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Showing 5 results for Faghihi
Kourosh Apornak, Dr. Soodabeh Soleymani, Dr. Faramarz Faghihi, Dr. Babak Mozafari,
Volume 9, Issue 2 (8-2020)
Abstract
As the power system restructured, new entities emerged in the electricity market, including retail electricity companies. These entities purchase electricity from the wholesale market and sell it to consumers at competitive pricing rate. With the intermediary role of these entities, it is important to adopt a proper strategy in dealing with supply and demand side because this proper strategy has a significant impact on profit or loss of the retailer. This paper presents a model to maximize the retailer profit while calculating the optimal risk limitation based on bilateral contracts, pool market, customer’s behavior and price elasticity of demand. The proposed model in the form of optimization problem solved as a nonlinear programming with SNOPT solver of GAMS software. The results of applying the proposed model show the accuracy of the results and maximize the retailer's profit in comparison with the basic model.
Hosein Fadaeeasrami, Dr. Faramarz Faghihi, Dr. Javad Olamaei, Dr. Hosein Mohamadnejad,
Volume 10, Issue 3 (12-2021)
Abstract
High pressure insulators are exposed to different environmental and climatic conditions. The interaction of environmental conditions and insulation pollution makes the insulation of the insulators themselves a suitable substrate for conducting current and leaving its effects on power systems. Knowledge of potential distribution and electric field of high voltage equipment is an important aspect of the design, operation and performance of high pressure insulators. This can be useful for detecting defects in insulation. The purpose of this study is to show the behavior of contaminated insulators under voltage. Therefore, electric field simulation and potential distribution in the vicinity of different insulation levels were discussed. Insulators are modeled in two ways: 2D, 3D and Multiphysics Comsol software analysis, which is one of the best software used in modeling for finite elements. Finally, the results of potential distribution and electric field along the insulation in different contaminated and clean conditions, which are simulated using different conductivity values, are shown.
Mrs. Maryam Faghihi Rezaei, Dr. Majid Gandomkar, Dr. Javad Nikoukar,
Volume 10, Issue 3 (12-2021)
Abstract
In this paper, the protection coordination for Digital dual-setting directional overcurrent relays (DS-DOCR) in the presence of renewable energy sources and energy storage system in the conditions of maximum and minimum fault current in the distribution network is investigated. The proposed scheme minimizes the total operating time of the relays to achieve fast protection coordination in DS-DOCR relays. In addition, to increase the flexibility in the DS-DOCR settings, the permitted range for all relay parameters such as A, B, pickup current (IP), and time dial setting (TDS) is explained in both forward and backward directions. In the proposed scheme, the operating results of DS-DOCR relays on the IEEE 9-bus distribution network in the presence of maximum penetration of photovoltaic sources (PV), wind and energy storage systems (ESSs), in maximum and minimum fault current conditions are investigated. Simulation of the study method is done in DIgSILENT Power Factory software. The numerical results indicate that the proposed solution algorithm has ideally provided the optimal values of the DS-DOCR relays setting parameters, and is capable of achieving reliable and fast protection coordination.
Yadollah Shafiei, Dr. Faramarz Faghihi, Dr. Amir Hossein Salemi, Dr. Hossein Heydari,
Volume 11, Issue 2 (9-2022)
Abstract
Outdoor insulators are usually exposed to air pollution and severe weather conditions. Therefore, studying the discharge characteristics of insulators in such conditions is manditory. Optimization of polluted composite insulators shed parameters to minimize leakage current and electric field inlensity is the subject of this paper.Validity of the results extracted from a mathematical optimization model has been checked by experimental out comes to obtain reliable values for effective parameters. In particular, optimal values for shed spacing, shed angle, and the ratio of shed overhang to shed spacing have been investigated. Inorder to reach the above- mentioned goals, an optimization tool was implemented. To set up the problem, an objective function was developed, using an existing profile for a polymeric insulator in literature. Consequently, the constraints, recommended by IEC standard were added to the model. Finally, a computer simulation was performed, based on finite elements method ((FEM)) to visualize leakage current and electric field intensity reduction, resulted from the proposed design.
Mohammad Reza Ghasemzadeh, Dr. Faramarz Faghihi, Dr. Seyed Babak Mozafari,
Volume 12, Issue 1 (5-2023)
Abstract
Today, the role of electric energy in creating social welfare and industrial development of human societies is not hidden from anyone. In recent years, comprehensive and complete laws have been compiled and implemented for the production and supply of this energy in the market. What shows up more than ever is the concern of engineers in this field for the production, transmission and uninterrupted supply of electrical energy. The use of efficient equipment with high reliability has led engineers to use gas insulated posts in transmission and distribution networks. The use of gas insulation, while reducing the dimensions, has caused a reduction in transportation costs and installation and commissioning time of this equipment. Although gas insulation equipment requires minimal repairs due to special manufacturing technology and insulation, but the reliability and proper functioning decreases as the life of this equipment increases. Often over time, partial drainage is a defect that occurs in this equipment. This event leads to insulation failure finally, which is an important quantity in assessing insulation conditions. The most common causes of partial discharge in gas substations are three factors: conductor electrode protrusion, Existence of void in insulation and free particles suspended in gas pressurized enclosure. In this paper, studies related to the factors affecting the insulation failure of GIS substations and its timely detection methods, based on the benefit of existing articles and research.
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