Sharif Digital Repository

The leads with heavy current passing through the covering plates, and the winding in a transformer, are sources of eddy current losses. Due to this loss some regions of tank wall are subject to serious local overheating. It affects the safety and reliability of this expensive bject and power delivery.Heavy current in large power transformers and special type transformers give rise to a concentrated passage of eddy currents which in turn cause high local losses and overheating in the metallic parts especially in the steel tank walls of transformer.This local overheating is dangerous for transformer oil and the solid insulations. Therefore the calculation of losses and proper design of... 

Proliferation of distributed energy resources and the developing of smart grid concepts are of a great importance. This, however, influences the future of power systems and necessitates more studies in order to cope with the changes. In this regard, uncontrollability issues are arised by introducing the renewable energy resources in the power systems. To address this issue, energy storage systems are used to mitigate negative consequences of using renewable energy resources. Accordingly, in this thesis, a new framework for determining the capacity and location of the energy storage systems is proposed. In addition, reconfiguration of distribution network is also concerned in order to... 

Renewable energy resources, e.g. wind, solar and geothermal, experience rapid progresses in electric power industry all over the world. So, it becomes essential that these free-emission electrical energy resources be integrated in the existing generating capacity planning procedures. On the other hand, the uncertain and intermittent nature of these energies has led to some problems in their integration in power systems. The reserve requirement in a renewable-based power system is a main challenge, which has to be addressed properly. In this way, this research presents an analytical approach, based on the modified PJM method, to quantify the risk of renewable energies commitment during the... 

Over the last few years, several economical and environmental reasons have caused many countries throughout the world to plan to replace conventional gasoline vehicles with different types of electric vehicles, and hence, it is anticipated that using these vehicles will quickly be developed in near future. Widespread use of electric vehicles calls for a comprehensive network of easily accessible charging stations being capable of replenishing their batteries. In this regard, municipal public parking decks, because of their characteristics, can be considered as proper candidates for installing charging equipment. However, as a large number of electric vehicles can be parked at a public... 

Considering the high penetration of renewable energy resources in modern power systems, independent system operator faces considerable uncertainty and variability in the system under supervision. In this regard, determining and providing the appropriate amount of operational reserve is critical to overcoming uncertainty and variability to have reliable system performance. In practice, power system operators prefer to use deterministic approaches to schedule operational reserve. Such approaches have benefits in simplicity and fast calculations. Nevertheless, increasing share of renewable resources causes a considerable error in these approaches. Therefore, many researchers have proposed... 

Reward-penalty schemes are known as the most effective tools to regulate the service quality. This thesis tries to design a comprehensive reward-penalty scheme to properly motivate electricity distribution companies (DisCos) to improve the reliability and reduce the energy losses in their networks using Distributed Generation (DG) Resources. So, as the first step, the designing methods of reward-penalty scheme (RPS) and their advantage and disadvantages are introduced, and also a method based on concept of the Yaredestic theory is proposed. The proposed method uses the Fuzzy clustering and is able to set the parameters of RPS in a fair and efficient way. The proposed RPS is implemented on... 

As it is obvious from the name of this study, the goal of doing this study is the feasibility study of southern shores of Iran for building an artificial energy island for and designing it. In this project by studying seven points coastwise of southern Iran and defining the criterions and scoring the points, the Chabahar was determined as the best place for erecting the artificial energy island. With respect to the environmental condition of the chosen point and modeling in software ANSYS, the structure of the artificial energy island has been studied and the type, geometric shape, area, trough, and the setting of the anchoring system has determined. As a result of these efforts, a hexagon... 

Till today types of demand response program have been identified as one of the most effective and usefull programs in order to the energy efficient consumption and followed by, improving the network's reliability. Also some of these plans have reduced the risk of the retailers and as much as possible prevent the likely loss of these companies at the high energy tariffs times. The required for doing some of these types of plans is investing on various parts like infrastructure mutual relationships between retailers and customer and also smart meters which will require valuation. Till now so many various ways have been done for valuation on types of demand response program plans. This thesis... 

Electricity distribution systems are dynamically expanded in anticipation of new demands. Cost and reliability are the most important factors in finding the optimal plans for network expansion. Recently, implementation of incentive reliability regulations has accentuated the role of reliability considerations in distribution systems studies. This is because such incentive schemes create a direct link between distribution companies' revenues and their service reliability. Thus, these schemes have changed the role of reliability from a technical constraint to an economic factor. In this occasion, distribution companies require new techniques to incorporate the effects of incentive reliability... 

The purpose of this thesis is the presentation of an outage management scheme in a multi-microgrids system with a decentralized structure. The proposed method is designed in a two-step method to prevent damage to all microgrids and network components due to blackouts. In the first stage of this scheme, each microgrid alone provides its required power or curtails load due to the power deficiency. In the second stage, microgrids exchange power in a transactive energy environment, which is one of the new changes in active distribution systems with participation in market and price bidding, and all players of this market earn profit from their exchanges. In this case, the curtailed load will be... 

