C. Hatziadoniu

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Papers by C. Hatziadoniu

TIME DOMAIN METHODS FOR THE CALCULATION OF HARMONIC PROPAGATION AND DISTORTION By

Numerical methods for the computation of harmonic propagation and distortion differ in the manner... more

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Interharmonics: Theory and Modeling IEEE Task Force on Harmonics Modeling and Simulation

Abstract—Some of the most remarkable issues related to inter-harmonic theory and modeling are pre... more Abstract—Some of the most remarkable issues related to inter-harmonic theory and modeling are presented. Starting from the basic definitions and concepts, attention is first devoted to interhar-monic sources. Then, the interharmonic assessment is considered with particular attention to the problem of the frequency resolu-tion and of the computational burden associated with the analysis of periodic steady-state waveforms. Finally, modeling of different kinds of interharmonic sources and the extension of the classical models developed for power system harmonic analysis to include interharmonics are discussed. Numerical results for the issues pre-sented are given with references to case studies constituted by pop-ular schemes of adjustable speed drives. Index Terms—Discrete Fourier transform (DFT), frequency res-olution, harmonic analysis, interharmonics. I.

Time Domain Methods for the Calculation of Harmonic Propagation and Distortion

Numerical methods for the computation of harmonic propagation and distortion differ in the manner... more Numerical methods for the computation of harmonic propagation and distortion differ in the manner in which they represent the harmonic sources and the system impedance. Iterative methods (e.g. harmonic load flow) use a phasor representation of these parameters. Time domain methods, on the other hand, use a time representation of the system elements and the harmonic sources. Thus, they are generally more accurate than the iterative methods. The simplest system modeling for harmonic calculations considers rigid harmonic sources and linear system impedance [1-3]. A rigid harmonic source produces harmonics of only characteristic orders with a pre-defined and constant magnitude and phase. The linear impedance is the result of mainly transmission lines and compensation devices. A model which includes rigid harmonic sources and linear elements can be solved by an iterative method with the same accuracy as a time domain simulation. This is because a linear model has a phasor representation ...

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Using Prophet Algorithm for Pattern Recognition and Short Term Forecasting of Load Demand Based on Seasonality and Exogenous Features

2020 52nd North American Power Symposium (NAPS), 2021

As smart meters have proliferated in recent years, electrical power companies are dealing with a ... more As smart meters have proliferated in recent years, electrical power companies are dealing with a large volume of data, known as Big Data. Consistent with this issue, data science techniques are necessary to extract the patterns of consumption and forecast load at a specific area. Short-term load forecasting (STLF) models are crucial for electric utilities and play a vital role in generation planning, system operation, system security (false data detection), energy trading (buying/purchasing), reconfiguration, and contingency analysis. Nevertheless, electric consumption forecasting is challenging due to uncertainty incorporated in consumers' behavior. In this paper, we propose a comprehensive two-stage STLF method based on the Prophet Algorithm (PA). In the first stage and after data mining, load consumption patterns are extracted based on trend and seasonality features (e.g., spring, summer, autumn, winter, daily, weekly, etc.) along with holiday effects. Also, to make the model...

Probabilistic Quasi-Static Time Series Simulation for Distribution Network Planning Considering Multiple Uncertainties of PV and Load in the Presence of BESS

In this study, we propose a comprehensive and computationally efficient Probabilistic Quasi-Stati... more In this study, we propose a comprehensive and computationally efficient Probabilistic Quasi-Static Time Series (PQSTS) method in which the multiple uncertainties of forecasted load and PV data are employed in the distribution network planning problem. Additionally, inverter reactive power capability is implemented to regulate voltage in response to irradiance variation. Furthermore, a Battery Energy Storage System (BESS) is utilized along with the PV array to smooth and shave substation peak power as well as enhance system security/stability. The Non-dominated Sorting Genetic Algorithm-II combined with Fuzzy Decision-Making Tool (NSGA-II/FDMT) is implemented to solve the multi-objective problem along with three objectives: (a) minimization of distribution network power losses; (b) maximization of system security; and (c) minimization of the total cost. Also, two more indices, i.e., maximum overall voltage deviation and substation peak power, are defined to evaluate DN system perform...

