Sharif Digital Repository

Restructuring and privatization in power system such as any industry leads to better market operation and more social welfare. Since two decade the power system in many countries have changed from monopoly to free market. In a restructured network the technical and economical aspects should be considered together. Ancillary services are needed for any power system to be operated in an optimal and secure manner. Reactive power and voltage regulation is one of the most important ancillary services in the network. this service should be supplied by its providers through a competitive market and system operator determines the optimal dispatch among different bids. The cost of purchasing reactive... 

CHP (Combined Heat and Power) generates electricity and thermal energy simultaneously from input fuel. Since it has high energy efficiency and low installation time, it is an appropriate approach in energy management of residential complexes. In this project, stochastic programming based on Monte Carlo approach is used to handle uncertainties in the optimal sizing of CHP for residential complexes. Availability of CHP, boiler and AC bus as well as the electrical and thermal load forecast errors are considered as stochastic variables. Minimizing system total cost considering the probability of each scenario obtained from the scenario reduction algorithm is the objective function. The system... 

The process of deregulation that has involved electricity many markets has introduced several new interesting research topics in power system area. This thesis addresses one of the most fascinating issues among them: the study of distributed generation both renewable and conventional integration in distribution networks. From the distribution network operator (DNO)'s point of view, it is of interest to develop a comprehensive methodology which considers various distributed generation technologies as an option for supplying the demand in distribution networks. In this thesis, the planning problem has been multi-objectively modeled. This will help the planner in decision making while knowing... 

Since 1980s the electricity market has been gradually evolving from a monopoly market into a liberalized one for encouraging competition and improving efficiency. This brings the opportunity for generation companies (Gencos) to make more profits while embracing more risks of not being dispatched. Therefore, it has become a core interest for the Gencos to develop optimal bidding strategies to maximize the profits and minimize the risks while participating in such a competitive market. Error of determining day-ahead electricity price is one of the sources of the risk. Energy price has a high impact on bidding strategy optimization process. So it should be determined with low error which is not... 

Losses are unavoidable in any parts of power systems, from generation to receiving nodes and occur in transmission and distribution networks. However, the main loss component is produced in distribution networks. Energy losses in distribution networks are about 70% of technological transport energy losses.
Energy losses in distribution networks are an important indicator for the planning and operation of the system. A fast, reliable and accurate energy loss calculation method is required for optimal operation of the distribution networks.
Energy loss depends on network's operating conditions. Loads values and loads factors are time variables; therefore, methods based on probability... 

Uncertain fuel prices and also global climate changes are accompanied by some state initiatives such as renewable portfolio standards (RPS). This has caused a fast growth in the amount of renewable energy installed worldwide especially wind energy over last decades. However, the intrinsic characteristics of wind farms output power, i.e. intermittency and volatility of wind speed along with being non-dispatchable in output generation of wind turbine raises many new technical and financial challenges for power system operators and planners. Up to these issues, large level of wind power penetration causes a growing concern in wind energy curtailment issue which the wind farm’s operator may be... 

Electricity retailers are one of the power market entities which act as an intermediary between the producers in the wholesale market and the consumers in the retail side. The main task of a retailer in the power market is to set contract with the consumers to supply their electricity during a pre-specified time period and to participate in the wholesale market to supply the electricity needed by its costomers. Retailer’s contract with its customers may be a simple contract with a fixed pre-determined energy price or include some more complicated feathures such as involvement of a percent of green energy or variable price and demand response contracts. Moreover, retailer can supply its... 

In recent years, due to restructuring in the electric power industry, distributed generation has become one of the most important subjects and DGs and renewable energy sources have been increasingly expected as a supplement and an alternative to a conventional large scale central power system. their success depends not only on the distribution of the available renewable energy sources in a region but also on the power grids connectable capacity in the area. Photovoltaic system is one of the best RESs for residential electricity supply because it is noiseless and solar power is widely available and households can use it via photovoltaic cells in their homes. There are two major problems... 

This Thesis presents a new approach for determining the day-ahead bidding strategies of a hybrid electric energy company. The company has both energy generation and energy retailing businesses in a competitive electricity market. Demand response programs are also considered in the retail side of the company in order to hedge the risk of participation in wholesale market. Price-taker and price maker companies are considered in this thesis separateky.For the price-taker hybrid structure, the predivtion of day-ahead prices are used to evaluate the optimum bidding and offering strategies. Also, day-ahead market price uncertainty is modeled, using non-probabilistic Information Gap Decision Theory... 

Renewable energy deployment through distributed energy resources is among the central goals of future power systems. Microgrids have proven to be an economically viable soloution for distributed energy resources integration into power system and benefit the customers with uninterrupted power supply. In this context provisional microgrids have been introduced with the main goal of rapid renewable energy sources deployment. Since a considerable portion of renewable enegy resources as well as residential loads are DC and this portion is expected to grow even further, hybrid AC/DC design of provisional microgrids can improve both efficiency and economic benefit by optimal arrangement of AC/DC... 

