.net barcode printing Transient Overvoltages Transient Overvoltages 119 in Software

Encode PDF-417 2d barcode in Software Transient Overvoltages Transient Overvoltages 119

Transient Overvoltages Transient Overvoltages 119
PDF417 Creation In None
Using Barcode printer for Software Control to generate, create PDF 417 image in Software applications.
Recognize PDF-417 2d Barcode In None
Using Barcode reader for Software Control to read, scan read, scan image in Software applications.
Figure 47 Coupling of impulses through the interwinding capacitance of transformers
PDF-417 2d Barcode Generation In C#.NET
Using Barcode drawer for .NET Control to generate, create PDF-417 2d barcode image in Visual Studio .NET applications.
Encode PDF417 In Visual Studio .NET
Using Barcode encoder for ASP.NET Control to generate, create PDF-417 2d barcode image in ASP.NET applications.
distribution system This is likely due not to capacitive coupling through the service transformer but to conduction around the transformer through the grounding systems as shown in Fig 48 This is a particular problem if the load system offers a better ground and much of the surge current flows through conductors in the load facility on its way to ground The chief power quality problems with lightning stroke currents entering the ground system are 1 They raise the potential of the local ground above other grounds in the vicinity by several kilovolts Sensitive electronic equipment that is connected between two ground references, such as a computer connected to the telephone system through a modem, can fail when subjected to the lightning surge voltages 2 They induce high voltages in phase conductors as they pass through cables on the way to a better ground The problems are related to the so-called low-side surge problem that is described in Sec 453 Ideas about lightning are changing with recent research10 Lightning causes more flashovers of utility lines than previously thought Evidence is also mounting that lightning stroke current wavefronts are faster than previously thought and that multiple strikes appear to be the norm rather than the exception Durations of some strokes may also be longer than reported by earlier researchers These findings may help explain failures of lightning arresters that were thought to have adequate capacity to handle large lightning strokes
PDF-417 2d Barcode Generation In Visual Studio .NET
Using Barcode drawer for .NET Control to generate, create PDF 417 image in Visual Studio .NET applications.
PDF-417 2d Barcode Generation In Visual Basic .NET
Using Barcode maker for VS .NET Control to generate, create PDF 417 image in .NET applications.
Downloaded from Digital Engineering Library @ McGraw-Hill (wwwdigitalengineeringlibrarycom) Copyright 2004 The McGraw-Hill Companies All rights reserved Any use is subject to the Terms of Use as given at the website
Code 128 Code Set C Creation In None
Using Barcode encoder for Software Control to generate, create Code 128B image in Software applications.
Encode DataMatrix In None
Using Barcode drawer for Software Control to generate, create Data Matrix 2d barcode image in Software applications.
Transient Overvoltages 120 Four
Make UPC-A Supplement 2 In None
Using Barcode maker for Software Control to generate, create UPC-A Supplement 2 image in Software applications.
Code 3/9 Generator In None
Using Barcode printer for Software Control to generate, create Code-39 image in Software applications.
PRIMARY ARRESTER
Encoding UCC-128 In None
Using Barcode generator for Software Control to generate, create EAN / UCC - 14 image in Software applications.
Bar Code Printer In None
Using Barcode creator for Software Control to generate, create barcode image in Software applications.
OTHER GROUND
Generating Postnet In None
Using Barcode generation for Software Control to generate, create Delivery Point Barcode (DPBC) image in Software applications.
Data Matrix ECC200 Encoder In Java
Using Barcode generation for Android Control to generate, create Data Matrix 2d barcode image in Android applications.
TRANSFORMER GROUND
GTIN - 128 Maker In Objective-C
Using Barcode generation for iPhone Control to generate, create GTIN - 128 image in iPhone applications.
Code 39 Encoder In Objective-C
Using Barcode generation for iPhone Control to generate, create Code 3/9 image in iPhone applications.
