Sharif Digital Repository

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... 

Implementing distribution automation system (DAS) in distribution networks needs a huge investment which usually cannot be funded entirely in a short period of time. So distribution companies (DISCOs) should develop long term plans to equip their network with automation technologies as far as economically justifiable. Similarly, DISCOs have network capacity expansion (NCX) plans which specify the scheme of construction of feeders and substations. Since considering DAS may lead to more efficient NCX plans, the planner should revise the NCX plan through the DAS planning. On the other hand, for DAS planning it is necessary to consider a NCX plan as a platform to determine the time and location... 

Distribution power systems are undergoing a fundamental transition with the introduction of microgrids (MGs) and proliferation of renewable energy sources inspired mainly by privacy and environmental concerns. In this regard, energy management methods employed by utilities should take into account the intermittent nature of RESs power production while coping with the independent operation of MGs. Transactive energy (TE) is an emerging concept which utilizes economic-based mechanisms to facilitate the dynamic and decentralized management of active agents of the system. However, the energy transactions between transactive agents could have adverse impacts on the technical aspect of the system... 

According to uncertainty of retailer's customers electricity load and energy price in day-ahead and real-time markets, different scenarios are faced to an electricity retailer. As a result, due to possibility of different scenarios accurance, profit and financial loss of retailer has uncertainty and significant financial risk is imposed to retailer. Electricity retailers for earning the expected profit, reduction ofpossibility of scenarios with little profit (or much loss) and reduction of their risks, use different sources. bilateral contracts, like forward and call option,local wind turbines, distributed generaion, demand response, like load shift and curtailment can be named. This... 

In recent years, the development of demand response programs with the aim of activating the demand side in order to achieve a wide range of economic and technical benefits in the development of the power system structure has been considered. With the implementation of incentive-based demand response plans, customers receive financial rewards based on changing their load pattern in the favor of electricity companies. However, mid-term and long-term planning to take advantage of this potential requires accurate estimation of the demand response potential in the power system. Also, the value of the baseline load curve of the customers (an estimate of the energy consumption of the customers if... 

A high percentage of power grid faults occur in the distribution sector, which causes customers to experience power outages. In order to maintain a good reputation with customers and maximize their satisfaction, improving the reliability of the services provided in the electricity distribution network and minimizing related costs have always been one of the most important challenges for electricity network managers. Therefore, managers and legislators of the power network are always looking for a way to maintain the reliability level of the power distribution network and also to improve it. So far, many researchers have focused on setting goals with the help of average performance methods... 

Planning of distribution networks is usually accomplished using a cost-based conventional model that minimizes the total cost of construction and reinforcement of substations and feeders. The resulted expansion plan designed by this cost-based model is not necessarily the best choice for an electrical distribution company in the nowadays deregulated structure. This happening is mainly due to the fact that the utility seeks to maximize its profit in this competitive environment. On the other hand, this model does not consider the upcoming new challenges ahead of distribution systems, such as smart grid and automation. This thesis presents a novel profit-based model for multi-stage... 

The change in distribution and consumption of electrical energy has increased attention to smart grid. The smart grid is expected to enhance efficiency and reliability of power systems. Along with the important features, cyber security emerges to be a critical issue because electronic devices are inter-connected via communication and computer networks throughout power facilities. In recent years, cybersecurity of intelligent electronic devices (IEDs) in the substations has been recognized as a critical issue for the electrical smart grid. These devices provide remote accesses to perform the given control commands. Taking this into account, some concern has arised about cyber threats result... 

Necessity of uninterruptable electricity supply is one of the most fundamental needs nowadays. To achieve this, power system are designed and operated based on adequacy and security metrics which are based on reliability. Despite efficient influence of these metrics in normal condition, they do not have appropriate function while facing natural weather disasters. Since these events are low probability, these event do not affect adequacy metrics incredibly. Additionally, reliability metrics are compute base on intrinsic failure rate of component while each weather disaster causes specific failure rate. Furthermore, number of failures in such events is too many to be handled by N-1 operation... 

The penetration of variable energy resources together with the utilization of price sensitive loads have intensified supply and demand uncertainties in power systems. Accordingly, system operators and market participants are now seeking for new ways of managing risks within the power system. In this thesis, the risk management is studied from the viewpoints of market participants, transactive market operators and wholesale market operators. In this regard, the optimal bidding strategy of a market participant who participate in wholesale or transactive electricity markets is studied in chapter 3. To reach this goal, behaviors of both risk-neutral and risk-averse agents are modeled taking into... 

In spite of the fact that failures in distribution systems constitute a high percentage of customer’s interruptions, they have received less attention than generation and transmission systems at least in the amount of academic and industrial publications in the past decades. However as the business turns its attention to customers from consumers, focuses are moving toward power distribution systems in recent years. Its main problem that makes this high percentage of contribution in customer’s interruption is their widespread applications through all the places that there is a civilization. Contribution of many components in the system leads to high failure rate and because they spread every... 

With increasing demand levels in recent years, transmission congestion is considered as one of the most important power system constraints. This limitation can result in higher operational costs and load curtailment. Furthermore, in power systems with high penetration of wind power, a significant amount of wind curtailment may occur due to congestion of transmission lines. Thus, in order to guarantee a reliable and economic operation of the power system, new transmission lines should be constructed with a rational plan. Very high investment costs are required for building new transmission lines to meet the growing demand. This fact as well as the other associated difficulties emphasize the... 

The design and operation of energy systems infrastructure is typically based on key reliability criteria such as system security and adequacy. Nowaday, with the rise of unexpected events and events such as floods, earthquakes, storms, and other natural phenomena can affect the performance of energy infrastructure. Given the low probability of these events, reliability studies and relevant criteria cannot guarantee that an energy infrastructure can respond well to these events. Investigating the ability of energy infrastructures to deal with these phenomena is divided into resilience studies. To overcome these challenges, this thesis has attempted to detail some of these natural events.... 

Nowadays, with the expansion of restructuring and privatization in power systems, energy markets are growing rapidly, within distribution networks. In order for such markets to be implemented in practice, the technical constraints and issues of the distribution network, which are mainly the power loss and congestion of lines and also the bus voltage violations, must also be considered within the framework provided for them. Hence, this dissertation presents some new structures for Peer-to-peer (P2P) energy markets, in which the technical issues of the distribution network could be considered. Moreover, a model predictive control method is used in the proposed structures of this dissertation... 

Nowadays, moving toward new technologies and smart grids is a successful way to prevail over distribution system challenges. In the presence of smart grids, demand-side management (DSM) is capable to affect the expansion of network resources. An effective DSM tool is demand response (DR). In this thesis, distribution system planning (DSP) considering DR is presented and the effects of DR on DSP are investigated. This thesis proposes direct load control (DLC) DR which is an incentive-based program (IBP) where a utility offers financial incentives to the customers to control their consumption through installing smart meters and switches. The utility deploys the DR program to reduce network... 

Recent widespread blackouts around the world have highlighted the fact that power grids must not only ensure reliability against high-probability, low-impact events (HPLI), but also against low-probability, high-impact events (HILP) such as earthquakes, hurricanes, and hurricanes and resist against unnatural events such as cyber attacks. On the other hand, transformation of traditional electricity distribution systems into smart networks that have the ability to automatically perform switching and fault locating can enable utilities to minimize operational costs in case of HILP events occurences. Although the use of distribution automation has been suggested as one of the smart grid...