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Grid-Connected Systems
Published in Mukund R. Patel, Omid Beik, Wind and Solar Power Systems, 2021
The link connecting a renewable power site with the area grid introduces an operating limit in two ways, the voltage regulation and the stability limit. In most cases, the link can be considered as an electrically short transmission line. The ground capacitance and the ground leakage resistance are generally negligible. The equivalent circuit of such a line, therefore, reduces to a series leakage impedance Z (Figure 16.8). Such an approximation is valid in lines up to 50 mi long. The line carries the renewable power to the grid or from the grid to the renewable site during local peak demand. There are two major effects of the transmission line impedance, one on the voltage regulation and the other on the maximum power transfer capability of the link, as discussed in the following text.
Transmission Line Time-Domain Analysis and Signal Integrity
Published in Bogdan M. Wilamowski, J. David Irwin, Fundamentals of Industrial Electronics, 2018
Edward Wheeler, Jianjian Song, David R. Voltmer
Understanding the characteristics of transmission lines is necessary where wave behaviors such as propagation, reflection, and interference are important factors. In the time domain, this can be quantified by comparing propagation time to rise or fall times of the signals propagating. Whenever propagation times are not much shorter than rise times, wave behavior can no longer be ignored. Consider the system shown in Figure 31.1. If the rise time (tr) associated with the source voltage is much longer than the propagation delay time (td) for the line connecting the source and load, then wave behavior is not important. In this case, all time variations are gradual compared to the propagation delay, and understanding transmission lines is not an important factor in understanding system behavior. These lines could simply be treated as nodes connecting the source and load. If the electrically short line’s resistance, capacitance, or inductance were important, then the lines could be represented in a lumped element model. On the other hand, at higher speeds, where tt is not much longer than td, reflections can play an important role. The source could see waves that have been reflected from the load and which could be re-reflected from the source, and so on. For this case, wave behavior is clearly important and a sound understanding of transmission lines becomes essential to understanding how the system works.
Low-Power and Low-Voltage Communication for SoCs
Published in Christian Piguet, Low-Power CMOS Circuits, 2018
We may then conclude the transmission line case as follows (assuming a random sequence of binary data and a driver with output impedance Z0). For transmission lines terminated by Z0 in the far end, the power consumption is simply the same as that of a resistor of value 2Z0 (driver resistance in series with load resistance). For an open transmission line, we have two cases: for the electrically short line, the power consumption is the same as of a capacitor of value Cw. For an electrically long line, it is half of the terminated line case with the same supply voltage (note, however, that voltage swing in the terminated case is Vdd/2, and, in the open case, is Vdd) (see Figure 14.4).
Effect of initial stresses on the surface wave propagation in highly anisotropic piezoelectric composite media
Published in Waves in Random and Complex Media, 2023
Dharmendra Kumar, Santimoy Kundu
Figure 3(a) and 3(b) delineate the impact of angles of inclination and initial stress on the phase velocity of Rayleigh wave in a piezoelectric-orthotropic composite structure for electrically open- and short-circuit cases, respectively. It can be noticed from the figures that the phase velocity of the Rayleigh wave decreases initially with an increase in the magnitude of the angle of inclination and after a certain wave number, the nature of curves get reversed for electrically open circuit case. However, the phase velocity increases with an increase in the angle of inclination and after a specific wave number, it decreases significantly for higher values of wave number in the electrically short-circuit case. Moreover, the presence of initial stress decreases the phase velocity of the Rayleigh wave more for the electrically open circuit case as compared to the electrically short-circuit case along all the incidence angles.
Modeling the Interaction of Electrodynamic Fields to Circuit Elements
Published in IETE Journal of Education, 2018
If the height of a transmission line is electrically short compared to the shortest wavelength of the excitation field [2], then a long transmission line may be broken into electrically short sections. Figure 1 shows a representative model (per unit length ) based on the telegraph equations in prior work [3–6]. The voltage and current sources (per unit length) model the coupling of the excitation transient electromagnetic fields. The series voltage source is a function of the excitation magnetic field normal to the transmission line and the parallel current source is a function of the excitation electric field in the direction of the height of the transmission line. Alternative transmission line coupling models are found in other work [7–9].
Acoustic surface wave dispersion with strain gradient elasticity and micro-inertia effect in lossy polymer-coated piezoelectric structure
Published in Waves in Random and Complex Media, 2022
Sanjeev A. Sahu, Mahargha Biswas
It is evident from Figures 5(b) and 6(b) that attenuation curves get demoted by elevating the magnitude of . But likewise phase velocity curves, the impact of is minute for electrically short circuit case in comparison of open case. The attenuation curves of both case also manifest that in lower wave number region the impact of is insignificant.