Sharif Digital Repository

One of the most essential part of power system are transmission lines. Transmission of power from production centers to consumption centers is duty of these lines. Any disturbance in this duty make great losses to producers and consumers. One of the most disturbance in transmission lines are short circuits that occurred because of various causes. Most faults on transmission lines occurred in stormy weather that make more troubles for fault search. So we need a tool that can find location of fault precisely and quickly. This tool named fault locator. There are many algorithms for fault location and detection on power system transmission lines. These algorithms usually are dependent on very... 

State estimation is a process in which values of unknown system state variables is obtained by considering measurements in such a system. State estimators’ output data are applied in control centers of power systems. Nowadays, using of phasor measurement unit (PMU) in WAMS (Wide Area Measurement Systems) and SCADA have significantly extended. PMUs increase the accuracy proportion compared with traditional measurement units, improve the power networks observability as well as detect and correct bad data. Since the possibility of removing the traditional measurement devices and replacing them with full PMU ones does not exist in the near future it is mandatory to find out an efficient and... 

In this thesis, a reduced model of a distributed one-dimensional Solid Oxide Fuel Cell (SOFC) system is presented. Consequently the reduced model is used to estimate the states of the exact model. The reduced model is derived using the exact solution of the distributed model and implementing the Karhunen-Loève-Galerkin procedure. To achieve an exact solution of the distributed model, method of lines is used. In the method of lines, accuracy of the solution depends on the number of grid points. To increase the accuracy, the number of grid points should be increased which will lead to a high order dynamic model. Such a model is not suitable for state estimation, optimization or control... 

Estimating 3D pose of the human body in videos has many potential applications in motion analysis, surveillance and human computer interfaces. In the last decade using more than one camera causes more accurate pose estimation. Most of the previous works use calibrated and fixed cameras but in action this is not a realistic assumption and using some arbitrary moving cameras is more likely. We introduce a novel method for this purpose. Our approach does not require specifying locations and directions of the cameras. The method uses a database of 3D poses for different human activities. This database includes body silhouettes from multiple viewpoints. To estimate the 3D body pose, silhouettes... 

The restructured power system and smart grid requires an advanced communication infrastructure. Application of such communication infrastructure brings numerous privileges to power generation industry, on the other hand introduces challenges to this industry, namely cyber attacks. Recently, cyber attack in electric markets aiming economic interests have been attractive to many electric industry researchers and planners. In electric market cyber attack, by means of influence in data transmission equipment like SCADA, the attacker manipulates the transferring data. This manipulation is conducted in a targeted behavior so as to make the network operator get wrong estimation of actual LMPs in... 

During past decade, human pose estimation has become a very important topic in computer vision with many applications; such as robotic, human computer interaction, and analyzing sport videos. Pose estimation is the process of estimating the configuration of the body joints from one or more images. Pose estimation in 2D space has been performed by processing of the images of a single camera. Recently, the multi-view methods have been emerged to estimate 3D human pose.The purpose of this thesis is 3D human pose estimation from multi-view images, captured in football matches. Pictorial structure is an efficient method in 2D human pose estimation. The 3D extension of this method is studied in... 

In thisstudy, a three-dimensional modelbased onpartial differential equations (PDEs) was used foraplanarsolid oxidefuel cellunit. These PDEs were evaluatedregardingthe equations ofconservation involvingelectric, ionic charge, mass,energy andmomentum equilibriums.To investigate the behavior and strength of the presented model, thestatic and dynamic analyses were considered. The trend of the system against thechanges incurrent density, flow rateand fuelflow ratewere investigated.The PDE of the real model evaluated using the finite element method inCOMSOLsoftware and The PDE of the EstimatorisimplementedinMATLABenvironment by orthogonalcollocation method.Kalman Nonlinearobserverto estimate... 

The level of current and voltage harmonics in power networks has been increased due to the widespread use of power electronic equipment. This increase may, in turn, result in damage to power system equipment in addition to extra power losses in the network. In order to assess the level of harmonics, it is required to monitor power networks using power quality analyzers. However, due to the high costs, only limited number of measurements can be used in practice. The task of harmonic state estimation is to identify the location and magnitude of harmonic sources and to estimate the harmonic voltage and current by partial measurements. Due to the high price of measurement instruments and... 

The estimation of attitude and deformation of a flexible satellite using magnetometer and sun sensor data are studied in this thesis. To this end, the dynamical differential equations of the flexible satellite have been derived using Lagrange’s equation. These equations of motion are then utilized for the purpose of simulation and verification. After introducing the measurements equations, the observability of the satellite with flexible panels has been evaluated. Afterward, the attitude of the satellite body and deformation of the flexible panels have been estimated by EKF (Extended Kalman Filter) as well as UKF (Unscented Kalman Filter). The results show that the estimations using UKF are... 

