Characteristic of Electromagnetic Noise Based on the Theory of Multiconductor Communication Line

2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Yibo Ding ◽  
Kaiyan Zhang ◽  
Shishan Wang ◽  
Jian Guo
Keyword(s):  
Transmission Line ◽  
Transmission Lines ◽  
High Frequency ◽  
Transfer Functions ◽  
Communication Line ◽  
Electrical System ◽  
Electromagnetic Noise ◽  
Electrical Length ◽  
Voltage Loss ◽  
Small Voltage

Electromagnetic noise has serious influence on the performance of electrical system. In addition, while multiconductor cable harnesses play an important role in transmitting electromagnetic energy or signal between devices of electrical system, they are also the major path to transmit electromagnetic noise. Crosstalk, as typical electromagnetic noise within multi-conductor cable harnesses, is an important factor which affects the efficiency of transmission. In this paper, the n+1 transmission lines (n=2, n>2) are taken as the object of research. Based on the theory of Multi-conductor Transmission Line (MTL), the transmission of electromagnetic noise in transmission line is studied, including noise of generating line (called G-line) and line receiving interference (called R-line), the latter called crosstalk. Transfer functions of electromagnetic noise of G-line and R-line are simulated using FEKO (FEldberechnung bei Korpern mit beliebiger Oberflache). Two transfer functions are obtained to investigate the severity of noise of G-line and R-line. The characteristics of the parameters are also studied. Simulation results indicate that transfer functions have tight relationship with the electrical length. When the electrical length is small, voltage loss of interference line along the transmission line is relatively small, so is the far-end crosstalk; however, when the electrical length is large, voltage loss and the far-end crosstalk is larger, and resonances at high frequency. Keywords: Electromagnetic noise; FEKO; electrical length;

scholarly journals Currents in Line Conductors due to an Electron Avalanche

2021 ◽  
Author(s):  
Debasish Nath ◽  
Udaya Kumar
Keyword(s):  
Transmission Line ◽  
Transmission Lines ◽  
Basic Mechanism ◽  
Background Field ◽  
Modern World ◽  
Experimental Investigations ◽  
Electromagnetic Noise ◽  
Overhead Lines ◽  
Tem Mode ◽  
Induced Currents

<p>Transfer of bulk electric power required in the modern world can be realized only through EHV and UHV transmission lines. The scenario is dominated by overhead lines in which electromagnetic noise generated by corona is an important concern. Corona induced currents propagate along line conductors producing electromagnetic noise, which is essential to be quantified. In literature, large amount of work is based on experimental investigations which considers only limited frequency ranges and is not applicable to new line configurations. A set of semi-analytical methods have also been proposed, which employ the transmission line model for analysis. However, quasi-TEM mode of propagation inherently assumed by them has been questioned. Moreover, the corona current is modeled as shunt source without relating to the mechanism of induction due to corona. The present work aims to investigate the basic mechanism of current induction using an isolated avalanche developing under space charge modulated background field. The corresponding induced currents are quantified and the structure of the electric and magnetic fields is extracted. The basic issue with the long transmission line modelling is amply demonstrated. Even though single avalanche, being the basic process building corona is considered, general inferences can be drawn regarding corona on lines.</p>

Short circuits currents comparison of 6 (10) kV and 20 kV.

2020 ◽  
Vol 14 (1) ◽  
pp. 21-26
Author(s):  
S. SKRYPNYK ◽  
◽  
A. SHEINA ◽  
Keyword(s):  
Power System ◽  
Transmission Line ◽  
Transmission Lines ◽  
Power Supply ◽  
Short Circuit ◽  
Electric Arc ◽  
Electrical System ◽  
Three Phase ◽  
Short Circuits ◽  
Short Circuit Currents

