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Letteratura scientifica selezionata sul tema "Phasor estimation"

Autore: Grafiati

Pubblicato: 4 giugno 2021

Ultima modifica: 7 settembre 2023

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Articoli di riviste sul tema "Phasor estimation"

Zhao, Dongfang, Fuping Wang, Shisong Li, Wei Zhao, Lei Chen, Songling Huang, Shen Wang e Haitao Li. "An Optimization of Least-Square Harmonic Phasor Estimators in Presence of Multi-Interference and Harmonic Frequency Variance". Energies 16, n. 8 (12 aprile 2023): 3397. http://dx.doi.org/10.3390/en16083397.

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The wide application of power electronic devices brings an increasing amount of undesired harmonic and interharmonic tones, and accurate harmonic phasor estimation under a complex signal input is an important task for smart grid applications. In this paper, an optimization of least-square dynamic harmonic phasor estimators, considering multi-interference and harmonic frequency variance, is proposed. A comprehensive error index (CEI) composed of the fundamental-leakage-led harmonic amplitude estimation error, harmonic mutual interference, out-of-band interference, and harmonic frequency deviation is employed. The largest CEI part of least-square algorithms using three different signal decomposition models is analyzed for the first time, and variables to reduce this error component are then introduced using singular value decomposition. With the CEI and defined variables, a minimum-error estimation of harmonic phasors under various interference and harmonic frequency change is discussed. Numerical tests are performed, and the test results show that after the proposed optimization is applied to least-square algorithms, the harmonic phasor estimation errors are considerably reduced, especially for low-order harmonics. We also show the possibility of choosing desired optimal phasor filter design by balancing the measurement accuracy and data latency. For example, when the window length is set to three nominal cycles, the proposed optimization can yield both good accuracy and fast measurement speed for estimating harmonic phasors under multi-interference and harmonic frequency variance.

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Chukkaluru, Sai Lakshmi, e Shaik Affijulla. "Review of Discrete Fourier Transform During Dynamic Phasor Estimation and the Design of Synchrophasor Units". ECTI Transactions on Electrical Engineering, Electronics, and Communications 21, n. 1 (28 febbraio 2023): 248548. http://dx.doi.org/10.37936/ecti-eec.2023211.248548.

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In a large and complex interconnected power system, the measurement of synchronized bus voltage and line current plays a vital role in the monitoring and precise control of various sophisticated electrical equipment for secure and reliable operation. Phasor measurement units (PMUs) are incorporated into a wide area of the power system to extract the different signals of synchronized phasors. In this paper, the capacity of the PMU phasor estimation algorithm is explored based on discrete Fourier transform (DFT) under different sampling frequency rates during various dynamic scenarios in accordance with the IEEE C37.118.1a-2014 standard. Furthermore, the performance of the DFT algorithm varies according to the phase angle and dynamic parameters such as frequency, frequency ramp rates, modulation frequency, harmonic levels, step change, decaying dc, and noise levels. The simulation results reveal that accuracy of the phasor estimation algorithm based on DFT can be achieved at high sampling frequency rates. Furthermore, the results of DFT-based phasor estimation are compared with Shank’s estimation method (SEM) and the least-squares estimation method (LEM). The presented method is best suited to PMU algorithms development based on DFT for better visualization of the smart electric grid.

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Guo, Yufu, Hang Xu e Aobing Chi. "Broadband Dynamic Phasor Measurement Method for Harmonic Detection". Electronics 11, n. 11 (24 maggio 2022): 1667. http://dx.doi.org/10.3390/electronics11111667.

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A large number of nonlinear loads and distributed energy sources are connected to the power system, leading to the generation of broadband dynamic signals including inter-harmonics and decaying DC (DDC) components. This causes deterioration of power quality and errors during power measurement. Therefore, effective phasor estimation methods are needed for accurate monitoring and effective analysis of harmonics and interharmonic phasors. For this purpose, an algorithm is proposed in this paper that is implemented in two parts. The first part is based on the least square method in order to obtain accurate DDC component. In the second part, a Taylor–Fourier model of broadband dynamic harmonic phasor is established. The regularization optimization problem of the sparse acquisition model is solved by harmonic vector estimation method. Finally, the piecewise Split-Bregman Iterative (SBI) framework is used to obtain the estimated value of the harmonic phasor measurement and to realize the reconstruction of the original signal. Through simulation and performance test, the proposed algorithm significantly improves the accuracy of the phasor measurement and estimation, and can provide a reliable theoretical basis for the PMU measurement.

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Giotopoulos, Vasilis, e Georgios Korres. "Implementation of Phasor Measurement Unit Based on Phase-Locked Loop Techniques: A Comprehensive Review". Energies 16, n. 14 (18 luglio 2023): 5465. http://dx.doi.org/10.3390/en16145465.

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Abstract (sommario):

The dynamic monitoring, control, and protection of modern power systems in real time require time-stamped electrical measurements to accurately estimate the bus voltage phasors using the state estimation function under normal and abnormal conditions. These measurements can be acquired by time-synchronized devices, known as phasor measurement units (PMUs). PMUs can measure bus voltage and branch current phasors of a three-phase network, as well as the frequency and the rate of change of frequency (ROCOF), with high speed, accuracy and time stamping provided by global positioning system (GPS) at the coordinated universal time (UTC). Various phasor estimation algorithms have been proposed in the literature, while most of them are concentrated in the discrete Fourier transform (DFT) algorithm, where an integer number of samples multiple of the nominal frequency is required for the computations. In cases where the frequency of the power grid deviates from its nominal value, the raw application of the DFT approach can lead to large errors during phasor estimation. Another approach of the phasor estimation is based on the phase-locked loop (PLL) techniques, widely used in grid tie inverters. PLL techniques can track dynamically (continuous time) the estimated frequency to the time-variant frequency of the power grid. A brief introduction to the basic concepts of the synchrophasor definition is provided, while the main DFT methods for synchrophasor estimation according to recent literature are mentioned. PLL-based PMU techniques are reviewed for both steady-state and dynamic conditions according to IEEE standards. In conclusion, the performance of PLL-based PMU algorithms presented in this literature review is discussed.