In Energy Management Systems, data analysis is done based on the information gathered from the electricity utility. The closer the information is to its real value, the better the data analysis in EMS becomes. Hence, improving the accuracy of the collected information leads to an improvement in data analysis in EMS. The information collected from the network consists of the measured values of voltage phasor at each bus, the generation or load power at each bus, and the power flow in branches. Since the total number of sensors are usually less than the total network’s parameters, it is not possible to precisely determine the values of Network’s parameters, and only an estimation of them can... 

In this work, a non-isothermal model of natural gas in pipelines including mass, momentum and energy balance equations are used as model equations for modeling and state estimation in gas pipeline systems. An algorithm is proposed to handle the discontinuities that appear in the dynamic model of a GTN. The states of GTN are estimated using the continuous/discrete form of the extended Kalman filter for two benchmarks and some heuristic rules for sensor placement in a GTN are concluded. Also, a framework for distributed and decentralized state estimation in high-pressure and long-distance gas transmission networks (GTNs) is proposed. Some heuristic rules are suggested for system decomposition... 

Nonlinear nature of polymerization reactors has always attracted great attentions in various scientific areas such as modeling, simulation, dynamical behavior investigation and control engineering as well. Free radical polymerization in continuous reactors, whether in terms of design and startup or in terms of economical concerns, has numerous fans in industrial aspects. In the following thesis, the dynamical behavior of continuous stirred tank reactor of Vinyl Acetate free radical polymerization is examined in an industrial scale. A control system with optimum performance is designed for this CSTR as well. According to the common behavior of this type of reactor, it may demonstrate... 

In this thesis an algorithm has been implemented for automatic landing of a quadrotor under the ground effect. In this regard the six degrees of freedom equations of motion using the Newton-Euler method has been designed. Then, the ground effect has been modeled by inspiring from the similar available models in the literature. The proposed models and proportional-integral-derivative attitude control loops have been simulated in MATLAB/Simulink environment. Also, two control strategies, a classical proportional-integral-derivative controller and a sliding mode controller have been utilized for height control loop.Since sliding mode controller requires all state variables to generate control... 

Although voltage control and stability issues are not new to the electricity industry, but nowadays, in most modern power systems, special attention has been paid to this issue. Once, only weak systems with long lines were involved in voltage instability, while today due to heavy loading, voltage stability is a serious concern even in developed networks. Over tim, with increasing demand for electricity and emergence of electricity market and economic constraints, power systems are more exposed to voltage instability and even voltage collapse. Therefore, reliable operation of the system in such circumstances requires evaluating voltage stability of the network at both stages of planning and... 

Nowadays, power systems are facing significant changes in traditional network operation and planning approaches with the introduction of distributed generation energy sources and increasing concerns about environmental issues. On the other hand, the Distribution Management System (DMS) in the current situation with low levels of observability and automation, controls and monitors the distribution network, which will not meet the challenges of the Active Distribution Network (ADN). For this purpose, in the first part of this dissertation, considering that the supply of network loads is important from the operator and distribution network management point of view and the voltage range and... 

In recent years, due to the increase in distributed generation, the use of renewable energy sources and the emergence of restructuring and energy markets, traditional distribution networks transform to complex and active distribution networks. These issues, along with requirements such as increasing power quality and reliability, have increased the need to provide active distribution management systems and the use of effective network monitoring, control and protection systems. Due to the complexity and expanse of distribution networks, as well as the development of the use of metering elements and remotely controllable elements, one of the important issues in these systems is the... 

The aim of the present thesis is to develop a novel heuristic filter by utilizing Firefly Optimization Algorithm for state estimation of nonlinear, non-Gaussian systems. The proposed filter formulates the estimation problem as a dynamic, stochastic one. The swarm intelligence of the fireflies enables the filter to find and track the best estimation. To estimate the states of a system, the model of the system is required. Hence, an 8-DoF quadrotor with slung payload system, as a case study, is modeled by the tensor method. In this case, as a highly nonlinear system, in order not to rely on extra sensors for monitoring swing-angle, the estimation of payload states is needed. In this regard,... 

In the early days of implementing state estimation in power systems, only the steady-state and quasi-steady-state models of the system were considered for formulating the state estimation problem, accordingly called, Static State Estimation (SSE). However, after a few decades, with the growing diversity of power system components and complexity of its dynamic phenomena, uncertainty in the power system has dramatically increased. Consequently, the need for situational awareness of the dynamic states of the system (such as rotor angle and speed of the generators) is felt more than ever. In addition, occurrence of the catastrophic blackouts in the world owing to deficiency in dynamic monitoring... 

The purpose of this study is to identify the False Data Injection (FDI) attack and reconstruct the incorrect data created by FDI in the power system using machine learning algorithms. Unlike conventional power grids, the smart grids due to the increase of smart devices and communication networks to transfer power grid information from one point to another and the need to control and monitor the power grid is an electrical network that is integrated with a communication network (cyber-physical system). A communication network that transmits data between the control center and smart meters increases the threat of cyber-attacks in the power grid. In this study, the aim is to investigate the FDI...