Dynamics of current regulator with hysteresis control and clocked commutation in application to power electronic systems

The results of dynamics analysis of a current regulator with hysteresis control and clocked commu... more

Real-time modeling and digital implementation of fuzzy logic controllers

ICDS '95. First International Conference on Digital Power System Simulators, 1995

This paper is concerned with the numerical optimization of the Fuzzy Logic Controller (FLC) for b... more This paper is concerned with the numerical optimization of the Fuzzy Logic Controller (FLC) for both its efficient simulation and easy real-time implementation. The basic concept of the FLC based o n generalized T-operators approach has been presented. Several assumptions regarding the mathematical formalization of the FL,C have been made leading to its numerical simplification. They include: Goguen formulas for Toperators, "Center of Gravity" method for defuzzification and the overlapping between not more than two membership functions for the controllers fuzzy output. Under these assumptions, the paper presents the FLC nom-fuzzy output as the ratio of two weighted sums of certain functions of the inputs reducing the computational burden of the PLC algorithm at least few tens times comparing with the definition-based approach. The Fuzzy Logic Power System Stabilizer (PSS) has been chosen as an application example. Results of simulation studies demonstrate the efficiency of both the presented optimization method i n terms of numerical simplicity and the designed PSS i n terms of improving the power system stability.

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A Maximum Quantity Formulation of the Cournot Game for ISO/Pool Operation

2006 38th North American Power Symposium, 2006

ABSTRACT This paper studies the economic equilibrium power pool with aggregated demand, Cournot g... more ABSTRACT This paper studies the economic equilibrium power pool with aggregated demand, Cournot generators and an independent system operator with no secondary market for transmission capacity. The independent system operator manages congestion by attempting to deliver maximum quantity at least cost. The paper formulates a non-cooperative game between suppliers as a maximum total quantity problem subject to network flow constraints and supplier first order profit maximizing conditions. The paper shows that unconstrainted solutions to the proposed formulation are Nash equilibriums and supplier profits are mutually maximized. Numerical examples demonstrate a supplier selection policy that is based on their contributions to network flows. This policy will drive the network to the maximum quantity solution without further intervention.

An algorithm for transient simulation of power electronics systems

ABSTRACT The development of a general algorithm, which constructs the state equations of switchin... more ABSTRACT The development of a general algorithm, which constructs the state equations of switching systems as a function of the state of their switching elements, is presented. Although the algorithm is developed primarily for transient simulation of power electronics systems, it can be applied to any system that can be modeled by an equivalent circuit consisting of linear ERLC elements and ideal switches.

Harmonic modeling of single-phase three-level hysteresis inverters

41st North American Power Symposium, 2009

ABSTRACT The paper derives a closed-form analytical approximation of the output current harmonic ... more ABSTRACT The paper derives a closed-form analytical approximation of the output current harmonic spectrum for the three-level single-phase inverters under the action of hysteresis current control. The error current harmonic spectrum is directly calculated from the system and controller parameters. The analytical approach consists of deriving the instantaneous frequency of the error current and then approximating the error current by a frequency-modulated triangular signal. The error current harmonic spectrum reduces to a frequency convolution of two series of Bessel functions of the first kind. A truncation simplification of the output harmonic profile that is suitable for numerical calculations is also provided. MATLABSimulink© studies are presented to demonstrate the validity and accuracy of the proposed model.

Harmonic modeling and analysis of multiple residential Photo-Voltaic generators

2010 Power and Energy Conference At Illinois (PECI), 2010

ABSTRACT

Modeling of linear components for harmonic studies

This paper reviews the common practice and analytical models for the representation of aggregate ... more This paper reviews the common practice and analytical models for the representation of aggregate linear load in harmonic propagation and distortion studies. The term linear load describes a class of loads, which, if supplied by a sinusoidal source at fundamental frequency, produce only fundamental sinusoidal current. The majority of residential and commercial loads, induction motors, and synchronous motors are examples of linear load. On the other hand, electronic loads, adjustable speed drives, and arc furnaces are non-linear loads, as they generate harmonics. Linear loads are a significant component of the system harmonic impedance. They constitute the main element of damping and they may affect the resonance conditions, particularly at higher frequencies. The harmonic modeling of linear load is sensitive to load size and composition. It is difficult to establish a model based on theoretical analysis. The necessity of practical measurements on distribution points together with det...

Harmonic modeling of three-phase neutral-point inverters

The paper derives a closed-form analytical approximation of the output currents harmonic spectra ... more The paper derives a closed-form analytical approximation of the output currents harmonic spectra for the three-phase neutral-point inverters under the action of hysteresis current control. The model is an extension of the recently developed model for single-phase two-level hysteresis inverters. The model derives the instantaneous frequency of the inverter and then uses it to approximate the error currents by frequency-modulated sinusoids. The spectra of the error currents are simply the Fourier transforms of the signals' complex envelopes and are expressed in terms of Bessel functions of the first kind. The final expressions of the harmonic spectra are expressed in a suitable form for numerical calculations. MATLABSimulink© studies are presented to validate the proposed model.