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Parthasarathy, Hari Krishna Achuthan, Madhusudan Saranathan, Adhitya Ravi, M. C. Lavanya e V. Rajini. "Comparative Analysis of Phasor Estimation Techniques for PMU Applications". Journal of Physics: Conference Series 2325, n. 1 (1 agosto 2022): 012010. http://dx.doi.org/10.1088/1742-6596/2325/1/012010.

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Abstract Phasor Measurement Units (PMU) are valuable sources of data which increase the visibility into several fields of application such as power production, transmission and distribution. With the initial goal of obtaining phasor values at fixed points in the network and syncing it to a standard time frame, the technology has morphed into an all-encompassing unit, which has its uses in the field of protection, control and automation. With the application of these units becoming a standard benchmark, the improvement in the current available units is a huge requirement. This study presents a comprehensive analysis of various techniques that is used for the estimation of phasors.

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Liu, Min. "Distribution System State Estimation with Phasor Measurement Units". Applied Mechanics and Materials 668-669 (ottobre 2014): 687–90. http://dx.doi.org/10.4028/www.scientific.net/amm.668-669.687.

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With phasor measurement units (PMU) become available in the distribution system; the estimation accuracy of the distribution system state estimation (DSSE) is expected to be improved. Based on the weighted least square (WLS) approach, this paper proposed a new state estimator which takes into account the PMU measurements including voltage magnitude and phasor angle, and load current magnitude and phasor angle. Simulation results indicate that the estimation accuracy is obvious improve by adding PMU measurements to the DSSE. Furthermore, the estimation accuracy changes with the installation site of PMU, and can be maximized by choosing the installation site appropriately.

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Xiao, Xianyong, Runze Zhou, Xiaoyang Ma e Rui Xu. "Harmonic Phasor Estimation Method Considering Dense Interharmonic Interference". Entropy 25, n. 2 (27 gennaio 2023): 236. http://dx.doi.org/10.3390/e25020236.

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Due to the limitation of frequency resolution and the spectrum leakage caused by signal windowing, the spectrums of harmonic and interharmonic components with close frequencies overlap each other. When the dense interharmonic (DI) components are close to the harmonic spectrum peaks, the harmonic phasor estimation accuracy is seriously reduced. To address this problem, a harmonic phasor estimation method considering DI interference is proposed in this paper. Firstly, based on the spectral characteristics of the dense frequency signal, the phase and amplitude characteristics are used to determine whether DI interference exists in the signal. Secondly, an autoregressive model is established by using the autocorrelation of the signal. Data extrapolation is performed on the basis of the sampling sequence to improve the frequency resolution and eliminate the interharmonic interference. Finally, the estimated values of harmonic phasor, frequency and rate of change of frequency are obtained. The simulation and some experimental results demonstrate that the proposed method can accurately estimate the parameters of harmonic phasors when DIs exist in the signal, and has a certain anti-noise capability and dynamic performance.

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Mejia-Barron, Arturo, David Granados-Lieberman, Jose Razo-Hernandez, Juan Amezquita-Sanchez e Martin Valtierra-Rodriguez. "Harmonic PMU Algorithm Based on Complex Filters and Instantaneous Single-Sideband Modulation". Electronics 8, n. 2 (29 gennaio 2019): 135. http://dx.doi.org/10.3390/electronics8020135.

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Phasor measurement units (PMUs) have become powerful monitoring tools for many applications in smart grids. In order to address the different issues related to harmonics in power systems, the fundamental phasor estimator in a PMU has been extended to the harmonic phasor estimator by several researchers around the world. Yet, the development of harmonic phasor estimators is a challenge because they have to consider time-varying frequencies since the frequency deviation in the harmonic components is proportional to the harmonic order in a dynamic way. In this work, a new algorithm for harmonic phasor estimation using an instantaneous single-sideband (SSB) modulation is presented. Unlike other SSB-based approaches, its implementation in this work is based on concepts of instantaneous phase and instantaneous frequency. In general, the proposed algorithm is divided into two stages. Firstly, the estimation of the fundamental phasor is carried out by means of a complex finite impulse response (FIR) filter which provides the analytic signal used to compute the instantaneous magnitude, phase, and frequency. Secondly, a complex FIR filter bank is proposed for the estimation of the harmonic components, where the instantaneous SSB modulation technique is applied in order to center the harmonic components into specific narrow bands for each complex filter when an off-nominal frequency occurs. The validation of the proposed algorithm is carried out by means of the current standards of phasor measurement units, i.e., Std. C37.118.1-2011 and C37.118.1a-2014, which involve steady-state, dynamic, and time performance tests.

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delaOSerna, J. A. "Phasor Estimation From Phasorlets". IEEE Transactions on Instrumentation and Measurement 54, n. 1 (febbraio 2005): 134–43. http://dx.doi.org/10.1109/tim.2004.838914.

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Chi, Aobing, Chengbi Zeng, Yufu Guo e Hong Miao. "A Bregman-Split-Based Compressive Sensing Method for Dynamic Harmonic Estimation". Entropy 24, n. 7 (17 luglio 2022): 988. http://dx.doi.org/10.3390/e24070988.