Most failures in electrical installations are caused by short circuits (short circuits), which occur as a result of a failure in the electrical strength of the insulation of the conductive parts. A short circuit is an electrical connection of two points of an electric circuit with different values of potential, which is not provided by the design of the device, which interferes with its normal operation. Short circuits may result from a failure of the insulation of the current-carrying elements or the mechanical contact of the non- insulated elements. Also called a short circuit is a condition where the load resistance is less than the internal resistance of the power source. The reasons for such violations are various: aging of insulation, breakages of wires of overhead transmission lines, mechanical damages of isolation of cable lines at ground works, lightning strikes in the transmission line and others. Most often, short-circuits occur through transient resistance, such as through the resistance of an electric arc that occurs at the point of damage to the insulation. Sometimes there are metallic short circuits in which the resistance of the electric arc is very small. The study of short circuits in the power grid is a major step in the design of modern electrical networks. The research is conducted using computer software, first by modeling the system and then simulating errors. A malfunction usually leads to an increase in the current flowing in the lines, and failure to provide reliable protection can result in damage to the power unit. Thus, short-circuit calculations are the primary consideration when designing, upgrading, or expanding a power system. The three-phase short circuit is the least likely. However, in many cases, the three-phase short circuit is associated with the most severe consequences, as it causes the highest power imbalances on the shafts of the generators. The study of transients begins with the mode of three-phase closure due to its relative simplicity in comparison with other types of asymmetry. In most cases, the analysis and calculation of the transient regime of the electrical system involves the preparation of a calculated scheme of substitution, in which the parameters of its elements are determined in named or relative units. The electrical substitution circuitry is used to further study the transients in the power system. The definition of electrical and electromagnetic quantities in relative units is widely used in the theory of electric machines. This is because it significantly simplifies the theoretical calculations and gives the results a generalized view in the practical calculations of currents and residual voltages at the short circuit. By the relative value of any value is understood as its relation to another value of the same name, taken as the base. So, before presenting any quantities in relative units, we need to choose the basic units. In the electrical system with increased voltages, the overall load capacity of the network increases, which in turn makes it possible to supply high-quality electrical energy over a greater distance. In the process of comparing the type of transmission lines, it should be noted that the advantages of the cable transmission line. According to the results of the calculation of short-circuit currents, it can be concluded that in networks with a larger line cross-section and a higher voltage, the short-circuit currents are larger. Thus, during the transition of the electric networks to the higher voltage class of 20 kV, the currents of the KZ increased by 43% compared to the 6 kV electric network. This analysis shows that the importance of reliable power supply in the power supply system for high voltage classes must be high and have equipment to prevent emergencies. In the future, it is planned to develop a systematic calculation of short-circuit currents for a number of transmission lines and to conduct mathematical modeling in the system of applications for the study of transient processes at short circuits.

scholarly journals Analysis of electromagnetic fields in transmission line configurations associated with the electrical system

Athenea ◽  
2021 ◽  
Vol 2 (4) ◽  
pp. 31-37
Author(s):  
Adrian Beria ◽  
Juan Toledo
Keyword(s):  
Transmission Line ◽  
Electromagnetic Fields ◽  
Transmission Lines ◽  
Hydroelectric Plant ◽  
International Standards ◽  
Pablo Picasso ◽  
Electrical System ◽  
Cesar Vallejo ◽  
Transmission Towers ◽  
Ac Transmission

