Sharif Digital Repository

Data traffic in communication network has increased steadily in recent years. Service requirements have also changed to become more complex. Moreover decrease in relative prices of computation and storage against communication encourages using more caching in these networks . Meanwhile increased use of encryption in internet has forced service providers who were willing to enter content distribution market to cooperate with content providers. But the cooperation is discouraged by willingness of both parties to hide their internal information. There are solutions proposed for interaction and information exchange between ISPs and CPs which are based on game theory. However, these solutions... 

One of the challenges which increasing penetration of renewable energy sources with variable generation brings is the need for more flexibility in the power system. A promising way to overcome the challenge is to have local sources of the flexibility in distribution level. To this end, we present a new model for multi-stage distribution system expansion planning which jointly considers expanding the network assets and increasing the flexibility at local level by installing conventional dispatchable distributed generator units and energy storage systems. Demand response is also considered as another source of the flexibility which can be utilized by the system operator. Since deviating from... 

Expansion planning of distribution network assets is of importance to reliably supply the growing demand. Growing penetration of distributed energy resources (DERs) including renewable based distributed generators (DGs), conventional DGs, energy storage systems, and demand response (DR) resources in the network as well as their operational advantages make it necessary to address the investment planning of these resources in addition to the network assets. In order to effectively utilize the DERs and to solve the challenges arisen by their increasing penetration, active distribution networks (ADNs) are introduced which offer active network management capability. Passing through traditional... 

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... 

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... 

The Technology scaling and reduction of the size of transistors has led to an increase in the switching speed and, as a result, to an increase in the clock frequency.But in recent years, the continuation of this process of increasing the clock frequency has been almost stopped considering the considerations of power consumption. Previous research has shown that approximately 30-50% of the dynamic power consumed by the microprocessor is wasted in the clock distribution network.Therefore, the design of clock distribution networks is a big challenge for future microprocessors due to the trend of Technology scaling and process variation. In this thesis, we used the emerging technology of... 

The purpose of this study is to investigate the resilience of the urban water supply network against earthquakes, A hydraulic analysis of the water supply network was implemented in Rtx software to study the effective parameters in the resilience of the network. Rtx software is a tool for assessing the reliability and resilience of communities and infrastructure to natural hazards by taking into account related uncertainties. The water supply network, like other networks, is affected by earthquakes. The seismic damage varies depending on the vulnerability of the network, the intensity of the earthquake, the focal depth, and the distance from the epicenter. Thus, it reduces the ability of the... 

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 purpose of the current study is developing an evaluation model for the electrical grid. Resilience is an approach toward risk management against disorders and protecting the system during critical conditions. The importance of resilience assessment, especially in crucial infrastructures, has always been at the center of attention. Nonetheless, previous studies in this field were mostly limited to micro-scales, meaning that only a limited part of the system was evaluated. Therefore, such studies rely on technical data and system details. This issue renders macro-scale assessments challenging. Some of the models, which are based on analytical-statistical methods, examine the systems at... 

Recently, demand for using variant applications in distributed networks has been increased largely. Most of these applications are based on group communication.In distributed group communication, two important factors need to be considered, group construction, and Group Key Management (GKM). The group construction specifies the process of constructing a new group by cooperation between distributed users. As well, GKM ensures re-freshness of the group key after each join/leave operation. Both of these tasks must be done by collaboration between members. This leads to imposing complexity and communication overhead to the system.This thesis proposes efficient methods for group construction and... 

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... 

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... 

The regulation is necessary for the electric distribution networks as a natural monopoly. Regulators have been applied the Performance Based Regulation (PBR) for the control of price. The common model of PBR is price cap. Price cap creates sufficient incentive for cost efficiency. However, it decreases the service quality in distribution systems. The aim of this thesis is to design a comprehensive model for improvement of service reliability in the presence of PBR. An incentive model is developed using reward-penalty theory and yardstick theory. Reward-penalty theory is a financial approach that rewards the utility with good reliability and penalizes the utility with poor reliability. The... 

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... 

Implementation of telecommunication-based distribution automation is possible in both centralized and decentralized manners. Although centralized automation is more pervasive than decentralized automation, benefits of decentralized automation systems, like improving reliability and speeding up the fault management process, encourage distribution companies to implement these systems. However, high cost of decentralized automation can be a deterrent to most distribution companies. Therefore, economic planning and creating economic justifications for decentralized distribution automation are necessary for the development of these systems. In this dissertation, economic analysis and planning of... 

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... 

Issues related to the environmental pollution, greenhouse gas emissions, as well as the limited supply of fossil fuels and their rising prices have led to the deployment of distributed energy technologies in power systems. With the increasing penetration of distributed energy sources in distribution systems, smart grids, and in particular, microgrids have emerged as a suitable and widely accepted solution for controlling and utilizing these resources. Microgrids can enhance energy efficiency in a sustainable power grid as well as the reliability of the distribution system, through supporting high penetration of renewable energy sources and providing island performance.In view of growing... 

Water is crucial to human being. We use water for a wide variety of uses daily. However, leakage has caused substantial water loss to our precious processed water. The major contributor to non-revenue water in Iran is pipeline leakages. The water industry in the nation has invested in equipment to detect and localize leaks in water distribution systems. One of the equipment mentioned is acoustic-based. The principle of acoustic is that whenever a leak is present in a pipeline, noise is generated and will travel along the pipeline. The acoustic leak detection method is then derived by calculating the distance traveled by this noise generated by the leak. Different equipment based on acoustic... 

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... 

The major goal of the power industry is to serve the demand of electricity consumers as reliable as possible but at an affordable cost. Towards the goal, however, the industry faces substantial barriers such as aging infrastructures, growing demand, and limited budgets for reinforcements. A great portion of infrastructures which were built decades ago need to be retired. The growing demand needs system reinforcement and expansion. These, in turn, require considerable amounts of investment which is in contradiction with highly limited budget of the power industry. This critical situation forces the industry to utilize the existing system more efficiently and wisely. To this end, the concept...