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In order to overcome the spectral interference of the conventional Fourier transform in the International Electrotechnical Commission framework, this paper introduces a Bregman-split-based compressive sensing (BSCS) method to estimate the Taylor–Fourier coefficients in a multi-frequency dynamic phasor model. Considering the DDC component estimation, this paper transforms the phasor problem into a compressive sensing model based on the regularity and sparsity of the dynamic harmonic signal distribution. It then derives an optimized hybrid regularization algorithm with the Bregman split method to reconstruct the dynamic phasor estimation. The accuracy of the model was verified by using the cross entropy to measure the distribution differences of values. Composite tests derived from the dynamic phasor test conditions were then used to verify the potentialities of the BSCS method. Simulation results show that the algorithm can alleviate the impact of dynamic signals on phasor estimation and significantly improve the estimation accuracy, which provides a theoretical basis for P-class phasor measurement units (PMUs).

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Più fonti

Tesi sul tema "Phasor estimation"

Jones, Kevin David. "Three-Phase Linear State Estimation with Phasor Measurements". Thesis, Virginia Tech, 2011. http://hdl.handle.net/10919/32119.

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Given the ability of the Phasor Measurement Unit (PMU) to directly measure the system state and the increasing implementation of PMUs across the electric power industry, a natural expansion of state estimation techniques would be one that employed the exclusive use of PMU data. Dominion Virginia Power and the Department of Energy (DOE) are sponsoring a research project which aims to implement a three phase linear tracking state estimator on Dominionâ s 500kV network that would use only PMU measurements to compute the system state. This thesis represents a portion of the work completed during the initial phase of the research project. This includes the initial development and testing of two applications: the three phase linear state estimator and the topology processor. Also presented is a brief history of state estimation and PMUs, traditional state estimation techniques and techniques with mixed phasor data, a development of the linear state estimation algorithms and a discussion of the future work associate with this research project.
Master of Science

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Chen, Jian. "Accurate frequency estimation with phasor angles". Thesis, This resource online, 1994. http://scholar.lib.vt.edu/theses/available/etd-12042009-020203/.

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Chen, Jiaxiong. "Power System State Estimation Using Phasor Measurement Units". UKnowledge, 2013. http://uknowledge.uky.edu/ece_etds/35.

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State estimation is widely used as a tool to evaluate the real time power system prevailing conditions. State estimation algorithms could suffer divergence under stressed system conditions. This dissertation first investigates impacts of variations of load levels and topology errors on the convergence property of the commonly used weighted least square (WLS) state estimator. The influence of topology errors on the condition number of the gain matrix in the state estimator is also analyzed. The minimum singular value of gain matrix is proposed to measure the distance between the operating point and state estimation divergence. To study the impact of the load increment on the convergence property of WLS state estimator, two types of load increment are utilized: one is the load increment of all load buses, and the other is a single load increment. In addition, phasor measurement unit (PMU) measurements are applied in state estimation to verify if they could solve the divergence problem and improve state estimation accuracy. The dissertation investigates the impacts of variations of line power flow increment and topology errors on convergence property of the WLS state estimator. A simple 3-bus system and the IEEE 118-bus system are used as the test cases to verify the common rule. Furthermore, the simulation results show that adding PMU measurements could generally improve the robustness of state estimation. Two new approaches for improving the robustness of the state estimation with PMU measurements are proposed. One is the equality-constrained state estimation with PMU measurements, and the other is Hachtel's matrix state estimation with PMU measurements approach. The dissertation also proposed a new heuristic approach for optimal placement of phasor measurement units (PMUs) in power system for improving state estimation accuracy. In the problem of adding PMU measurements into the estimator, two methods are investigated. Method I is to mix PMU measurements with conventional measurements in the estimator, and method II is to add PMU measurements through a post-processing step. These two methods can achieve very similar state estimation results, but method II is a more time-efficient approach which does not modify the existing state estimation software.

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Zhou, Ming. "Advanced System Monitoring with Phasor Measurements". Diss., Virginia Tech, 2008. http://hdl.handle.net/10919/27813.

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Phasor Measurement Units (PMUs) are widely acknowledged as one of the most promising developments in the field of real-time monitoring of power systems. By aligning the time stamps of voltage and current phasor measurements that are consistent with Coordinated Universal Time (UTC), a coherent picture of the power system state can be achieved through either direct measurements or simple linear calculations. With the growing number of PMUs planned for installation in the near future, both utilities and research institutions are looking for the best solutions to the placement of units as well as to the applications that make the most of phasor measurements. This dissertation explores a method for optimal PMU placement as well as two applications of synchronized phasor measurements in state estimation. The pre-processing PMU placement method prepares the system data for placement optimization and reduces the size of the optimization problem. It is adaptive to most of the optimal placement methods and can save a large amount of computational effort. Depth of un-observability is one of the criteria to allow the most benefit out of a staged placement of the units. PMUs installed in the system provide synchronized phasor measurements that are highly beneficial to power system state estimations. Two related applications are proposed in the dissertation. First, a post-processing inclusion of phasor measurements in state estimators is introduced. This method avoids the revision of the existing estimators and is able to realize similar results as mixing phasor data with traditional SCADA with a linear afterwards step. The second application is a method to calibrate instrument transformers remotely using phasor measurements. Several scans of phasor measurements are used to accomplish estimating system states in conjunction with complex instrument transformer correction factors. Numerical simulation results are provided for evaluation of the calibration performance with respect to the number of scans and load conditions. Conducting theoretical and numerical analysis, the methods and algorithms developed in this dissertation are aimed to strategically place PMUs and to incorporate phasor measurements into state estimators effectively and extensively for better system state monitoring. Simulation results show that the proposed placement method facilitates approaching the exact optimal placement while keep the computational effort low. Simulation also shows that the use of phasor measurement with the proposed instrument transformer correction factors and proposed state estimation enhancement largely improves the quality of state estimations.
Ph. D.

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Khan, Muhammad Ayaz. "State Estimation and Voltage Phasor Measurements in Distribution Networks". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2018.

