) plants that simultaneously can generate the electric and thermal powers. In ...
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In today's power systems, the use of methods that can increase the energy efficiency and reduce the cost of the generated energy has received much attention. One of these methods is the use of the combined heat and power (CHP) plants that simultaneously can generate the electric and thermal powers. In the conventional thermal power plants, the thermal energy of the working fluid coming out from the turbine is dissipated that result in low efficiency. However, it can be used for the heating purposes in the CHP units that result in the high efficiency of these plants. Due to the wide use of the CHP units in the power system, different aspects of the power system such as operation may be affected that must be studied. In this paper, the study of the power system operation integrated with the CHP plants is performed. For this purpose, the PJM method that considers the reliability-based indices such as unit commitment risk is utilized. Moreover, a four-state reliability model is developed different types of the CHP units including gas turbine, steam turbine, reciprocating engine, micro-turbine and fuel cell technologies. In the proposed model, both the failure of composed components and the participation of the CHP units in the thermal power generation are considered. To determine the probabilities of different states of the proposed model, matrix multiplication technique is used. Based on the PJM technique, the numerical results associated to the operation studies of the RBTS and IEEE-RTS that are given and the unit commitment risk and the required spinning reserve of these systems calculated considering the effect of the CHP units.
Research paper
H. Gorginpour
Abstract
Optimal Design of electrical machines using population-based optimization algorithms needs computationally fast model for evaluating the performance characteristics from design data, i.e. geometric dimensions, winding layouts, material properties. The Electric Equivalent Circuit (EEC) is a simple and ...
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Optimal Design of electrical machines using population-based optimization algorithms needs computationally fast model for evaluating the performance characteristics from design data, i.e. geometric dimensions, winding layouts, material properties. The Electric Equivalent Circuit (EEC) is a simple and appropriate model with acceptable accuracy to be incorporated in the design procedure. In this paper, an analytical approach is presented for calculating the EEC parameters of large non-salient pole synchronous generator based on winding-function method. Although the synchronous generator is well recognized, calculation of its dynamic EEC parameters is not reported in previous studies. Special issues of high-rated industrial synchronous generators are considered such as rotor slots with different dimensions, rotor sub-slots, the damper winding which is created from rotor wedges and retaining rings, saturation of magnetic flux routes in d-q-axis and stator core stacking. The connections of damper windings in d-q-axis and definitions of turn-ratios to refer the parameters to the stator-winding side are of novelties of the research. The calculated parameters for a 200MVA power-plant generator are compared with the experimentally obtained parameters. The results of EEC analysis of the studied machine have acceptable coincidence with the experimental and 2D finite-element simulation results, which proves the validity of the proposed method.
