J.L. Guardado

Morelia Institute of Technology · Department of Electrical and Electronic Engineering

This paper presents a new reliability analysis method for High Voltage Direct Current (HVDC) transmission systems based on the Matrix-Based System Reliability method. The proposed method can compute the failure probability of HVDC transmission systems by use of efficient matrix-based procedures. Unlike conventional system reliability methods whose...

Earth impedances of aerial power-lines usually are calculated through methods and approximate formulas based on the Carson integral. This paper presents a methodology to evaluate their accuracy and to serve as aid to select an appropriate method or formula in specific applications. Reference values for the Carson integral are first obtained through...

The simultaneous solution of circuit and field equations is often required in the analysis of magnetic devices. Although schemes for the solution of this coupled problem have been proposed, the existing formulations are usually tied to specific time discretization or nonlinear iteration expressions and therefore lack generality. In this paper, a hi...

This paper describes an algorithm to detect, localize and classify fault events in overhead transmission lines compensated with a thyristor-controlled series capacitor (TCSC). During a fault event, a complex pattern of traveling wave reflections and refractions is generated at the point of fault inception. The proposed algorithm uses the discrete w...

This article proposes a new evolutionary algorithm for power distribution system reconfiguration considering a multi-objective optimization approach. The proposed algorithm is based on the use of local searches distributed strategically along the Pareto front. The combination of local searches with elitism improves the convergence speed, diversity,...

An improved scheme for coupling electromagnetic transients programs with finite element magneto-dynamic field programs is presented. The proposed scheme uses the compensation approach to build up a strong coupling between domains, with no time delay. This permits to fully take into account the spatial field distribution in the magnetic device as we...

An analytical model for the assessment of cable ampacity due to non-uniform underground temperature distribution is presented. The uneven underground temperature is usually caused by a non-uniform surface heating (e.g., a street or parking crossing, etc.), which is extended for certain length along the cable installation and in depth. The undergrou...

In this paper, a differential relay model (87T) is developed in the Alternative Transient Program for power transformer protection. The relay model uses an anti-aliasing filter and the Discrete Fourier Transform to calculate the relay operation and restriction currents. The relay model includes second, fourth and fifth harmonic restriction for bloc...

1 Abstract—This paper proposes a fault detection and localization method for power transmission lines with a Static Synchronous Series Compensator (SSSC). The algorithm is based on applying a modal transformation to the current and voltage signals sampled at high frequencies. Then, the wavelet transform is used for calculating the current and volta...

Electrical utilities have the problem of applying complex mathematical models for maintenance optimization of power equipment. This is because the models presented in the literature lack the simplicity desired to carry out evaluations, and some others require a great number of input data, which may not be easily available. In order to overcome thes...

Recent developments in synchronized voltage phasor measurements has made wide area protection and control schemes possible. Recently, wide area disturbances has forced utilities to design protection and control schemes to protect the power system from angular, voltage and frequency instabilities, in order to avoid a complete or partial blackout. A...

Phasor measurement units (PMUs) are the key components in modern wide-area monitoring, protection, and control systems. This paper addresses the development of a PMU model in the Alternative Transients Program/Electromagnetic Transients Program. The performance of the proposed PMU model is assessed during normal and abnormal operating conditions us...

An analytical optimization method for preventive maintenance (PM) policy with minimal repair at failure, periodic maintenance, and replacement is proposed for systems with historical failure time data influenced by a current PM policy. The method includes a new imperfect PM model based on Weibull distribution and incorporates the current maintenanc...

Network reconfiguration is an alternative to reduce power losses and optimize the operation of power distribution systems. In this paper, an encoding scheme for evolutionary algorithms is proposed in order to search efficiently for the Pareto-optimal solutions during the reconfiguration of power distribution systems considering multiobjective optim...

A high impedance fault (HIF) normally occurs when an overhead power line physically breaks and falls to the ground. Such faults are difficult to detect because they often draw small currents which cannot be detected by conventional overcurrent protection. Furthermore, an electric arc accompanies HIFs, resulting in fire hazard, damage to electrical...

