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Ferroresonance Oscillations in Substations

with Inductive Voltage Transformers in Medium and High Voltage Systems

Ruthard Minkner, Joachim Schmid, Holger Däumling, Udo Prucker, Reinhold Bräunlich und Martin Hofstetter

Diese Publikation zitieren

Ruthard Minkner, Joachim Schmid, Holger Däumling, Udo Prucker, Reinhold Bräunlich, Martin Hofstetter, Ferroresonance Oscillations in Substations (2017), VDE Verlag, Berlin, ISBN: 9783800742509

Getrackt seit 05/2018

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Beschreibung / Abstract

The motivation for this book was the increase in the appearance of ferroresonance oscillation in substations. The price pressure on the operating authorities and as well on component manufacturers i.e. for instrument transformer, power transformer and grading capacitors for high-performance circuit breakers has led to gradually increasing demands on power system and components.

In the IEC Dictionary the following definition can be found for ferroresonance: "a resonance of the capacitance of an apparatus with the inductance of saturable magnetic circuit of an adjacent apparatus".

Ferroresonance refers to non-linear oscillations that can occur in power systems where inductive components with a ferromagnetic core, together with capacitances and an AC voltage source comprise a system capable of oscillation.

In contrast to a linear resonant circuit, a circuit with non-linear inductance exhibits no well-defined resonance frequency. A sinusoidal source voltage of a fixed frequency can excite different frequencies (harmonic and subharmonic frequencies). In addition, the amplitude of the excited oscillations is not limited only by the power loss in the resonant circuit. For each oscillation mode, a resultant oscillation amplitude can be found.

This book provides an overview of the undesired phenomenon of ferroresonance oscillations in high and medium voltage networks in connection with the inductive voltage transformers (VT). Ferroresonance oscillations can cause considerable damage to the VT and neighboured equipment. Because of the various forms of manifestation, cases of ferroresonance are not always recognized as such.

The book is addressed to designers and operators of high voltage power installations and manufacturers of inductive voltage transformers.

Leseprobe

Inhaltsverzeichnis

  • Ferroresonance Oscillations in Substations
  • Foreword
  • Contents
  • 1 Introduction to ferroresonance oscillations
  • 1.1 Scope
  • 1.2 Forced oscillations in non-linear resonance circuits, general considerations
  • 1.3 Excitation of steady state and non-steady state ferroresonance oscillations
  • 1.4 Inductive voltage transformer
  • 1.5 Non-linear magnetization characteristic
  • 2 Theoretical considerations of non-linear oscillations
  • 2.1 The first solution by Rüdenberg, graphical treatment for power frequency ferroresonance oscillations
  • 2.2 Voltage and current during a single period of ferroresonance oscillation at power frequency
  • 2.3 Analytical description of oscillations in non-linear circuits
  • 3 Single-phase ferroresonance oscillation
  • 3.1 Introduction
  • 3.2 General schematic diagram for single-phase ferroresonance
  • 3.3 Practical cases of ferroresonance configurations
  • 3.4 Parameters relevant ferroresonance
  • 3.5 Ferroresonance in CVTs
  • 3.6 The simplification of non-linear electrical circuits with the theorem of Thévenin
  • 4 Three-phase ferroresonance oscillations
  • 4.1 Introduction
  • 4.2 Resulting Waveform of three-phase Ferroresonance Oscillations
  • 4.3 Physical explanation for the beat
  • 4.4 Practical example
  • 4.5 Results of field tests
  • 4.5.1 Example 1
  • 4.5.2 Example 2
  • 4.5.3 Example 3
  • 4.5.4 Example 4
  • 5 Simulation of ferroresonance oscillations
  • 5.1 Schematic circuit and circuit elements of single phase ferroresonance configuration
  • 5.2 Circuit losses
  • 5.3 Magnetization curve
  • 5.4 Characterization of ferroresonance oscillations
  • 5.5 Discussion of single phase ferroresonance behavior
  • 5.6 Simulation of three phase ferroresonance oscillations
  • 6 Detection and measurement of ferroresonance oscillations
  • 6.1 Introduction
  • 6.2 Detection of ferroresonance oscillations
  • 6.3 Measurement of ferroresonance oscillations
  • 7 Prevention and measures against ferroresonance oscillations
  • 7.1 Overview of measures to avoid ferroresonance oscillations
  • 7.2 Definition of switching procedures to avoid ferroresonance oscillations
  • 7.3 Measures in new substation projects
  • 7.4 Existing substations
  • 7.5 Overview and conclusions
  • 8 List of symbols
  • Literature
  • Subject Index

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