This work presents an analysis of the electromagnetic fields generated by the different configurations of transmission lines associated with the Venezuelan electrical system, with voltages 230, 400 and 765 kilo Volts, and the transmission towers that will be built at the Manuel Piar Hydroelectric Plant. - Tocoma. The theoretical aspects and technical foundations for the evaluation of the magnetic field in transmission lines are analyzed. The work was carried out at the CORPOELEC company in Venezuela. The criteria and technical regulations were observed to verify respect for the levels allowed by national and international standards, to which a person may be exposed. The results show the location areas of the transmission lines and their corresponding electromagnetic analysis. Keywords: Electromagnetic fields, transmission lines, transmission towers. References [1]EPRI AC Transmission Line Reference Book- 200 kV and Above, Third Edition. 2005. [2]"Interruptores de desconexión de aire de alto voltaje estándar nacional estadounidense Interruptores interruptores, interruptores de iniciación de fallas, interruptores de puesta a tierra, soportes de bus y accesorios Rangos de voltaje de control: programas de clasificaciones preferidas, pautas y especificaciones de construcción", en ANSI C37.32-1996 , vol., núm., págs. i-36, 1996, doi: 10.1109 / IEEESTD.1996.95627. [3]NEMA SG-6-1995, Nema sg 6 1995 tablas 32 1114 ilustración determina [Online], Available: https://www.coursehero.com/file/p5ngkj3/NEMA-SG-6-1995-Tables-32-1-114-Illustration-Determine-the-electrical/ [4]COVENIN 2238:2000. Radiaciones No Ionizantes. [Online], Available: http://www.sencamer.gob.ve/sencamer/normas/2238-00.pdf. [5]Codigo Nacional de Seguridad en Instalaciones de Suministro de Energia Electrica y de Comuninaciones, CODELETECTRA, Codigo de Seguridad Electrica. Espacios libres mínimos para partes activas. [6]ESP OIL Engineering Consultants, WorkShop International, "Diseno de subestaciones eléctricas", dictado por M.Sc Manuel Briceno, 2006. [7]F.Gonzalez-Longatt, Líneas De Transmisión. [Online], Available: https://fglongatt.org/OLD/Archivos/LT_1.html. [8]R. López Valverde. Historia del electromagnetismo. Ediciones IES, Pablo Picasso, 2001. [9]P. Muné, M. Hernández-Wolpez, A. Cruz-García y RJ Jardim. (2015). “Sobre la penetración y atrapamiento del flujo magnético en superconductores Bi-2223”. Rev. Cubana de Física. Vol. 32, no. 1 pp 53. [10]C. Furió y J. Guisasola. (2001). “La enseñanza del concepto de campo eléctrico basada en un modelo de aprendizaje como investigación orientada”. Rev. Enseñanza De Las Ciencias, 19 (2), pp.319-334. [11]D. Vásquez Gonzales. (2017) “Aplicación del método cadena crítica para la mejora en construcción de cimentaciones de torres autosoportadas – caso línea de transmisión 66kV, en Sayán, Lima” Tesis de grado. Universidad César vallejo. Perú. [12]J. Maxwell (1864). “Una teoría dinámica del campo electromagnético”. Rev. Sociedad de la realeza. Vol 155. [13]D. Strebkov. (2014) “Perspectivas de uso de tecnologías de nicola tesla en ingeniería de energía actualizada”. Rev.Light & Engineering. vol. 22 Edición 2, pp 4-14.

Transmission Line Modeling of Laminar Liquid Wave Propagation in Tapered Tubes

2019 ◽  
Vol 141 (10) ◽  
Author(s):  
Travis Wiens ◽  
Jeremy ven der Buhs
Keyword(s):  
Wave Propagation ◽  
Transmission Line ◽  
High Frequency ◽  
Transfer Functions ◽  
Domain Modeling ◽  
Transmission Line Model ◽  
Computationally Efficient ◽  
Transmission Line Modeling ◽  
Time Domain Modeling ◽  
Pipe Inlet

This paper presents an improved method of time-domain modeling of pressure wave propagation through liquid media in rigid tapered pipes. The method is based on the transmission line model (TLM), which uses linear transfer functions and delays to calculate the pressures and/or flows at the pipe inlet and outlet. This method is computationally efficient and allows for variable rate simulation. The proposed form of the model differs from previous TLM models in the literature, allowing it to accurately model both low and high frequency characteristics.

scholarly journals Currents in Line Conductors due to an Electron Avalanche

2021 ◽  
Author(s):  
Debasish Nath ◽  
Udaya Kumar
Keyword(s):  
Transmission Line ◽  
Transmission Lines ◽  
Basic Mechanism ◽  
Background Field ◽  
Modern World ◽  
Experimental Investigations ◽  
Electromagnetic Noise ◽  
Overhead Lines ◽  
Tem Mode ◽  
Induced Currents

<p>Transfer of bulk electric power required in the modern world can be realized only through EHV and UHV transmission lines. The scenario is dominated by overhead lines in which electromagnetic noise generated by corona is an important concern. Corona induced currents propagate along line conductors producing electromagnetic noise, which is essential to be quantified. In literature, large amount of work is based on experimental investigations which considers only limited frequency ranges and is not applicable to new line configurations. A set of semi-analytical methods have also been proposed, which employ the transmission line model for analysis. However, quasi-TEM mode of propagation inherently assumed by them has been questioned. Moreover, the corona current is modeled as shunt source without relating to the mechanism of induction due to corona. The present work aims to investigate the basic mechanism of current induction using an isolated avalanche developing under space charge modulated background field. The corresponding induced currents are quantified and the structure of the electric and magnetic fields is extracted. The basic issue with the long transmission line modelling is amply demonstrated. Even though single avalanche, being the basic process building corona is considered, general inferences can be drawn regarding corona on lines.</p>