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Abstract (sommario):

The thesis faces the problem of the use of phasor measurement units (PMU) for the state estimation in distribution networks, and in particular the problem of a suitable phasor estimation in different buses of a distribution network in absence of proper time synchronization with the universal time reference. In particular, an approach recently proposed by Mingotti et al. to obtain an equivalent synchronization, starting from asynchronous measurement has been presented and tested. This method assumes the availability of a distributed measurement system where each remote unit is a power meter. The algorithm implemented in Matlab by Mingotti et al. has been studied and tested by a comparison with the load flow results provided by the Electromagnetic Transient Program (EMTP-RV). The algorithm adopts two different methods for voltage phasor estimation, the first calculate the phasors as a linear combination of measured voltages, the second makes use of the longitudinal equivalent impedances of the network branches. In order to tune the load flow calculation environment, different case studies have been analyzed, and in particular the European Medium Voltage distribution test network and the European Low voltage distribution test network proposed by CIGRE Task Force C6.04.02. During the analysis, for each bus, voltages, currents and phase displacements are calculated and compared with the benchmark results reported in the Cigré brochure. A four-buses network has been considered to test both methods of the above mentioned algorithm. The obtained results are very close to the one provided by EMTP. The accuracy of the algorithm appears to get worse in case of lightly loaded network, a behaviour that is justified by the small phase displacements that the voltages show in these condition. The studied equivalent synchronization procedure can be usefully implemented to achieve a widespread monitoring of a power network at affordable cost.

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Hurtgen, Michaël. "Wide-area state estimation using synchronized phasor measurement units". Doctoral thesis, Universite Libre de Bruxelles, 2011. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209924.

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State estimation is an important tool for power system monitoring and the present study involves integrating phasor measurement units in the state estimation process. Based on measurements taken throughout the network, the role of a state estimator is to estimate the state variables of the power system while checking that these estimates are consistent with the measurement set. In the case of power system state estimation, the state variables are the voltage phasors at each network bus.\\

The classical state estimator currently used is based on SCADA (Supervisory Control and Data Acquisition) measurements. Weaknesses of the SCADA measurement system are the asynchronicity of the measurements, which introduce errors in the state estimation results during dynamic events on the electrical network.\\

Wide-area monitoring systems, consisting of a network of Phasor Measurement Units (PMU) provide synchronized phasor measurements, which give an accurate snapshot of the monitored part of the network at a given time. The objective of this thesis is to integrate PMU measurements in the state estimator. The proposed state estimators use PMU measurements exclusively, or both classical and PMU measurements.\\

State estimation is particularly useful to filter out measurement noise, detect and eliminate bad data. A sensitivity analysis to measurement errors is carried out for a state estimator using only PMU measurements and a classical state estimator. Measurement errors considered are Gaussian noise, systematic errors and asynchronicity errors. Constraints such as zero injection buses are also integrated in the state estimator. Bad data detection and elimination can be done before the state estimation, as in pre-estimation methods, or after, as in post-estimation methods. For pre-estimation methods, consistency tests are used. Another proposed method is validation of classical measurements by PMU measurements. Post-estimation is applied to a measurement set which has asynchronicity errors. Detection of a systematic error on one measurement in the presence of Gaussian noise is also analysed. \\

The state estimation problem can only be solved if the measurements are well distributed over the network and make the network observable. Observability is crucial when trying to solve the state estimation problem. A PMU placement method based on metaheuristics is proposed and compared to an integer programming method. The PMU placement depends on the chosen objective. A given PMU placement can provide full observability or redundancy. The PMU configuration can also take into account the zero injection nodes which further reduce the number of PMUs needed to observe the network. Finally, a method is proposed to determine the order of the PMU placement to gradually extend the observable island. \\

State estimation errors can be caused by erroneous line parameter or bad calibration of the measurement transformers. The problem in both cases is to filter out the measurement noise when estimating the line parameters or calibration coefficients and state variables. The proposed method uses many measurement samples which are all integrated in an augmented state estimator which estimates the voltage phasors and the additional parameters or calibration coefficients.
Doctorat en Sciences de l'ingénieur
info:eu-repo/semantics/nonPublished

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Yang, Xuan. "Distributed state estimation with the measurements of Phasor Measurement Units". Thesis, University of Birmingham, 2013. http://etheses.bham.ac.uk//id/eprint/4479/.

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The world-wide application of Phasor Measurement Units (PMUs) brings great benefit to power system state estimation. The synchronised measurements from PMUs can increase estimation accuracy, synchronise states among different systems, and provide greater applicability of state estimation in the transient condition. However, the integration of synchronised measurements with state estimation can introduce efficiency problems due to the substantial burden of data. The research is divided into two parts: finding a solution to cope with the computational efficiency problem and developing a transient state estimation algorithm based on synchronised measurements from PMUs. The computational efficiency problems constitute important considerations in the operation of state estimation. To improve the low computational efficiency, two distributed algorithms are proposed in Chapters 4 and 5. In these two algorithms, the modelling, structure, and solution are described, and the corresponding procedures of bad data processing are presented. Numerical results on the IEEE 30-bus, 118-bus and 300-bus systems can verify the effectiveness of the two proposed algorithms. A novel transient state estimation algorithm based on synchronised measurements is proposed in Chapter 6. Considering the scanning cycle and sampling rate of PMU measurements, the proposed algorithm can estimate transient states in a practical way. The performance of the proposed algorithm is demonstrated in a transient simulation on the IEEE 14-bus system.

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Nuqui, Reynaldo Francisco. "State Estimation and Voltage Security Monitoring Using Synchronized Phasor Measurements". Diss., Virginia Tech, 2001. http://hdl.handle.net/10919/28266.

