2020 International Conference on Power, Instrumentation, Control and Computing (PICC), 2020
This paper focuses on closed loop operational mode of Volt-VAr control (VVC) algorithm, as well a... more This paper focuses on closed loop operational mode of Volt-VAr control (VVC) algorithm, as well as the power flow (PF) methods that can successfully be used to implement VVC. Two methods to implement efficient PF are Newton-Raphson approach and current iteration approach. The paper compares both approaches to find the one most suitable for the implementation of closed loop VVC algorithm.
2021 7th International Conference on Electrical Energy Systems (ICEES), 2021
This paper describes the usage of voltage VAr control (VVC) in closed loop mode (CLVVC). The focu... more This paper describes the usage of voltage VAr control (VVC) in closed loop mode (CLVVC). The focus is the application in single feeder radial distribution systems, where the CLVVC is executed in combination with short term load forecast (STLF) and distribution system state estimation (DSSE). Although well-known benefits, this paper especially deals with pitfalls and drawbacks of implementing and using closed loop.
2021 7th International Conference on Electrical Energy Systems (ICEES), 2021
Concurrently with the electrification of many segments of modern life, such as transport and heat... more Concurrently with the electrification of many segments of modern life, such as transport and heating, the problem of short term load forecasting becomes more actual and important. For each power system management, it is crucial to have parameters that display how much electricity is consumed and generated, so the estimation of future consumption can be developed. During the last years, short term load forecast is obtained by various methodologies; each presenting their advantages compared to the others. In this paper we investigate the feasibility of short term load forecasting using dynamic mode decomposition (DMD). The main idea is to model the consumption space as a linear dynamic system using the measured data. A test data-set is collected from 2009 to 2011 in Ireland, consumption of power was recorded every half hour, the experiments performed by manipulating data, and arranging it for easier application of the algorithm. It is shown that using timestamps with DMD provides easy...
2020 2nd Global Power, Energy and Communication Conference (GPECOM), 2020
Ungrounded and high resistance grounded lines are utilized in distribution networks, and in speci... more Ungrounded and high resistance grounded lines are utilized in distribution networks, and in special transmission networks. The fault current of a line to ground fault is not high enough to activate protective equipment, hence, the power delivery is not interrupted. Pre-fault and fault currents are available after fault occurs. Thus, used for compensation of pre-fault signals, then filtered using a low pass filter. This allows the introduction of a robust and accurate algorithm for locating single line to ground faults in such ungrounded networks. The algorithm uses symmetrical components extracted from filtered and compensated signals on both ends of a line for an initial estimate of fault location. The fine tuned location is determined by solving nonlinear least square problem that imposes equality constraints related to physical attributes of the fault. The details of the algorithm are already published. In this paper we provide an in depth overview of the algorithm and some numer...
The paper presents geometrical methodology of determining pose angle of an object against SAR ima... more The paper presents geometrical methodology of determining pose angle of an object against SAR images stored in a data base. The images are separated by a pose angle (less than 2°), obtained from an air surveillance plane at a depression angle and at a distance, producing SAR images of 1 × 1 foot pixel resolution. The data base is public (US Government) for academic and defense research. The data base consists of 100s of commercial and military vehicles, as well as building structures. In this paper, we focus on three targets which have symmetric geometry, each of different size and shape. In addition, we also generate several synthetic targets of various symmetric shapes to serve as the ideal test cases. The analysis is based on simple geometrical considerations as well as edge and surface area determination using number of SAR signatures pixels. The overall methodology aims at significantly reducing data base search space to produce an effective and fast computationally viable sear...
The paper presents a second part of the paper: Automatic SAR Target Recognition and Pose Estimati... more The paper presents a second part of the paper: Automatic SAR Target Recognition and Pose Estimation, in which we analyze ATR, automatic target recognition. The first part deals with pose angle determination and target data base search space reduction using a variety of geometrical methods. Both papers use US Government MSTAR, public target data base released for academic research and development. SAR target images are separated by a small pose angle (between 1° and 2°). They are obtained form an air surveillance moving plane platform at a certain depression angle and at a certain distance which all produce SAR images of 1 × 1 foot pixel resolution. The objects (targets) data base consists of 100s of commercial and military vehicles, as well as wall and building structures. We focus on three typical targets which have symmetric geometry, each of different size and shape. In addition to these three real targets we also generate several synthetic targets of various symmetric shapes to ...