BENEFITS OF TRANSMISSION LINE METAL-INSULATOR-METAL CAPACITORS IN MASS PRODUCTION OF RF CIRCUITS

2014 ◽  
Vol 2014 (1) ◽  
pp. 000838-000843
Author(s):  
Cenk ATALAN ◽  
Eyup TONGEL
Keyword(s):  
Thin Film ◽  
Transmission Line ◽  
Transmission Lines ◽  
High Frequency ◽  
Short Circuit ◽  
Microstrip Transmission Line ◽  
Metal Insulator ◽  
Coupling Capacitor ◽  
Metal Insulator Metal ◽  
Rf Microwave

Coupling capacitors or DC blocks are essential tuning elements in RF/microwave applications. Their role becomes imperative in cascade amplifiers to isolate drain voltages of preceding MMIC from the gate voltage of the following chip where both RF and DC signals are carried through the same line. The purpose of this study is to explain the benefits of a newly designed thin film coupling capacitor called as transmission line metal-insulator-metal capacitor (TL MIM Cap), which serves as a DC block capacitor in microwave circuits. This novel structure provides a unique solution, which cannot be achieved with traditional single layer ceramic capacitor (SLC) structure. It combines two discrete circuit elements into one: “Microstrip transmission line of required length and width” with a “serially attached coupling capacitor”. Thin film capacitive layers ranged from 0.5pF to 50pF, which are typically needed for microwave frequencies within 1–40 GHz, constructed and embedded into 50 Ohm impedance transmission lines in series. Substrates like quartz, glass, or alumina can be used to minimize losses and to achieve higher RF/microwave performance. We used copper traces as conductive layers for optimal conductivity. After manufacturing TL MIM Caps, we tested several capacitance values for 1pF, 5pF, 15pF and 30pF corresponding to a wide frequency range. The RF tests we performed showed that TL MIM Caps exhibited a minimum of 20dB return loss and a maximum of 0.3 dB insertion loss at 1–40GHz range. We also found our technique comes with some workmanship advantages in high frequency circuit assembly as follows: Traditional coupling capacitor attachment with silver epoxy on top of a microstrip transmission line is a manual operation, which requires well trained and experienced technicians. In contrast, using the TL MIM Caps in our high frequency hybrid modules, we found that the process caused errors were eliminated such as the micro short circuit effect caused by conductive epoxy. Therefore we improved yield in assembly stage of the circuits. In addition, improvements are observed in production processes such as less consumption of adhesives (epoxy), no technician failure caused wastes, elimination of extra curing process to attach capacitors, no short circuit inspection, rework, or re-cure operations to fix assembly errors. Last but not least, blocking capacitors are embedded into the microstrip transmission lines in TL MIM Caps. This ensures that having the lowest possible impedance since very short wire bond exists from the bond pad of the TL MIM Cap to the adjacent circuit element.

Composite right/left-handed transmission line with array of thermocouples for generating terahertz radiation

2020 ◽  
Vol 92 (2) ◽  
pp. 20502
Author(s):  
Behrokh Beiranvand ◽  
Alexander S. Sobolev ◽  
Anton V. Kudryashov
Keyword(s):  
Transmission Line ◽  
Terahertz Radiation ◽  
Transmission Lines ◽  
Software Package ◽  
Optical Pulses ◽  
Capacitively Coupled ◽  
Voltage Difference ◽  
Left Handed ◽  
Microwave Transmission ◽  
Commercial Software Package

We present a new concept of the thermoelectric structure that generates microwave and terahertz signals when illuminated by femtosecond optical pulses. The structure consists of a series array of capacitively coupled thermocouples. The array acts as a hybrid type microwave transmission line with anomalous dispersion and phase velocity higher than the velocity of light. This allows for adding up the responces from all the thermocouples in phase. The array is easily integrable with microstrip transmission lines. Dispersion curves obtained from both the lumped network scheme and numerical simulations are presented. The connection of the thermocouples is a composite right/left-handed transmission line, which can receive terahertz radiation from the transmission line ports. The radiation of the photon to the surface of the thermocouple structure causes a voltage difference with the bandwidth of terahertz. We examined a lossy composite right/left-handed transmission line to extract the circuit elements. The calculated properties of the design are extracted by employing commercial software package CST STUDIO SUITE.

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