In this paper, a new approach for modeling grounding grids excited by lightning currents is proposed. The model is based on considering each set of parallel conductors in the grounding grid as a multiconductor transmission line. Electrical parameters are calculated and modal analysis is used in order to obtain a two port network representation for...

This paper describes a new relaying algorithm for the protection of transmission lines with a Thyristor Controlled Series Compensator (TCSC). The algorithm is based on the pattern of traveling waves generated during a fault event. Several tools like modal analysis, the discrete wavelet transform and a probabilistic neural network trained to work wi...

This paper presents the modeling and implementation of a traveling wave relay for transmission line protection at Extra High Voltage. The protection scheme is compounded of two algorithms; the first of them is a type D which is synchronization via GPS satellite and is used as the primary relay. The second algorithm uses a single end measurement and...

A high-impedance fault is generated when an overhead power line physically breaks and falls to the ground. Such faults are difficult to detect and locate in electric power systems because of the small currents and voltage drops involved, which cannot be detected by conventional protection. Furthermore, arcing accompanies high-impedance faults, resu...

This paper describes a genetic algorithm developed for power distribution system reconfiguration with minimal losses. The reconfiguration problem consists in identifying a new network topology with minimal power losses, while all the electrical system constraints are satisfied like radial topology, lines and substations power flow below capacity li...

A new method for calculating the parameters of electric arc models for power circuit breaker is developed. The methodology consists in the optimization of the theoretical arc voltage curve, as a function of a set of parameters, with respect to experimental data. Since the solution of the equation for the electric arc model cannot be obtained in gen...

This article deals with the design, construction, and testing of a new control system for a static VAr compensator. The new control system is based on monitoring reactive power, which is used as the only feedback variable for a digitally controlled oscillator. In addition to synchronizing the static VAr compensator with the AC system, the digitally...

Magnetic devices such as transformers and rotating electrical machines are key components of modern power systems and the simulation of transient events involving them is fundamental. In this paper, a method for strongly coupling a power systems transients program with a finite element field solver is proposed, which eliminates the time step delay...

The design, construction and test of a new hybrid control for static compensators (STATCOM) is presented. It uses a digitally controlled oscillator (DCO) to synchronize the STATCOM with an AC system that may exhibit frequency variations. The control also schedules the firing of the converter valves in order to achieve the reactive power compensatio...

The design, construction and test of a new hybrid control for static compensators (STATCOM) is presented. It uses a digitally controlled oscillator (DCO) to synchronize the STATCOM with an AC system that may exhibit frequency variations. The control also schedules the firing of the converter valves in order to achieve the reactive power compensatio...

High currents leaked to earth, leads to an electric field, which can be capable of breaking down the dielectric strength of the soil. When this happens, the ionization phenomena takes place, which reduce the grounding system impedance and modify its performance. In this paper, a computational model for transient performance of grounding systems is...

A new set of formulas for calculating the self and mutual impedances of coils on straight and closed laminated ferromagnetic cores of circular cross-section has been derived. The obtained formulas generalize the well-known formulas for impedances of coils on homogeneous ferromagnetic cores, for the case of laminated cores, and improve the previousl...

Coupled circuit-field solutions provide a powerful tool to simulate the detailed behavior of electrical machines and other magnetic devices operating as part of a larger system. The coupling of both domains can be made inside a single analysis tool, or it may be attempted by combining two separate-domain programs, thus taking advantage of the indiv...

This paper describes a genetic algorithm (GA) developed for the reconfiguration of radial distribution systems. The reconfiguration is treated as an optimization problem of combinatory nature, where the aim is to obtain a configuration with minimal power losses, iterations and also with some distribution system restrictions. The initial population...

The differential inductance and flux linkage positional derivative are important parameters in the analysis and simulation of electrical machines where saturation is nonnegligible. A new method for the computation of these quantities for devices with an arbitrary number of windings is presented. The method is based on the determination of the sensi...

An electro–thermal model for a Zinc Oxide (ZnO) surge arrester under contamination tests is presented. The model is based in three sub–models: electrical, thermal and contamination, which interact in order to obtain the surge arrester performance under contamination tests. The electrical model is obtained from measurements and is based on a capacit...