Due to the increasing influence of distribution generation , their effect in planning can't be ignord , especially solar panels ,which are incresing rapidly. The main purpose of this thesis is to an active distribution network that annually load bus and the amount of photovoltaic production in it increases and plan dynamically. In the planning that is done , uncertanty in the amount comsumption load and uncertanty in the pattern of sunlight and also annual innterest rates in the classical system we have planned by optimizing the network expansion costs , in addition to supplying the load bus, we can keep the voltage drop bus and line filling within the allowable . To do this , we considered... 

In a deregulated environment of power distribution industry, a comprehensive economic evaluation for the implementation of distribution automation systems is inevitable. It plays a key role in enabling distribution companies to achieve their business goals. In this thesis, a dynamic economic evaluation is presented to provide a comprehensive perception of automation intensity level and investment plan, for maximizing the utility profit and obtaining the desired payback period. Using the presented methodology in this thesis and system dynamics approach, it is efficiently possible to deal with variation of the economic parameters such as the interest rate, inflation rate, energy supply cost,... 

The competition between producers and the contracts issues between the producers and consumers of electrical energy in restructured power systems might cause on unwanted increase in power interchange beyond transmission lines capacity. If the power interchange is not well-managed, it would often cause overloads in specific path. This phenomenon is termed as lines congestion. The major goal of congestion management is to create a set of rules that ensure sufficient control over producers and consumers to maintain an acceptable level of power system security and reliability in the time of limitation of transmission network with maximizing economic market efficiency. As FACTS devices provide... 

Nowadays, with the development of the generation and storage technologies of electrical energy, increasing attention to environmental issues, and interest in improving the reliability of electrical energy distribution networks, the motivation to develop the distribution networks from pssive to active mode. Although, the utilizing of electrical energy storage systems (EESs) made technical and economic analysis of power system more complicated, but some of these challenges have faciliated by microgrids. Indeed, microgrids, as low voltage and medium voltage networks, can provide a set of significant benefits at the level of distribution networks by improving energy efficiency, power quality,... 

The fast growth of technologies, most of which depend on natural sources of energy, has resulted in colossal fossil fuel consumption. In this regard, many solutions have been suggested to alleviate the side effects such as air pollution and global warming. Among these solutions, mobile storages like electric vehicles (EVs) and renewable generations have grown significantly due to being more applicable. The uncoordinated operation and uncertain nature of these distributed energy resources (DERs) can bring forward new challenges and issues to the power system operators. Thus, in many cases, it is more efficient to co-operate them in a hybrid system. In this thesis, we address a virtual power plant... 

In order to reduce damage caused by power outages on rare events that lead to long-term disconnection of microgrid from utility grid, isolated mode performance of microgrids including wind and hudro turbines with energy storage systems is considered in this study. Using wind energy as a renewable resource is considered as an appropriate choice for power production in microgrids. However, the uncertainty in wind turbines power generation is something challenging. The existence of water resources near the wind farms causes a special opportunity for operation of these resources along with wind turbines. This thesis aimed at balancing energy supply and demand in island mode of microgrid,... 

The analysis of electrical energy consumption parameters such as rate and amount of consumption, plays an important role in the planning of power systems. Because the dynamic analysis and evaluation of these parameters provides a detailed forecast of consumption and power system load. these forecasts is given to planners and engineers as the input of power system planning .Given that the electrical energy consumption system can be thought as a dynamic system, System Dynamics (SD) method would be very appropriate for modeling and analyzing its behavior. In this thesis, based on the SD and by means of dynamic loops, a comprehensive dynamic system for electrical energy is introduced. So the... 

Cogeneration or combined heat and power (CHP) which simultaneously produces electricity and heat energy from sequential use of single fuel source, has been introduced increasingly for industrial, commercial and residential applications due to its high energy efficiency. While the capital costs of CHP systems are comparatively higher than the conventional systems, their proper selection and optimal sizing and also optimal operation could result in shorter capital recovery period and lower cost of energy supply. Essentially the technical, economic and environmental performances of CHP system are closely dependent on its design and operation strategy. This project presents an optimization... 

One of the topics that has been given great consideration after restructuring and smart grid emergence, is loss management. This subject is specifically important in distribution systems, which have been reported to have 70% of the total loss in power systems. In this thesis, distribution loss is studied and its affecting factors are analyzed. Then loss optimization and loss cost allocation to distribution consumers are studeid. In order to acheive these two goals, it is neccessary for the distribution system to have the capabilities of a smart grid. The subjectof distribution reconfiguration is duiscussed as one of the loss reduction methods. Traditional reconfiguration problem trend...