Sharif Digital Repository

Increasing demand in power systems necessitates the Generation Expansion Planning (GEP) which is to determine the type, size, and location of new generating units in a planning horizon. The final solution of GEP is based on the minimum cost and/or optimum reliability taking into account various constraints such as capacity of units and lines, operating constraints, and budget restrictions. This paper presents a model based on scenarios for generation expansion planning and units retirement decision. The proposed model could be used by vertically integrated utilities as well as the ISOs in electricity markets to obtain generation expansion schemes. In this approach, uncertainty of units are... 

Nowadays, considering the dependence of the life quality to the electric energy, exhaustion of the existing facilities in the distribution networks, and restructuring of the electric industry, the reliability improvement turns out to be one of the most important considerations in order to reducing the operational cost. Furthermore, the expansion of existing networks, substitution, and refinement of the exhausted facilities for improving the reliability can lead to remarkable expenses. Considering the limitations of budgets of distribution network companies, these plans cannot be put into practice. Therefore, operators and planners of this industry have to find ways to operate the existing... 

Residential demand response is an appropriate control tool for improving system reliability. This project intends to establish a model to activate residential demand response to improve distribution network reliability. Two centralized and decentralized models are proposed. The models aim at minimizing the damage cost imposed by load curtailments following unexpected events. In the models, it is supposed that distribution system operator (DSO) and responsive customers already signed a contract authorizing the DSO alters the operation of responsive appliances whenever system reliability is jeopardized. In centralized framework, Responsive customers deliver the technical data of their... 

Plug-in hybrid electric vehicles (PHEVs) present environmental and energy security advantages versus conventional gasoline vehicles. In the near future, the number of PHEVs will likely grow significantly in the world. In spite of the aforementioned advantages, the connection of PHEVs to the power grid may create a series of new challenges for electric utilities. If PHEV penetration exceeds a certain amount it can endanger power system security. In this research, a new charging control scheme which includes both the customer and grid acquiescence is presented. Optimal charging algorithm is developed which minimizes the electrical charging payment of customers. The optimization problem in this... 

The current state of restructuring in the electric power industry has forced power companies to maintain and enhance service reliability and quality while controlling associated costs. Therefore these companies often seek to improve operational performance, increase productivity and promote management of their assets to restrain production costs while satisfying customers’ needs. Maintenance of system components has great impacts on both service quality and also system costs. However, it has been proved that traditional maintenance strategies which have been implemented in electrical companies are inefficient. Thus, Managing maintenance procedures would help companies to reduce their costs... 

Considerable attention has been given in recent years to renewable energy sources due to concerns about dwindling fuel reserves and the potential impact of conventional energy systems on the environment. Wind power is one form of renewable energy resources and also considered as Dispersed Generation (DG). Widespread utilization of wind power imposes many effects on planning and operation of power system. In other side, reliability evaluation and enhancement is an important factor in modern power system planning and operation. So, reliability assessment of wind turbines is of great importance and will receive more attention in the future according to increase of WT utilization. The... 

This thesis represents a comprehensive view of electric vehicles from the macroeconomic policy in the energy sector perspective. In fact, in this thesis all the efficient factors in the presence of electric vehicles in the transport sector have been completely proceed. Environmental, economic, social and political factors, power grids and infrastructure are considered as the impressive factors. In order to check all factors comprehensively, Systems thinking based on dynamic system method is used. The causal relationships between all the variables which are involved in the presence of electric vehicles and related models to this thesis are simulated in VENSIM software. To investigate this... 

Available Transmission Capability (ATC) is a measure of remaining capability in the transmission system for future use which is calculated and posted by Independent System Operator (ISO) considering various certain and uncertain power system parameters. ATC can be affected considerably by application of flexible AC transmission system (FACTS) controller among them Unified Power Flow Controller (UPFC) is the most recent one applied in power systems. This thesis is aimed to study the probabilistic ATC assessment incorporating UPFC. It first proposes a probabilistic ATC calculation method which is capable of considering various certain and uncertain parameters of ATC calculation in the... 

Smart consumers have a major role in the development of the smart grid. On the other hand, increasing need for more flexibility in DGs highlights the consumer’s role. This is possible with the development of smart appliance and appropriate communications infrastructure to active consumers. Today, with the development of smart grids, it is possible to control different parts of home energy systems and manage energy consumption. In this project a comprehensive model has been developed to optimize energy consumption in smart home. In the next phase of the thesis, due to the random nature of solar energy and electric vehicles, stochastic model of smart home energy system is discussed. At this... 