The continuity of service in power systems has a vital economical and social impact on all shareh... more The continuity of service in power systems has a vital economical and social impact on all shareholders; generation, transmission and distribution, and end users. Fault classification within transmission and distribution networks plays an important role in power restoration for guaranteed service continuity. With advances in digital signal processing in terms of speed and algorithms, the use of wavelets transform is made easy and feasible for real-time applications in power systems. In this paper we present two methods of fault classification using Discrete Wavelet Transforms (DWT). The coefficients of the wavelet decomposition of fault signals are correlated with the coefficients of signals in normal working conditions to deduce fault information. Haar wavelets and multi-resolution analysis are used for detecting the faulty phase while Daubechies wavelet is used to determine if the fault to ground or not. Both suggested methods succeeded in all types of faults simulated using Simul...
This paper presents a method for locating ground faults in ungrounded and high resistance grounde... more This paper presents a method for locating ground faults in ungrounded and high resistance grounded networks. In such networks, the contribution of the fault to the line currents is minimal, thus creating a challenge to the popular impedance-based fault locators employed in the industry. A compensation method is introduced to alleviate this impediment to the use of impedance-based fault locators; the compensated signals are consistent with the transmission line wave equations and are formed by the fault signal components thus making the fault information more visible. The proposed approach employs (i) phasor extraction based on forward and backward finite impulse response (FIR) filtering to better capture the fault signal dynamics, (ii) an initialization stage employing redundant measurement equations of the fault voltage, and (iii) an augmented matrix approach for least-squares estimation that models the physical conditions of the fault in symmetrical component coordinates. The prop...
High quality inverse scattering based scanner for pavement nondestructive testing needs a high pe... more High quality inverse scattering based scanner for pavement nondestructive testing needs a high performance antenna with certain characteristics. This paper considers an UWB antipodal Vivaldi antenna for this application. Simulation results for the targeted frequency range obtained through the use of Sonnet modeling software show that this antenna is characterized by a good match over the broad frequency range as well as a frequency dependent gain. The antenna performance has also been analyzed in the near field by considering tangential electric fields in the close proximity of the radiating structure. The antenna described in this paper is a part of a larger research project with a goal to develop a scanning device based on inverse scattering methods and used for accurate, non-destructive, and inexpensive characterization of road pavements. The system will use a state-of-the-art, fast and accurate numerical solver for 3D inverse scattering problems in stratified media. The solver w...
Fault location is one of the most common aspects of power system analysis and protection. In orde... more Fault location is one of the most common aspects of power system analysis and protection. In order to maintain system's stability and avoid long lasting blackouts, it is important to localize a fault in shortest possible time. This paper analyzes already published impedance-based fault location methods and suggests new algorithm based on orthogonal components. Proposed method is applied on Simulink created three phase model, considering various system specifications including different fault resistance values, having more than one fault on a line at different locations, grounded and ungrounded generators effects, sampling rate changes, line length effects, etc. The results are indicating good accuracy of the algorithm itself.
Ground Moving Target Indicator (GMTI) and High Resolution Radar (HRR) can track position and velo... more Ground Moving Target Indicator (GMTI) and High Resolution Radar (HRR) can track position and velocity of ground moving target. Pose, angle between position and velocity, can be derived from estimates of position and velocity and it is often used to reduce the search space and hence increase likelihood of target identification (ID) and Automatic Target Recognition (ATR) algorithms. Due to low resolution in some radar systems, the GMTI estimated pose may exhibit large errors contributing to a faulty identification of potential targets. Our goal in this paper is to define better methodology to improve pose estimate, using real time target signature versus stored signatures. Besides applications in target tracking, there are numerous commercial applications in machine learning, augmented reality and body tracking.
This paper presents a digital signal processing technique with an efficient algorithm for ultraso... more This paper presents a digital signal processing technique with an efficient algorithm for ultrasonic distance measurement in the air with high accuracy. The time difference -in terms of samples- between the beginning of a transmitted pulse and the peak value of the response is used to determine the Time-of-Flight (TOF). The peak value of the filtered response is determined using
This paper presents a combined application of fast Fourier transform (FFT) and the Mexican hat wa... more This paper presents a combined application of fast Fourier transform (FFT) and the Mexican hat wavelet for fault detection within distribution networks. The short time fast Fourier transform (STFFT) can replace FFT as well. One of the two Fourier transforms is used to determine the high frequency harmonics due to abrupt changes in line currents, those harmonics take place when various faults occur. The Mexican hat wavelet is used with a scaling factor which is found based on the frequency of the harmonics and the sampling rate of the measurement device. The results show good performance of the suggested approach, and the next step would be the classification of the fault type.