An electro-thermal model for a Zinc Oxide (ZnO) surge arrester under contamination tests is presented. The model is based in three sub-models: electrical, thermal and contamination, which interact in order to obtain the surge arrester performance under contamination tests. The electrical model is obtained from measurements and is based on a capacit...

Multi-rate methods are under development for performing time-domain simulation of EMTs in large power systems. It is affirmed in this paper that TD EMT analysis can benefit from complementary analysis in the frequency domain. It is proposed, in addition, that an important trend for frequency domain EMT analysis is the development of multi-rate meth...

A new method of calculating parameters of electric arc model of SF₆ power circuit breaker is proposed. The methodology consists in the optimization of a theoretical function with respect to a group of parameters of model in order to achieve a better approximation to a set of experimental data. The theoretical function is an asymptotic so...

In this work, a computer model for calculating surge distribution in power transformer windings is presented. The model is based on multiconductor transmission line theory, considering each disk coil as the basic element for the analysis. The electric parameters R, L, C and G are calculated by using conventional formulations. The electrical paramet...

This paper describes a phase-domain frequency domain technique to the harmonic analysis of a three-phase AC/DC system. The methodology is based on the harmonic multi-port network concept, expressed in terms of an ABCD parameter matrix which links voltage and current harmonics of different orders on both sides of the converter. Since the commutation...

In this work a computer model for calculating surge distribution in transformer windings is presented. The transformer model is developed using transmission line theory. The capacitance, inductance, resistance and conductance are calculated with simple formulations. The electrical parameters are used for calculating modal parameters in order to rep...

Series compensation of long transmission lines is widely used in electrical power systems in order to reduce losses and increase the transmission line capacity. However, for certain values of compensation, the series connected capacitors interact with the mechanical elements of the turbine-generator group leading to sub-synchronous resonance, which...

In this paper, a methodology for calculating the setting impedance of zones 2 and 3 of distance relays is presented, The aim is to reduce protection coordination problems during fault occurrence and changes in the network configuration. The proposed method is based on the impedance seen by the distance relay when faults are simulated on adjacent no...

This is an introductory paper on z-transform-based methods for electromagnetic transient simulations of power systems. Since the theory of the z-transform was originally developed for the analysis of time series data defined at equidistant time steps, simulation models developed using z-transforms can readily be used in electromagnetic transient si...

Frequency domain methods are invaluable as complements to the time domain ones to analyze electromagnetic transients in power systems. This paper presents an overview of those frequency domain methods most commonly used in this analysis; namely, the Fourier transform, the Laplace transform and the Z-transform. These three methods are presented here...

In this paper, finite element (FE) field models for the calculation of resistance, inductance and capacitance in high voltage machine windings are developed. The models take into account frequency-dependent phenomena such as the skin and proximity effects and the magnetic flux penetration into the iron core. The accuracy of the electrical parameter...

This paper explores an asymptotic approach to the solution of a non-linear transmission line model. The model is based on a set of non-linear partial differential equations without analytical solution. The perturbations method is used to reduce the system of non-linear equations to a single non-linear partial differential equation, the modified Kor...

This article describes the design, construction and characterization of a digital meter of electric energy based on a microcontroller. The meter carries out the calculation of the demand for the kWh consumption, being based on a staggered rate of domestic type of the Federal Commission of Electricity (C.F.E.) in Mexico. The prototype also presents...

In this work, a new model for the simulation of fast transients on nonuniform multiconductor transmission lines is presented. The proposed model is based on the method of characteristics of partial differential equations theory and includes a variation of the electrical parameters with the distance and frequency. In addition, Norton circuits for th...

In this paper, terminal models for high voltage machine windings are developed. The models are useful for simulating transient overvoltages due to switching operations on industrial installations. The models are based on network synthesis of the winding terminal impedance. The process of synthesis is carried out by taking into account the winding r...

This paper describes a computer model for calculating the surge propagation in the winding of electrical machines. The model considers the winding as a combination of a multiconductor transmission line and a network of lumped parameters. The frequency dependence of the winding electrical parameters is calculated and incorporated into the analysis b...