Energy supplement for various demands, including industrial demands, has been human being's challenge over years therefore infrastructures have been developed to generate and transmit energy, gradually. These infrastructures are planned and operated mostly individually so they have less efficiency. Energy hub is a concept that considers energy supplement infrastructures and technologies together. Energy storages play a key role in energy hub. This research intends to provide a framework for industrial load supplement using energy hub concept emphasizing on energy storage role, developing energy supplement optimal size and operation methods. Regarding this method, after introducing main... 

Increasing demand, rising energy costs, and environmental concerns are some of the main challenges faced by the energy industry in upcoming years. With such a diverse set of issues, it is important to take a holistic approach to addressing these concerns and therefore transitioning to a smarter grid. Demand response (DR) has recently been introduced as a promising solution to these issues in the smart grid era. Since residential demand is a significant portion of the total system load, residential customers play critical roles in a proper implementation of DR programs. The main obstacle in broad implementation of residential DR is the low participation of customers in these programs. Lack of... 

Increasing need to electrical energy, gradual diminishing of fossil fuel resources and environmental pollution due to continuous exploitation of them, have lead to inevitable change of energy sources in power generation. Due to random nature of wind speed, the power output of a wind farm is varied and as a result, it does not have a proper control capability. If the wind power has a major role in system generation, the system could not respond to the fluctuations appropriately. With the increasing penetration of wind power, it affects different aspects of power system such as power quality, system stability, and system reliability. Utilizing energy storage systems (ESS) is a solution to... 

This paper proposes a novel real-time pricing tariff design aiming at reducing the operation cost of distribution system. A customer base-line load (CBL) is established for each participant. It let the customer to have less exposure with RTP volatile prices.The tariff charges the consumption above the CBL an hourly varying price. It credits the consumption below the CBL another hourly varying price.The proposed tariff provides the participant with more incentive and discount prices to encourage it to consume more efficient. The optimal prices are determined and announced a day in advance but can change in the next day with a short notice.The response of customers to the tariff prices is... 

Mainly due to the catastrophic effects of electricity service interruptions and their huge damage costs, transmission networks are always designed as meshed networks wherein load points can be served through alternative redundant paths. This redundancy, although it has positive impacts on reliability in general, may worsen the situation during some contingencies. The number of operating constraints imposed by Kirchhoff’s current and voltage laws increases as the number of branches in transmission networks grows. This increment in the number of constraints may force operators to commit costly generation units in normal operation of the network as well as to invoke more unexpected load... 

In the past several decades, with the increasing evolution of electricity markets, maintenance philosophy has gradually changed, and maintenance process plays a crucial role on the profitability and effectiveness of companies. Therefore, this leads managers to use modern strategies that their performance has been proved in various industries and therefore, traditional strategies have lost their effectiveness. Reliability-Centered Maintenance (RCM) is one of the most successful strategies wherein the maintenance process of system components is linked to improvements in the system reliability and profit of companies. RCM has not been thoroughly furnished in generation system yet. This thesis... 

The current restructuring trend in power industry emplaces the owners and managers under a great pressure to not only reduce the associated investment costs, but also reasonably cut the operation and maintenance expenses as much as possible, while keeping both the power quality and reliability requirements met. Reliability-Centered Maintenance (RCM) has been proved to be in response to this dilemma in power systems since it has been yet successfully applied in various engineering contexts worldwide. This process is more challenging when it comes to the power transmission systems because of its bulkiness and complex structure. On the other hand, market involvement and its intricate behavior... 

Current trend of energy consumption and aging infrastructure of electricity grids mandates high amounts of investment in transmission and distribution networks. On the other hand, with increased awareness about environmental issues, share of renewable energy resources in power generation portfolio has risen in recent years. Microgrids, as one of the most promising solutions to tackle these issues, are able to accommodate high penetration levels of renewable energy sources and distributed generation in distribution systems. However, microgrids sizes are limited due to some operational considerations and as a result, efficient management of distribution systems with high penetration of... 

The main concern of power system planners and operators is to serve electric energy services economically and in an acceptable reliability level. Nowadays, in developing integrated large-scale power networks, reliability evaluation becomes a very tough and time-consuming process. The complexity of this assessment is mainly because of the large number of components, their possible operating states, different faults that can happen, and environmental and other affecting parameters. In power systems, in order to address the complexity, reliability evaluation can be conducted in three different levels. The most complicated study among these three levels is HLII that is so-called composite... 

Virtual power plant (VPP) aggregates the capacity of many diverse distributed energy resources (DERs); it creates a single operating profile from a composite of the parameters characterizing each DER and can incorporate the impact of the network on aggregated DER output. In modern power systems, technical virtual power plants (TVPPs) play an important role enabling presence of DERs in electricity markets. This thesis addresses the optimal bidding strategy problem of a TVPP that participates in the day-ahead (DA) electricity market. TVPP schedules its energy resources in a manner that maximize its profit in DA market. Hence, the optimal schedule of its resources is achieved. In a proposed...