2020 International Conference on Power, Instrumentation, Control and Computing (PICC), 2020
This paper focuses on closed loop operational mode of Volt-VAr control (VVC) algorithm, as well a... more This paper focuses on closed loop operational mode of Volt-VAr control (VVC) algorithm, as well as the power flow (PF) methods that can successfully be used to implement VVC. Two methods to implement efficient PF are Newton-Raphson approach and current iteration approach. The paper compares both approaches to find the one most suitable for the implementation of closed loop VVC algorithm.
2021 7th International Conference on Electrical Energy Systems (ICEES), 2021
This paper describes the usage of voltage VAr control (VVC) in closed loop mode (CLVVC). The focu... more This paper describes the usage of voltage VAr control (VVC) in closed loop mode (CLVVC). The focus is the application in single feeder radial distribution systems, where the CLVVC is executed in combination with short term load forecast (STLF) and distribution system state estimation (DSSE). Although well-known benefits, this paper especially deals with pitfalls and drawbacks of implementing and using closed loop.
2021 7th International Conference on Electrical Energy Systems (ICEES), 2021
Concurrently with the electrification of many segments of modern life, such as transport and heat... more Concurrently with the electrification of many segments of modern life, such as transport and heating, the problem of short term load forecasting becomes more actual and important. For each power system management, it is crucial to have parameters that display how much electricity is consumed and generated, so the estimation of future consumption can be developed. During the last years, short term load forecast is obtained by various methodologies; each presenting their advantages compared to the others. In this paper we investigate the feasibility of short term load forecasting using dynamic mode decomposition (DMD). The main idea is to model the consumption space as a linear dynamic system using the measured data. A test data-set is collected from 2009 to 2011 in Ireland, consumption of power was recorded every half hour, the experiments performed by manipulating data, and arranging it for easier application of the algorithm. It is shown that using timestamps with DMD provides easy...
2020 2nd Global Power, Energy and Communication Conference (GPECOM), 2020
Ungrounded and high resistance grounded lines are utilized in distribution networks, and in speci... more Ungrounded and high resistance grounded lines are utilized in distribution networks, and in special transmission networks. The fault current of a line to ground fault is not high enough to activate protective equipment, hence, the power delivery is not interrupted. Pre-fault and fault currents are available after fault occurs. Thus, used for compensation of pre-fault signals, then filtered using a low pass filter. This allows the introduction of a robust and accurate algorithm for locating single line to ground faults in such ungrounded networks. The algorithm uses symmetrical components extracted from filtered and compensated signals on both ends of a line for an initial estimate of fault location. The fine tuned location is determined by solving nonlinear least square problem that imposes equality constraints related to physical attributes of the fault. The details of the algorithm are already published. In this paper we provide an in depth overview of the algorithm and some numer...
The paper presents geometrical methodology of determining pose angle of an object against SAR ima... more The paper presents geometrical methodology of determining pose angle of an object against SAR images stored in a data base. The images are separated by a pose angle (less than 2°), obtained from an air surveillance plane at a depression angle and at a distance, producing SAR images of 1 × 1 foot pixel resolution. The data base is public (US Government) for academic and defense research. The data base consists of 100s of commercial and military vehicles, as well as building structures. In this paper, we focus on three targets which have symmetric geometry, each of different size and shape. In addition, we also generate several synthetic targets of various symmetric shapes to serve as the ideal test cases. The analysis is based on simple geometrical considerations as well as edge and surface area determination using number of SAR signatures pixels. The overall methodology aims at significantly reducing data base search space to produce an effective and fast computationally viable sear...
The paper presents a second part of the paper: Automatic SAR Target Recognition and Pose Estimati... more The paper presents a second part of the paper: Automatic SAR Target Recognition and Pose Estimation, in which we analyze ATR, automatic target recognition. The first part deals with pose angle determination and target data base search space reduction using a variety of geometrical methods. Both papers use US Government MSTAR, public target data base released for academic research and development. SAR target images are separated by a small pose angle (between 1° and 2°). They are obtained form an air surveillance moving plane platform at a certain depression angle and at a certain distance which all produce SAR images of 1 × 1 foot pixel resolution. The objects (targets) data base consists of 100s of commercial and military vehicles, as well as wall and building structures. We focus on three typical targets which have symmetric geometry, each of different size and shape. In addition to these three real targets we also generate several synthetic targets of various symmetric shapes to ...