Building the basis for user interactive computing in slow transient and dynamic power system studies

The authors address the problem of slow transient and dynamic simulation of power systems on pers... more The authors address the problem of slow transient and dynamic simulation of power systems on personal computers. An approach is presented for the systematic description and organization of the information and data pertaining to these studies, such as control system configuration and parameters, output selection, simulation scenario description, etc., in order to provide the basis for user interactive analysis programs. The techniques, applied to the EMTDC program, result in an autonomous executable module that permits the user to conduct the simulation studies completely through input data files. This development eliminates the need for coding, compilation, and linking and constitutes the necessary step towards creating user interactive software on personal computers for power system studies. The final product includes the modified EMTDC main module and is linked with the EMTDC libraries MAIN, UTIL, VALG, and SVG plus additional subroutines to facilitate the simulation description p...

Transient simulation of integrated AC/DC systems. I. Converter modeling and simulation

IEEE Transactions on Power Systems, 1988

ABSTRACT For pt.I see ibid., vol.3, no.1, p.166-72 (1988). A flexible and computationally efficie... more ABSTRACT For pt.I see ibid., vol.3, no.1, p.166-72 (1988). A flexible and computationally efficient method is presented for transient simulation of integrated AC/DC systems. The method is based on network topological concepts and utilizes the results presented in pt.I. A modular modeling approach is used that facilitates the application of the method to any AC/DC system configuration

A gradient-based algorithm for the state initialization of control systems

IEEE Transactions on Power Systems, 1991

ABSTRACT The authors present an efficient algorithm for the state variable initialization of the ... more ABSTRACT The authors present an efficient algorithm for the state variable initialization of the network and control system. This algorithm is suitable for slow transient studies in AC/DC systems. It uses gradient methods to update the integrator inputs. The network is solved by the load-flow and the control system by the Gauss-Seidel method. Following the simultaneous steady-state solutions of the combined network and control system, the initial values of the state variables describing the dynamics for each component are calculated. A computer program was developed on the basis of the proposed algorithm for the initialization of slow transient studies in AC/DC systems. Results from the initialization of a typical AC/DC system are given

Application independent interactive environment for power systems education

IEEE Transactions on Power Systems, 1991

The authors present an interactive software package for the simulation of power system stability ... more The authors present an interactive software package for the simulation of power system stability studies. The package is intended as a supplementary tool for the teaching of power system stability courses at the graduate level. The development of the package was done exclusively for IBM-PC and compatible computers. The hardware mainly requires VGA display and 640 kbyte of memory. Professional

Finite-Element Models for Open-Air Power Lines in Broadband PLC

IEEE Transactions on Power Delivery, 2006

ABSTRACT This paper describes the application of finite elements for the modeling and simulation ... more ABSTRACT This paper describes the application of finite elements for the modeling and simulation of overhead power-line structures in the high-frequency range, using existing computing tools and software. This paper treats specifically non-uniform wire arrangements common in overhead power networks, including line junctions, bends, neutral grounding, etc., which disturb the transmission of signals, especially at high frequencies, increasing reflections, radiation, and mode conversion. The proposed models could be used in applications associated with broadband communication over power lines providing a reliable representation for assessing the capability of the overhead network to carry high-frequency signals and estimate the resulting electromagnetic emissions

Development of a control scheme for a series-connected solid-state synchronous voltage source

IEEE Transactions on Power Delivery, 1996

ABSTRACT This paper addresses the problem of controlling and modulating the power flow of long tr... more ABSTRACT This paper addresses the problem of controlling and modulating the power flow of long transmission lines using a series-connected solid-state synchronous voltage source (SVS). The design of the various control functions of the SVS is presented along with EMTP simulation studies. The results from these studies demonstrate the effectiveness of the proposed approach in regulating the line power and, also, in providing power modulation that can enhance the dynamic and transient performance of the line

A 12-pulse static synchronous compensator for the distribution system employing the 3-level GTO-inverter

IEEE Transactions on Power Delivery, 1997

ABSTRACT The paper presents an advanced scheme for the shunt compensation of distribution systems... more ABSTRACT The paper presents an advanced scheme for the shunt compensation of distribution systems that can significantly improve the harmonic profile of power lines without increasing the system complexity and size. The scheme employs a transformerless arrangement of three-level GTO inverters that can generate a five-level output. A gate control is developed that fully utilizes the capabilities of this arrangement to provide twelve-pulse operation for the compensator. The proposed compensator can connect directly to the distribution grid without a transformer. The effectiveness and performance of the proposed compensator are tested through simulated studies on a 13.8 kV distribution system

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