Time domain terminal models for high voltage induction motor windings are developed for simulating transient overvoltages due to switching operations in industrial installations. The models are based on the network synthesis of the terminal impedance for short circuit and open circuit conditions of the winding. The process of synthesis is carried o...

This paper introduces a new tool which promptly and effectively determines the impedance setting for Zone I and II of distance relays. From the electrical network topology the algorithm determines the primary-backup relay pairs. Then, a short-circuit study is carried out as a previous step to finally calculate the relay adjustments and coordination...

This paper describes a method for the analysis of electromagnetic transients in multiphase transmission networks using the Numerical Laplace Transform. The proposed procedure is based on the superposition principle and is applied to switching and non-linear elements modeling. Switching operations are modeled as initial condition problems by means o...

A computer model that describes the dynamic arc behavior in the high- and low-current regions before current zero is proposed. The model divides the current and voltage waveform in two regions. A differential equation for both regions which unifies current and voltage time derivatives is obtained by means of a generalized function method. The compu...

A method for coupling electromagnetic transients programs and finite element field solvers is introduced. The field model takes into account the detailed structure of the magnetic device, including saturation effects, and provides a set of parameters in the form of an inductance matrix, which is then communicated to the transients program. The para...

Nonlinear oscillations in the molecular dimer, composed of two monomers, are investigated, considering an arbitrary number of excitons in the system. The bosonic operators are used to describe the exciton dynamics, that leads to value of the radius of a Bloch sphere that differs from known results. The Hamiltonian of the system is used to reduce th...

The quantum distribution function is derived to reach an accordance with quantum hydrodynamics and to conserve quantum properties of the system. This distribution function, when calculating statistical averages, leads to correct local values of the fundamental physical quantities; and the local conservation laws of the microscopic quantum hydrodyna...

A comprehensive analysis of Pollaczek's integral is presented in this paper. It reveals the difficulties found when attempting its numerical solution. This analysis further provides a strategy to avoid these difficulties. A numerical algorithm is then proposed and implemented. Solutions to Pollaczek's integral are provided in graphic form for a bro...

We consider the initial-boundary-value problem on the half-line for the Kortewegde Vries equation ut + uux + uxxx = 0, t > 0, x > 0,} u(x, 0) = u0(x), x > 0, u(0, t) = 0, t > 0. We prove that if the initial data u0 ∈ H10,2 ∩ H20,3/2 and the norm ∥u 0∥H10,2 + ∥u0∥H20,3/2 are sufficiently small, where Hps,k = {f ∈ L 2; ∥f∥Hps,k = ∥〈x〉 k〈i∂x〉sf∥Lp < ∞...

This work describes a method for the analysis of electromagnetic transients in multiphase transmission networks using the numerical Laplace transform. The proposed procedure is based on the superposition principle and is applied to switching and nonlinear elements modeling. Switching operations are modeled as initial condition problems by means of...

This paper focuses on the representation of tall metallic structures, such as power line towers, by means of vertical transmission line segments. Some of the most common tower models are tested here. The differences between the single vertical line models and the vertical multiconductor ones are demonstrated through the comparison with a field expe...

Finite element models are developed for the calculation of the coil resistance, inductance and capacitance in rotating machine windings. Resistance and inductance are calculated by analyzing the time harmonic fields in the machine, taking into account skin and proximity effects as well as the magnetic flux penetration into the iron core. The capaci...

A coupled quasiparticle-oscillator system is considered for an arbitrary number of excitons. The exciton dynamics is described in terms of the second quantization (i.e. by means the bosonic operators). As a consequence a radius of a Bloch sphere is obtained different to the previous results. Some integrals of motion are obtained that allowed to red...

An analysis of Pollaczek's integral is presented in this paper. It reveals the difficulties found when attempting its numerical solution. The analysis provided here further indicates a strategy to avoid these difficulties. A numerical algorithm is then described and implemented. Solutions to Pollaczek's integral are provided in graphical form for a...