The continuity of service in power systems has a vital economical and social impact on all shareh... more The continuity of service in power systems has a vital economical and social impact on all shareholders; generation, transmission and distribution, and end users. Fault classification within transmission and distribution networks plays an important role in power restoration for guaranteed service continuity. With advances in digital signal processing in terms of speed and algorithms, the use of wavelets transform is made easy and feasible for real-time applications in power systems. In this paper we present two methods of fault classification using Discrete Wavelet Transforms (DWT). The coefficients of the wavelet decomposition of fault signals are correlated with the coefficients of signals in normal working conditions to deduce fault information. Haar wavelets and multi-resolution analysis are used for detecting the faulty phase while Daubechies wavelet is used to determine if the fault to ground or not. Both suggested methods succeeded in all types of faults simulated using Simul...
This paper presents a method for locating ground faults in ungrounded and high resistance grounde... more This paper presents a method for locating ground faults in ungrounded and high resistance grounded networks. In such networks, the contribution of the fault to the line currents is minimal, thus creating a challenge to the popular impedance-based fault locators employed in the industry. A compensation method is introduced to alleviate this impediment to the use of impedance-based fault locators; the compensated signals are consistent with the transmission line wave equations and are formed by the fault signal components thus making the fault information more visible. The proposed approach employs (i) phasor extraction based on forward and backward finite impulse response (FIR) filtering to better capture the fault signal dynamics, (ii) an initialization stage employing redundant measurement equations of the fault voltage, and (iii) an augmented matrix approach for least-squares estimation that models the physical conditions of the fault in symmetrical component coordinates. The prop...
High quality inverse scattering based scanner for pavement nondestructive testing needs a high pe... more High quality inverse scattering based scanner for pavement nondestructive testing needs a high performance antenna with certain characteristics. This paper considers an UWB antipodal Vivaldi antenna for this application. Simulation results for the targeted frequency range obtained through the use of Sonnet modeling software show that this antenna is characterized by a good match over the broad frequency range as well as a frequency dependent gain. The antenna performance has also been analyzed in the near field by considering tangential electric fields in the close proximity of the radiating structure. The antenna described in this paper is a part of a larger research project with a goal to develop a scanning device based on inverse scattering methods and used for accurate, non-destructive, and inexpensive characterization of road pavements. The system will use a state-of-the-art, fast and accurate numerical solver for 3D inverse scattering problems in stratified media. The solver w...
Fault location is one of the most common aspects of power system analysis and protection. In orde... more Fault location is one of the most common aspects of power system analysis and protection. In order to maintain system's stability and avoid long lasting blackouts, it is important to localize a fault in shortest possible time. This paper analyzes already published impedance-based fault location methods and suggests new algorithm based on orthogonal components. Proposed method is applied on Simulink created three phase model, considering various system specifications including different fault resistance values, having more than one fault on a line at different locations, grounded and ungrounded generators effects, sampling rate changes, line length effects, etc. The results are indicating good accuracy of the algorithm itself.
Ground Moving Target Indicator (GMTI) and High Resolution Radar (HRR) can track position and velo... more Ground Moving Target Indicator (GMTI) and High Resolution Radar (HRR) can track position and velocity of ground moving target. Pose, angle between position and velocity, can be derived from estimates of position and velocity and it is often used to reduce the search space and hence increase likelihood of target identification (ID) and Automatic Target Recognition (ATR) algorithms. Due to low resolution in some radar systems, the GMTI estimated pose may exhibit large errors contributing to a faulty identification of potential targets. Our goal in this paper is to define better methodology to improve pose estimate, using real time target signature versus stored signatures. Besides applications in target tracking, there are numerous commercial applications in machine learning, augmented reality and body tracking.
This paper presents a digital signal processing technique with an efficient algorithm for ultraso... more This paper presents a digital signal processing technique with an efficient algorithm for ultrasonic distance measurement in the air with high accuracy. The time difference -in terms of samples- between the beginning of a transmitted pulse and the peak value of the response is used to determine the Time-of-Flight (TOF). The peak value of the filtered response is determined using
This paper presents a combined application of fast Fourier transform (FFT) and the Mexican hat wa... more This paper presents a combined application of fast Fourier transform (FFT) and the Mexican hat wavelet for fault detection within distribution networks. The short time fast Fourier transform (STFFT) can replace FFT as well. One of the two Fourier transforms is used to determine the high frequency harmonics due to abrupt changes in line currents, those harmonics take place when various faults occur. The Mexican hat wavelet is used with a scaling factor which is found based on the frequency of the harmonics and the sampling rate of the measurement device. The results show good performance of the suggested approach, and the next step would be the classification of the fault type.
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Papers by Tarik Namas