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The phasor measurement unit (PMU) is considered to be one of the most important measuring devices in the future of power systems. The distinction comes from its unique ability to provide synchronized phasor measurements of voltages and currents from widely dispersed locations in an electric power grid. The commercialization of the global positioning satellite (GPS) with accuracy of timing pulses in the order of 1 microsecond made possible the commercial production of phasor measurement units. Simulations and field experiences suggest that PMUs can revolutionize the way power systems are monitored and controlled. However, it is perceived that costs and communication links will affect the number of PMUs to be installed in any power system. Furthermore, defining the appropriate PMU system application is a utility problem that must be resolved. This thesis will address two key issues in any PMU initiative: placement and system applications. A novel method of PMU placement based on incomplete observability using graph theoretic approach is proposed. The objective is to reduce the required number of PMUs by intentionally creating widely dispersed pockets of unobserved buses in the network. Observable buses enveloped such pockets of unobserved regions thus enabling the interpolation of the unknown voltages. The concept of depth of unobservability is introduced. It is a general measure of the physical distance of unobserved buses from those known. The effects of depth of unobservability on the number of PMU placements and the errors in the estimation of unobserved buses will be shown. The extent and location of communication facilities affects the required number and optimal placement of PMUs. The pragmatic problem of restricting PMU placement only on buses with communication facilities is solved using the simulated annealing (SA) algorithm. SA energy functions are developed so as to minimize the deviation of communication-constrained placement from the ideal strategy as determined by the graph theoretic algorithm. A technique for true real time monitoring of voltage security using synchronized phasor measurements and decision trees is presented as a promising system application. The relationship of widening bus voltage angle separation with network stress is exploited and its connection to voltage security and margin to voltage collapse established. Decision trees utilizing angle difference attributes are utilized to classify the network voltage security status. It will be shown that with judicious PMU placement, the PMU angle measurement is equally a reliable indicator of voltage security class as generator var production. A method of enhancing the weighted least square state estimator (WLS-SE) with PMU measurements using a non-invasive approach is presented. Here, PMU data is not directly inputted to the WLS estimator measurement set. A separate linear state estimator model utilizing the state estimate from WLS, as well as PMU voltage and current measurement is shown to enhance the state estimate. Finally, the mathematical model for a streaming state estimation will be presented. The model is especially designed for systems that are not completely observable by PMUs. Basically, it is proposed to estimate the voltages of unobservable buses from the voltages of those observable using interpolation. The interpolation coefficients (or the linear state estimators, LSE) will be calculated from a base case operating point. Then, these coefficients will be periodically updated using their sensitivities to the unobserved bus injections. It is proposed to utilize the state from the traditional WLS estimator to calculate the injections needed to update the coefficients. The resulting hybrid estimator is capable of producing a streaming state of the power system. Test results show that with the hybrid estimator, a significant improvement in the estimation of unobserved bus voltages as well as power flows on unobserved lines is achieved.
Ph. D.

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Wehbe, Yasser. "Model Estimation of Electric Power Systems by Phasor Measurement Units Data". Scholar Commons, 2012. http://scholarcommons.usf.edu/etd/4419.

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This dissertation tackles the online estimation of synchronous machines' power subsystems electromechanical models using the output based Phasor Measurements Units (PMUs) data while disregarding any inside data. The research develops state space models and estimates their parameters and states. The research tests the developed algorithms against models of a higher and of the same complexity as the estimated models. The dissertation explores two estimations approaches using the PMUs data: i)non-linear Kalman ﬁlters namely the Extended Kalman Filter (EKF) and then the Unscented Kalman Filter (UKF) and ii) Least Squares Estimation (LSE) with Finite Diﬀerences (FN) and then with System Identiﬁcation. The EKF based research i) establishes a decoupling technique for the subsystem the rest of the power system ii) ﬁnds the maximum number of parameters to estimate for classical machine model and iii) estimates such parameters . The UKF based research i) estimates a set of electromechanical parameters and states for the ﬂux decay model and ii) shows the advantage of using a dual estimation ﬁlter with colored noise to solve the diﬃculty of some simultaneous state and parameter estimation. The LSE with FN estimation i) evaluates numerically the state space diﬀerential equations and transform the problem to an overestimated linear system whose parameters can be estimated, ii) carries out sensitivity studies evaluating the impact of operating conditions and iii) addresses the requirements for implementation on real data taken from the electric grid of the United States. The System Identiﬁcation method i) develops a linearized electromechanical model, ii) completes a parameters sub-set selection study using si8ngular values decomposition, iii) estimates the parameters of the proposed model and iv) validates its output versus the measured output.

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Tuku, Woldu. "Distributed state estimation using phasor measurement units (PMUs)for a system snapshot". Kansas State University, 2012. http://hdl.handle.net/2097/14129.

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Master of Science
Department of Electrical and Computer Engineering
Noel N. Schulz
As the size of electric power systems are increasing, the techniques to protect, monitor and control them are becoming more sophisticated. Government, utilities and various organizations are striving to have a more reliable power grid. Various research projects are working to minimize risks on the grid. One of the goals of this research is to discuss a robust and accurate state estimation (SE) of the power grid. Utilities are encouraging teams to change the conventional way of state estimation to real time state estimation. Currently most of the utilities use traditional centralized SE algorithms for transmission systems. Although the traditional methods have been enhanced with advancement in technologies, including PMUs, most of these advances have remained localized with individual utility state estimation. There is an opportunity to establish a coordinated SE approach integration using PMU data across a system, including multiple utilities and this is using Distributed State Estimation (DSE). This coordination will minimize cascading effects on the power system. DSE could be one of the best options to minimize the required communication time and to provide accurate data to the operators. This project will introduce DSE techniques with the help of PMU data for a system snapshot. The proposed DSE algorithm will split the traditional central state estimation into multiple local state estimations and show how to reduce calculation time compared with centralized state estimation. Additionally these techniques can be implemented in micro-grid or islanded system.