In recent decades, bio-inspired design has become a common approach among engineers. Research and study of biological systems show that these systems are very efficient and consume the least amount of energy in a definite process. Specifically, marine mammals and fishes are great sources of inspiration. As an example, recently vertical axis wind turbine farms have been designed and constructed inspired by schools of fish, to produce more electricity. Boxfishes (Teleostei: Ostraciidae) are known for their hydrodynamic stability and relatively low drag coefficient. Highly maneuverable underwater robots have been designed according to morphology of boxfishes. Furthermore, Mercedes-Benz has... 

In recent years, the penetration of renewable energy sources (RESs) in the distribution networks has faced their operation with new problems. Therefore, many studies have been conducted in this field to effectively operate distribution networks by introducing multi-microgrid (MG) structures, decentralized management methods, and the concept of transactive energy. In this regard, in this thesis, a decentralized structure based on the transactive energy is presented for optimal management of the distribution network using the alternating direction method of multipliers (ADMM) with taking the technical limitations into account. As a result, MGs will be able to exchange energy directly with... 

Nowadays, the development of renewable energy sources is in line with the increasing capacity and installation of wind energy resources. Wind turbines, due to their installation in harsh areas, have high maintenance and repair costs, which is one of the main challenges for their further development. Given the high costs of repairs, predicting faults and planning for optimal maintenance can optimize performance and extend the useful life of the turbine. The aim of this research is to provide an approach to predict faults in wind turbines using data from the control and monitoring system. This data includes various parameters such as wind speed, output power, temperature of the generator... 

Dynamic increasing amplitude and period (DIAP) [1] is a time-domain analysis methodology developed based on endurance time (ET) analysis method [2], which can be used to evaluate the response of marine structures when encounters a continuous loading, such as storm conditions. In this method, instead of using separate records with different intensities, a single loading record with an increasing intensity over time is used for structural analysis. The ability to enter spectral concepts, considering the effects of waves with different frequencies and amplitudes, taking into account the effects of randomness of waves and the possibility of short duration analysis are some of the specific... 

In majority of the (standalone or grid-connected) PV Systems, predefined rule-based algorithms are utilized in order to manage and control the flow of power. The function of these algorithms is to send the generated energy from solar panels either to load for consumption, or to battery for storage, or to the grid for sale. Their performance is based on predefined instructions and regardless of load change and consumption patterns. Therefore the total efficiency of these systems depend greately upon individual user’s load type and consumption pattern. In current research, an optimum and dynamic energy management algorithm is proposed using dynamic programming (DP) method, in order to increase... 

The necessity of electrical energy, high cost of big power plants and high voltage transmission lines and also progressing of restructuring science has lead to the increasing of tendency to use the distributed generation in electrical industry. Among of different types of distributed generations, fuel cell power plants because of many advantages such as high efficiency, low emission, modular structure and ect., have a high potential to be used in power systems. The fuel cells produce electrical energy by chemical reactions. Due to the necessity of having the knowledge related to the chemical reaction which are effective on fuel cell, to study the fuel cell performance, this type of... 

With the increasing penetration of renewable energies as distributed generation (DG) in power systems, technical problems arise in both distribution and transmission system level. Voltage rise is the main barrier for connection of DGs in rural areas, while excessive reactive power demand from transmission system is the major concern for Transmission System Operators (TSO). Here, a centralized control scheme based on the Smart Grid is proposed to reduce the impact on the transmission system voltages and improve its stability, while mitigating the voltage rise issue in the distribution network. Reactive power output of DGs, substation capacitors and tap setting of transmission transformer are... 

Based on codification and implementation of regulations of supporting from development of distributed generation sources, it is expected that in future years, investment in distributed generation scheme will be welcomed by private investors impressively. Under this circumstances, distribution Company will be faced with new chances for improving quality level of their services and optimal management of penalty-reward schemes. Penalty-reward schemes is set by legislator for distribution Company in order to improve their network. One of the pioneer ways is using distributed generators. So first, distribution Companies have to find optimum places for using these generators and in the second step... 

The integration of renewable energy sources introduces several issues including islanding operation. Therefore, Islanding phenomenon should be detected by a fast and reliable islanding detection method. In this thesis an intelligent-based approach is proposed to detect islanding state for Photovoltaic (PV) and Doubly Fed Induction Generator (DFIG) units. Decision tree classification algorithm is chosen as weak classifier and by Adaptive Boosting (AdaBoost), detection accuracy is improved. 16 features are employed to construct feature vectors. Because of intermittency of renewable electricity generation, different states for PV and DFIG generation are assumed. Probable events are simulated...