This paper describes a method for the analysis and simulation of electromagnetic transients in underground power transmission and submarine cables. This method uses the frequency domain technique known as the numerical Laplace transform [Int. J. Electl Engng Educ., 15 (1978) 247]. This method can be used, as a principal analysis tool or as a backup...

This paper presents a comparative study of neural network (NN) efficiency for the detection of incipient faults in power transformers. The NN was trained according to five diagnosis criteria commonly used for dissolved gas analysis (DGA) in transformer insulating oil. These criteria are Doernenburg, modified Rogers, Rogers, IEC and CSUS. Once train...

This paper presents a comparative study of neural network (NN) efficiency for the detection of incipient faults in power transformers. The NN was trained according to five diagnosis criteria commonly used for dissolved gas analysis (DGA) in transformer insulating oil. These criteria are Doemenburg, modified Rogers, Rogers, IEC, and CSUS. Once train...

In order to take into account the frequency dependence of transmission line parameters, the propagation equations with transient parameters have to be solved. In this work these equations are integrated by means of the method of characteristics and a convolution procedure using synthesized rational functions. The effects of corona are included usin...

This paper addresses the problem of transient overvoltages in electrical motors during sequential pole closure in industrial installations. A computer model that includes the circuit breaker, high-voltage cable and electrical motor is proposed. Multiconductor transmission line theory and modal analysis are applied to the components and the piecewis...

The method of characteristics of partial differential equations (PDEs) theory has been previously applied to the analysis of transients on transmission lines with corona. It is proposed here that this method be applied also to the analysis of nonuniform lines. The advantages of doing this are illustrated by analyzing the nonuniformities caused by t...

This paper addresses the problem of transient overvoltages in electrical machines during sequential pole closure on industrial installations. A three-phase computer model that includes the circuit breaker, high-voltage cable and electrical machine is proposed. Multiconductor transmission line theory and modal analysis are applied to the components...

This paper describes a computer model for surge distribution studies in the windings of electrical machines. The computer model takes the coil as the basis for the analysis and uses multiconductor transmission line theory to obtain the transference matrix for the winding. Several practical formulations based on machine design characteristics are us...

This paper describes a multiconductor transmission line approach for calculating the machine winding electrical parameters for switching transient studies. The technique is based upon the solution of the one dimension diffusion equation in the slot of electrical machines. The coil electrical parameters are calculated considering both the magnetic f...

This paper describes a technique for calculating interturn voltages in machine windings during transient conditions. The technique is based on the measurement of switching transients at the machine terminals and computer simulation of the surge travelling through the winding. The machine winding is treated as a multiconductor transmission line and...

The authors identify the coil parameters that are of importance, when assessing interturn voltages produced by steep-fronted transients. The studies are based on a multiconductor transmission line computer model of a machine winding energized by a simple ramp function. Variations in interturn voltages produced by changes in insulation thickness, in...

Interturn voltages produced in the line-end coils of machine windings when steep-fronted prestriking transients reach the winding are usually predicted by injecting a simple ramp-function voltage wave into a computer simulation of the winding. In practice, steep-fronted prestriking transients have complex waveforms, and it is possible that a simple...

Not Available

A computer model for predicting the distribution of steep-fronted surges in the line-end coils of machine windings is described. The model uses certain aspects of previous models combined to achieve simplification of solution while retaining accuracy. The solution technique is based on multiconductor transmission line theory and modal analysis. Par...

In this work, a computer model for calculating surge distribution in power transformer windings is presented. The model is based on multiconductor transmission line theory, considering each disk coil as the basic element for the analysis. The electric parameters R, L, C and G are calculated by using conventional formulations. The electrical paramet...

This paper describes a computer model for calculating the surge propagation in the winding of electrical machines. The model considers the winding as a combination of a multiconductor transmission line and a network of lumped parameters. The frequency dependence of the winding electrical parameters are calculated and incorporated into the analysis...

In this paper a computer model to analyze the transient performance of grounding systems is presented. The model is based on considering each section of parallel conductors in the grounding system as a multiconductor transmission line. Modal analysis and two port network theory are used to obtain the grounding system response to an excitation in th...