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Libri sul tema "Phasor estimation"

Singh, Hema, R. Chandini e Rakesh Mohan Jha. RCS Estimation of Linear and Planar Dipole Phased Arrays: Approximate Model. Singapore: Springer Singapore, 2016. http://dx.doi.org/10.1007/978-981-287-754-3.

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Time-frequency analysis and synthesis of linear signal spaces: Time-frequency filters, signal detection and estimation, and range-Doppler estimation. Boston: Kluwer Academic Publishers, 1998.

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Manning, Robert Michael. Real-time in situ signal-to-noise ratio estimation for the assessment of operational communications links. [Cleveland, Ohio]: National Aeronautics and Space Administration, Glenn Research Center, 2002.

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Lundin, Fredrik. Case studies in omniparametric simulation. Go̊teborg, Sweden: Dept. of Mathematical Sciences, Chalmers University of Technology and Göteborg University, 2006.

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Laari, Arto. Gas-liquid mass transfer in bubbly flow: Estimation of mass transfer, bubble size and reactor performance in various applications. Lappeenranta: Lappeenranta University of Technology, 2005.

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R, Kumar. A novel multistage estimation of the signal parameters of a possibly data-modulated sinusoid under very high dynamics. Pasadena, Calif: National Aeronautics and Space Administration, Jet Propulsion Laboratory, California Institute of Technology, 1989.

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Satdarova, Faina. DIFFRACTION ANALYSIS OF DEFORMED METALS: Theory, Methods, Programs. xxu: Academus Publishing, 2019. http://dx.doi.org/10.31519/monography_1598.

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General analysis of the distribution of crystals orientation and dislocation density in the polycrystalline system is presented. Recovered information in diffraction of X-rays adopting is new to structure states of polycrystal. Shear phase transformations in metals — at the macroscopic and microscopic levels — become a clear process. Visualizing the advances is produced by program included in package delivered. Mathematical models developing, experimental design, optimal statistical estimation, simulation the system under study and evolution process on loading serves as instrumentation. To reduce advanced methods to research and studies problem-oriented software will promote when installed. Automation programs passed a testing in the National University of Science and Technology “MISIS” (The Russian Federation, Moscow). You score an advantage in theoretical and experimental research in the field of physics of metals.

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Capitoli di libri sul tema "Phasor estimation"

Phadke, A. G., e J. S. Thorp. "Phasor Estimation of Nominal Frequency Inputs". In Power Electronics and Power Systems, 29–48. Boston, MA: Springer US, 2008. http://dx.doi.org/10.1007/978-0-387-76537-2_2.

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Phadke, Arun G., e James S. Thorp. "Phasor Estimation of Nominal Frequency Inputs". In Power Electronics and Power Systems, 29–45. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-50584-8_2.

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Phadke, A. G., e J. S. Thorp. "Phasor Estimation at Off-Nominal Frequency Inputs". In Power Electronics and Power Systems, 49–79. Boston, MA: Springer US, 2008. http://dx.doi.org/10.1007/978-0-387-76537-2_3.

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Phadke, Arun G., e James S. Thorp. "Phasor Estimation at Off-Nominal Frequency Inputs". In Power Electronics and Power Systems, 47–72. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-50584-8_3.

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Jordaan, Jaco, Anton van Wyk e Ben van Wyk. "Nonparametric Time-Varying Phasor Estimation Using Neural Networks". In Neural Information Processing, 693–702. Berlin, Heidelberg: Springer Berlin Heidelberg, 2008. http://dx.doi.org/10.1007/978-3-540-69162-4_72.

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Shankar, Shiv, Vishal Rathore, K. B. Yadav e Alok Priyadarshi. "State Estimation of Power Network Using Phasor Measurement". In Lecture Notes in Electrical Engineering, 63–74. Singapore: Springer Nature Singapore, 2022. http://dx.doi.org/10.1007/978-981-19-0193-5_6.

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Thiab, Omar Sami, Łukasz Nogal e Ryszard Kowalik. "Dynamic Power Systems Phasor Estimation Using Kalman Filter Algorithms". In Communications in Computer and Information Science, 110–22. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-38752-5_9.

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Aarthi, V., Ram Krishan e Himanshu Grover. "State Estimation in Active Power Distribution Systems Using Phasor Measurement Units". In Lecture Notes in Electrical Engineering, 123–39. Singapore: Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-99-0969-8_14.

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Alam, Mehebub, Shubhrajyoti Kundu, Siddhartha Sankar Thakur e Sumit Banerjee. "Transmission Line Outage Estimation Through Bus Current Comparison Utilizing Current Phasor of PMU". In Lecture Notes in Electrical Engineering, 377–89. Singapore: Springer Singapore, 2020. http://dx.doi.org/10.1007/978-981-15-7994-3_35.

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Saha, Soumili, Prateek Bose e Sarita Nanda. "Phasor Estimation of Power Signals in a Smart Grid Environment Using Sigmoid Adaptive Filter". In Lecture Notes in Electrical Engineering, 487–93. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-16-0749-3_36.

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Atti di convegni sul tema "Phasor estimation"

Bhonsle, J. S., e A. S. Junghare. "Phasor assisted state estimation". In 2015 International Conference on Computer, Communication and Control (IC4). IEEE, 2015. http://dx.doi.org/10.1109/ic4.2015.7375587.

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Paternina, M. R. A., A. Zamora, M. Ernesto Vazquez e Juan M. Ramirez. "Phasor estimation under transient conditions". In 2015 IEEE Eindhoven PowerTech. IEEE, 2015. http://dx.doi.org/10.1109/ptc.2015.7232242.

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Daoud, George, Hany Selim e Mohamed M. AbdelRaheem. "Micro Phasor Measurement Unit Phasor Estimation by off-Nominal Frequency". In 2018 IEEE International Conference on Smart Energy Grid Engineering (SEGE). IEEE, 2018. http://dx.doi.org/10.1109/sege.2018.8499506.