Lightning impulse bypassing the service transformer through ground connections
Painting UPC - 13 In Java
Using Barcode generator for Java Control to generate, create GS1 - 13 image in Java applications.
Code 39 Encoder In VB.NET
Using Barcode generator for Visual Studio .NET Control to generate, create ANSI/AIM Code 39 image in VS .NET applications.
414 Ferroresonance
ANSI/AIM Code 128 Maker In C#.NET
Using Barcode maker for VS .NET Control to generate, create Code 128A image in .NET framework applications.
EAN 13 Generator In Java
Using Barcode creation for Android Control to generate, create GS1 - 13 image in Android applications.
The term ferroresonance refers to a special kind of resonance that involves capacitance and iron-core inductance The most common condition in which it causes disturbances is when the magnetizing impedance of a transformer is placed in series with a system capacitor This happens when there is an open-phase conductor Under controlled conditions, ferroresonance can be exploited for useful purpose such as in a constant-voltage transformer (see Chap 3) Ferroresonance is different than resonance in linear system elements In linear systems, resonance results in high sinusoidal voltages and currents of the resonant frequency Linear-system resonance is the phenomenon behind the magnification of harmonics in power systems (see Chaps 5 and 6) Ferroresonance can also result in high voltages and currents, but the resulting waveforms are usually irregular and chaotic in shape The concept of ferroresonance can be explained in terms of linear-system resonance as follows Consider a simple series RLC circuit as shown in Fig 49 Neglecting the resistance R for the moment, the current flowing in the circuit can be expressed as follows: I where E XL XC driving voltage reactance of L reactance of C E j (XL |XC|)
When XL |XC|, a series-resonant circuit is formed, and the equation yields an infinitely large current that in reality would be limited by R An alternate solution to the series RLC circuit can be obtained by writing two equations defining the voltage across the inductor, ie,
Downloaded from Digital Engineering Library @ McGraw-Hill (wwwdigitalengineeringlibrarycom) Copyright 2004 The McGraw-Hill Companies All rights reserved Any use is subject to the Terms of Use as given at the website
Transient Overvoltages Transient Overvoltages 121
XL I E XC
Simple series RLC circuit
jXLI E j|XC|I
where v is a voltage variable Figure 410 shows the graphical solution of these two equations for two different reactances, XL and XL XL represents the series-resonant condition The intersection point between the capacitive and inductive lines gives the voltage across inductor EL The voltage across capacitor EC is determined as shown in Fig 410 At resonance, the two lines will intersect at infinitely large voltage and current since the |XC| line is parallel to the XL line Now, let us assume that the inductive element in the circuit has a nonlinear reactance characteristic like that found in transformer magnetizing reactance Figure 411 illustrates the graphical solution of the equations following the methodology just presented for linear circuits While the analogy cannot be made perfectly, the diagram is useful to help understand ferroresonance phenomena It is obvious that there may be as many as three intersections between the capacitive reactance line and the inductive reactance curve Intersection 2 is an unstable solution, and this operating point gives rise to some of the chaotic behavior of ferroresonance Intersections 1 and 3 are stable and will exist in the steady state Intersection 3 results in high voltages and high currents Figures 412 and 413 show examples of ferroresonant voltages that can result from this simple series circuit The same inductive characteristic was assumed for each case The capacitance was varied to achieve a different operating point after an initial transient that pushes the system into resonance The unstable case yields voltages in excess of 40 pu, while the stable case settles in at voltages slightly over 20 pu Either condition can impose excessive duty on power system elements and load equipment For a small capacitance, the |XC| line is very steep, resulting in an intersection point on the third quadrant only This can yield a range of voltages from less than 10 pu to voltages like those shown in Fig 413
Downloaded from Digital Engineering Library @ McGraw-Hill (wwwdigitalengineeringlibrarycom) Copyright 2004 The McGraw-Hill Companies All rights reserved Any use is subject to the Terms of Use as given at the website
Copyright © OnBarcode.com . All rights reserved.