Sharif Digital Repository

Nowadays, improvement in operational condition of distribution networks considering daily growth in electrical energy usage with financial limits appears as a huge challenge for network operators. Under these kind of circumstances, operators need to have efficient and inexpensive plans more than ever. Considering high share of power losses in overall pro-duced power, utilities always tried to minimize losses in Iran and other points of world. In addition, numerous equipment in distribution networks compared with the transmission level, impose high costs to reliability plans. Therefore, reliability improvement plans have been paid low attention by distribution network operators. This lower... 

Back then and still now natural calamities have been a serious threat for energy systems. On that front, this thesis constitutes a three-stage mixed integer linear programming (MILP) model to enhance the resilience of power distribution systems to deal with disas-trous events. The proposed model involves in pre-, mid-, and post-event stages. In this con-text, to increase the preparedness of the power distribution system, system operator recon-figures the system by taking benefit of remote-control switches (RCSs), manual switches (MSs), and distributed generations (DGs) before the natural calamity hits. The proposed model contemplates the traveling time of crew teams to the MS sites in order... 

Prompt service restoration following faults has always been a concern to power distribution utilities. In this regard, optimal human resource allocation in post-fault service restoration can speed up field remedial actions which count for significant portion of service interruption duration. This thesis develops a fault management navigator that dispatches crews for field actions in a sequential service restoration until the network is restored to the normal state. The developed navigator effectively coordinates manual and remote switching actions as well as repair actions in the hope of achieving minimum service interruption cost. It tackles a real-time problem, periodically updating the... 

With the rapid proliferation of residential rooftop photovoltaic (PV) systems, current and voltage unbalance issues have become a matter of great concern in low voltage (LV) distribution feeders. This, however, necessitates identification of the hosting phase of the connected single-phase customers and PV panels. Both of the challenges have been addressed in this thesis. In the first place, this thesis proposes a mixed integer linear programming (MILP) model for phase identification problem. The model considers potential error in the input data provided by smart meters. To mitigate negative impacts of the error, the data associated with several consecutive time intervals are taken into... 

By intertwining community daily life to electricity, high reliability and quality, safe, and low-cost services become among common expectations of electric energy customers. The substantial sources of fault events, however, lead to unexpected service interruptions. The exhaustion of existing devices, radial structure of current distribution networks, and lack of sufficient control and monitoring systems even worsen the situation. Therefore, investing in distribution systems in order to improve the service reliability and quality has been deemed as a proper strategy for electricity planners and operators. Various approaches have been proposed to achieve this aim. Among them, implementing... 

Thesedays, the electric power industry faces not only increasing electrical demand, but also improving the performance of electrical energy systems. In order to provide these requirements, the concept of smart grid is presented by academic researchers and industry experts. In different parts of a smart grid, the application of various technologies for easy monitoring and control of the system improves its performance. On demand side, making smart is the equivalent of smart consumption management to reduce energy consumption or cost. Considering the high contribution of heating/cooling loads to the energy consumption basket, and the high flexibility of these loads due to thermal inertia, the... 

The worldwide increase in greenhouse gases is one of the most important human concerns today, and reducing emissions is on the agenda of politicians and the international community. Globally, the transportation fleet is one of the major sources of environmental pollutants due to the use of fossil fuels, and replacing this fleet with electric vehicles will play an important role in reducing the emission of environmental pollutants. These environmental concerns and the advancement of technologies used in electric vehicles in recent years have led to a relative increase in the presence of electric vehicles in the transportation network. The acceptance of these cars, on the one hand,... 

The development of smart meters enables gathering and analysis of a large amount of data about electrical energy consumption in electric power distribution systems. This data and the obtained behavioral patterns of customers have a wide variety of applications. To name a few, classification of customers based on their consumption patterns, damaged smart meter identification, non-technical loss identification and measuring participation rate of customers in demand response programs are among the applications. So far, many studies have been done for consumption pattern identification. However, abnormality detection in electric energy consumption has captured growing attention due to the... 

In recent years, due to improved quality and lower solar panel prices, the use of this renewable energy source in the world has increased dramatically. The proliferation and expansion of the solar panels in the distribution systems, at the time when the solar energy production reaches its maximum value, increases the voltage at the end of the low voltage feeder. This issue cause limitations on the installed photovoltaic capacity in the system. So far, several methods have been proposed to overcome this problem and increase the installed photovoltaic capacity. Demand response is one of the proposed methods. This thesis, with upgrading one of the proposed methods provides a model to make... 

This thesis proposes a probabilistic modeling framework for networked infrastructure systems in community resilience analysis. In particular, the framework is presented for the electric power infrastructure. Models are proposed at two levels of refinement. The basic model only determines the connectivity of different elements in the network, whereas the refined model also quantifies the amount of the power transmitted through the network elements. In a community resilience analysis, the proposed basic model provides a rather simple tool to determine those buildings and infrastructure systems that suffer from power outage when the supplying power station loses connectivity with the network.... 

High voltage power supplies (HVPS) are widely used to supply the vacuum tubes. The function of this power supply is disturbed by some internal and external faults. One of the external faults is the arc fault in the tube. The amount of delivered energy from the HVPS to the tube is an important issue during the arc fault in the tube. The conventional protection mechanism consists of a shunt crowbar device which divert the fault current from the tube arc. The crowbar circuit is usually built with thyristor in most cases. This type of crowbar cannot be turned off simply by protection command. It is a drawback since if the fault is transient such as arc in the load or false fault detection is... 

In recent decades, the trend towards renewable energy sources has increased dramatically. Rising fossil fuel prices and concerns about the effects of greenhouse gases and carbon dioxide emissions have drawn the attention of many energy experts to the use of renewable energy sources such as wind farms as an alternative to fossil fuel energy sources. Therefore, the issue of reliability related to these sources and whether such units can be considered as a source of generation has gained more importance. Due to the random nature of wind power, the share of these power plants in providing system adequacy is less than their nominal value. Therefore, determining the capacity value of wind power... 

Electric energy distribution system (DS) reliability has a great impact on the quality of service provided to customers. On the other hand, improving the reliability performance in a DS is an expensive task. So, determining an efficient and economical target for the reliability of DSs is imperative. This thesis aims to determine efficient and economical reliability targets for reliability indices of DS based on data envelopment analysis (DEA) considering distribution feeders as the decision-making units (DMUs). For this sake, using the fuzzy c-mean (FCM) method, feeders are clustered and the membership degrees are determined so that the target associated with each feeder gets greater impact... 

Nowadays, electricity has a substantial impact on various aspects of peoples’ life, which has captured the attention of electricity planners and operators. However, despite the expectation of customers to have access to an uninterrupted electricity, multitude of technical and economical challenges prevent to achieve fully reliable power supply. Due to especial structure of distribution systems and limited investment budgets, distribution systems play a critical role in delivering electricity to the customers. According to past statistical information, up to 80 percent of electricity outage originates from failure of distribution equipment or the matters relevant to distribution level....