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Jones, Kevin D., James S. Thorp e R. Matthew Gardner. "Three-phase linear state estimation using Phasor Measurements". In 2013 IEEE Power & Energy Society General Meeting. IEEE, 2013. http://dx.doi.org/10.1109/pesmg.2013.6672516.

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Abur, Ali, e Floyd Galvan. "Synchro-Phasor Assisted State Estimation (SPASE)". In 2012 IEEE PES Innovative Smart Grid Technologies (ISGT). IEEE, 2012. http://dx.doi.org/10.1109/isgt.2012.6175559.

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Patel, Tapas Kumar, Sarat Chandra Swain, Prafulla Chandra Panda e Subodh Kumar Mohanty. "Accurate phasor estimation during power swing". In 2017 Innovations in Power and Advanced Computing Technologies (i-PACT). IEEE, 2017. http://dx.doi.org/10.1109/ipact.2017.8244911.

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Sodhi, Ranjana, S. C. Srivastava e S. N. Singh. "Teager energy based dynamic phasor estimation". In 2012 Annual IEEE India Conference (INDICON). IEEE, 2012. http://dx.doi.org/10.1109/indcon.2012.6420792.

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Kovacic, Marko, Marko Jurcevic, Roman Malaric e Antonijo Kunac. "A Review of Phasor Estimation Algorithms". In 2020 3rd International Colloquium on Intelligent Grid Metrology (SMAGRIMET). IEEE, 2020. http://dx.doi.org/10.23919/smagrimet48809.2020.9264012.

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Rao, J. Ganeswara, e Ashok Kumar Pradhan. "Accurate phasor estimation during power swing". In 2016 IEEE Power and Energy Society General Meeting (PESGM). IEEE, 2016. http://dx.doi.org/10.1109/pesgm.2016.7741201.

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Vats, Mansi, e Sangeeta Kamboj. "Application of phasor & frequency estimation techniques in phasor measurement unit". In 2016 7th India International Conference on Power Electronics (IICPE). IEEE, 2016. http://dx.doi.org/10.1109/iicpe.2016.8079490.

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Rapporti di organizzazioni sul tema "Phasor estimation"

Choquette, Gary, e Nolan Choquette. PR-000-16600-R01 Correlative Estimation of Hydrocarbon Dewpoint. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), settembre 2019. http://dx.doi.org/10.55274/r0011618.

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Simplified methods to estimate the hydrocarbon cricondentherm hydrocarbon dewpoint temperature and the associated phase curve are desirable in cases with limited processor power/memory or in cases where full gas composition analysis information is not available. This study developed and evaluated several methods to provide reasonable estimates of hydrocarbon dew-point temperature and the phase curve using simplified correlation methods.

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Peters, Keith, e Steven Kay. Unbiased Estimation of the Phase of a Sinusoid. Fort Belvoir, VA: Defense Technical Information Center, gennaio 2002. http://dx.doi.org/10.21236/ada525814.

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Cumming, I. G., F. Wong e R. K. Hawkins. RADARSAT Doppler Centroid Estimation Using Phase-Based Estimators. Natural Resources Canada/ESS/Scientific and Technical Publishing Services, 1999. http://dx.doi.org/10.4095/219627.

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Blampied, Nigel, Tariq Shehab, Elhami Nasr e Laxmi Sindhu Samudrala. Preconstruction Support Cost Hours Estimating on Caltrans Pavement Rehabilitation Projects. Mineta Transportation Institute, maggio 2023. http://dx.doi.org/10.31979/mti.2023.2148.

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Because the construction phase accounts for the majority of project costs for pavement rehabilitation projects, most research on infrastructure project cost estimating focuses on that phase, rather than on the preconstruction phases. Nevertheless, costs incurred prior to construction, referred to in this report as "preconstruction costs" are significant and worthy of consideration (See Section 2.1 of the report for a more detailed and precise definition of preconstruction). In the 20202021 fiscal year, for instance, the California Department of Transportation (Caltrans) spent more than $169 million on preconstruction work for pavement rehabilitation projects. This report presents the results of a study of preconstruction cost estimating for pavement rehabilitation projects undertaken by Caltrans. It uses data on the 139 pavement rehabilitation projects for which Caltrans opened bids in the five-year period from April 26, 2016 to May 11, 2021. A data set was developed that combined the preconstruction hours for each project with the primary bid items for the pavement rehabilitation projects. Two models were developed to estimate preconstruction hours from the bid items, one using an Artificial Neural Network (ANN) and the other a parametric exponential model developed using multiple regression. The models had coefficients of determination of 0.85 and 0.80, respectively. Tools were then developed to assist professional users in validating their preconstruction cost estimates using each of the models. CTC staff or Caltrans can use these tools to evaluate the reasonableness of the preconstruction estimate on an individual project, or on the sum of an entire biennial SHOPP pavement rehabilitation portfolio, in order to assure the most efficient use of infrastructure funding to best serve the community's transportation needs.

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Teti, Joseph G., e Jr. Basic Concepts of Spectral Estimation Using a Uniform Linear Phased Array. Fort Belvoir, VA: Defense Technical Information Center, settembre 1988. http://dx.doi.org/10.21236/ada325809.

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Neuert, Mark, e Smitha Koduru. PR-244-173856-R01 In-line Inspection Crack Tool Reliability and Performance Evaluation. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), giugno 2019. http://dx.doi.org/10.55274/r0011599.

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The ability for operators to make operational and maintenance decisions based on in-line inspection (ILI) data depends on the performance of ILI tools with respect to sizing and detection of crack and stress corrosion cracking (SCC) features. A series of previous Pipeline Research Council International, Inc. (PRCI) projects created a database of ILI tool and pipe excavation data that can be used to evaluate the detection and sizing capabilities of ultrasonic (UT) (NDE-4-E Phase 1, PR-244-133731) and electromagnetic acoustic (EMAT) (NDE-4-E Phase 2, PR-244-153719) ILI technologies. This current project, NDE-4-7 (PR-244-173856), was carried out by C-FER Technologies (1999) Inc. (C-FER) for PRCI. It is Phase 3 of an ongoing industry-wide effort to understand and characterize ILI tool performance. In addition to adding a new data set to the database developed in Phases 1 and 2, estimates of ILI tool performance with respect to rate of detection (ROD), probability of identification (POI), false discovery rate (FDR), and sizing accuracy (SA) were calculated. Two further analyses were performed, namely an investigation of the effect of crack profile data on tool performance and burst pressure estimation, and an evaluation of the reduction in sizing uncertainty attained through multiple measurements of crack features. This document has a related webinar.

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Bajwa, Abdullah, Tim Kroeger e Timothy Jacobs. PR-457-17201-R04 Residual Gas Fraction Estimation Based on Measured Engine Parameters - Phase IV. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), settembre 2021. http://dx.doi.org/10.55274/r0012176.

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Based on experimental characterization of the scavenging behavior of a cross-scavenged, piston-aspirated, two-stroke, natural gas engine in phase III of the current project, a computationally inexpensive simple scavenging model was improved in this phase. Experimental results using fast nondispersive infrared (NDIR) CO2 measurements from the cylinder and the exhaust, as well as experiments using unburned fuel pre-mixed in the scavenging chamber as a tracer for short-circuiting during scavenging, were used in this phase to validate the improved model. The model represents the fundamental phenomenological characteristics revealed by those experiments. The experiments and literature show that scavenging takes place by the following phenomena: blowdown, displacement of residuals by incoming air, mixing of residuals and air, and short-circuiting of fresh air. To reflect this, the improved hybrid model features the following: isentropic blowdown, non-isothermal perfect displacement, non-isothermal perfect mixing, and a concurrent direct short-circuiting of air (unmixed with residuals). The validated improved hybrid model rectified the primary shortcoming of the phase III model. By adding the discrete short-circuiting zone, trapped mass could be modeled at both medium and high crankshaft speeds, whereas the phase III model could not capture the full scope of scavenging inefficiencies at medium speed using its perfect mixing stage alone. Furthermore, using the hybrid model to predict NOx using an exponential NO and shy;x-TER curve fit revealed that the improved phase IV hybrid model predicts NOx approximately as well as the experimentally-calculated TER from the phase III experiments. Additionally, GT-Power, a 1D fluid dynamics and engine simulation software, was used to identify whether hybrid model tuning could be aided by relatively inexpensive 1D simulation rather than CFD or fast NDIR experiments. Using three-pressure analysis (with in-cylinder, exhaust, and scavenging chamber pressures as boundary conditions) and scavenging profiles derived from the hybrid model itself, GT-Power was shown to be a plausible tool for scavenging model tuning.

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Maes, Marc. PR-328-133600-R02 Probabilistic Corrosion Growth Models and ILI-Based Estimation Procedures - Phase II. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), aprile 2015. http://dx.doi.org/10.55274/r0010842.

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The overall objective of Phase II covered by the present report, has been to implement the preferred Phase I stochastic metal loss analysis model in an effective self-standing Excel tool for matched repeat ILI data: the Hierarchical Stochastic Corrosion Growth Model (HSCGM). This analysis tool can deal with up to 5 repeat inspections and up to 1,000 (hierarchical) defects. It is a deliverable of this Project and it has been satisfactory verified and tested; its main mission is to allow flawless experimentation with the practical use of consistent stochastic metal loss processes in the context of repeat ILI inspections for pipeline integrity assessment, to explore its numerous analysis options, features, and results in the context of CGRs for pipeline integrity assessment. This report provides all the details and technical features of the HSCGM analysis tool, based on the Bayesian stochastic process approach described in the Phase I report.

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Bajwa, Abdullah, e Timothy Jacobs. PR-457-17201-R01 Residual Gas Fraction Estimation Based on Measured In-Cylinder Pressure. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), settembre 2018. http://dx.doi.org/10.55274/r0011519.

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Developing a reliable means of predicting and controlling engine operation at various operating conditions may be a reasonable pathway for meeting increasingly stringent engine emission regulations. In order to do so, estimates of the mixture composition at the end of the gas exchange process (i.e. at exhaust port closure, or EPC) are helpful for having accurate models of engine combustion. A substantial fraction of the trapped charge mixture is composed of residual gases from previous cycles. This fraction, the trapped residual fraction, changes combustion characteristics of the trapped mixture. Residual gases dilute the fresh charge, thus decreasing the flame speed and temperature. Moreover, because of their spatial inhomogeneity, especially around the spark plug, these gases seem to have implications for engine stability. All these factors likely affect engine performance and emissions. Unfortunately, it is not practical to directly measure the trapped residual fraction for engines operating in the field. To overcome this, computational models can be developed for control applications which estimate this fraction based on some measurable engine parameters e.g. manifold pressures, temperatures, etc. Currently, such models aren't readily available for stationary two-stroke natural-gas engines. This report summarizes the results of phase I of a multi-phase project. In this phase a GT-Power based model was developed for an Ajax E-565 single-cylinder engine to study various factors that influence the removal, or lack thereof, of residual gases from the engine cylinder. The model was used to successfully simulate various engine operating conditions and study the scavenging characteristics of the engine. Various steps followed in the development of the model have been discussed in the report, and at the end some preliminary results and recommendations for the next phase of the project have been presented.

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Borden, Brett, e R. J. Dinger. Radar Inverse Scattering Using Statistical Estimation of the Echo Phase- Front Derivatives. Fort Belvoir, VA: Defense Technical Information Center, novembre 1986. http://dx.doi.org/10.21236/ada176598.

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