Alternative Liquid Dielectrics for High Voltage Transformer Insulation Systems

8 Chapter 8Figure 8.1 “Free radical” mechanism of oxidation of natural esters [9, 10]....Figure 8.2 Applications of nanofluid.Figure 8.3 Two‐step nanofluid preparation methodology.Figure 8.4 Electrical double‐layer formation in a nanofluid.Figure 8.5 Forces existing in nanofluids based on DLVO theory [34].Figure 8.6 Effect of pH on the stability of nanofluids.Figure 8.7 Stability analysis of nanofluids by (a) Sedimentation method, (b)...Figure 8.8 Polarization in nanofluids [48].Figure 8.9 The internal electric field in a polarized nanoparticle [48].Figure 8.10 Methods of thermal conductivity measurement.Figure 8.11 (a) BDV and (b) Moisture content of unfilled and nanofilled vege...Figure 8.12 (a) Moisture content and (b) DP of paper aged in unfilled and na...

9 Chapter 9Figure 9.1 Silica nanoparticles, (a) XRD pattern and (b) TEM image.Figure 9.2 (a) SEM image and (b) EDAX of SiO 2nanoparticles.Figure 9.3 Schematic representation of sample preparation of nanofluid.Figure 9.4 (a) Electrical double layer for nanoparticle in liquid, (b) chemi...Figure 9.5 Particle size analysis of synthetic ester silica nanofluids in a ...Figure 9.6 Comparison of zeta potential of synthetic ester silica nanofluid ...Figure 9.7 Absolute viscosity variation with temperature of the SEF and nano...Figure 9.8 Experimental setup for frequency domain dielectric spectroscopy....Figure 9.9 Variation in dielectric constant of SEF and nanofluids with frequ...Figure 9.10 tan δ variation with frequency of SEF, Type A, Type B meas...Figure 9.11 Variation of conductivity with respect to temperature of synthet...Figure 9.12 Typical current signals recorded in SEF at an alternating polari...Figure 9.13 Variation of peak current ( I P) with voltage in SEF, Type A, and...Figure 9.14 Variation of settled current ( I S) with voltage in SEF, Type A, ...Figure 9.15 Variation of transit time ( T t) with voltage in SEF, Type A, and...Figure 9.16 Variation of Ionic mobility (μ) with voltage in SEF, Type A, and...Figure 9.17 Variation of conductivity with voltage in SEF, Type A, and Type ...Figure 9.18 Variation of ionic concentration with voltage in SEF, Type A, an...Figure 9.19 Variation of ionic radius with voltage in SEF, Type A, and Type ...Figure 9.20 Experimental setup for measurement of I–U characteristics.Figure 9.21 I–U characteristics of SEF, Type A, and Type B samples under pos...Figure 9.22 I–U characteristics of SEF, Type A, and Type B samples under neg...Figure 9.23 Experimental setup for corona discharge detection using UHF sens...Figure 9.24 Sensitivity of UHF sensor [57].Figure 9.25 Typical (a) UHF signal formed due to corona activity and (b) cor...Figure 9.26 Variation in corona inception of SEF (a) with variation in conce...Figure 9.27 PRPD analysis (a) 2.5% THD and (b) 40% THD, (i) third and fifth ...Figure 9.28 Variation in energy content of UHF signal formed due to corona a...

10 Chapter 10Figure 10.1 Duval's triangle 3 for natural esters.Figure 10.2 Duval's Pentagon 3 method for ester fluids.Figure 10.3 Experimental setup for the surface discharge activity [20].Figure 10.4 View of the hotspot fault setup.Figure 10.5 View of the arcing fault setup.Figure 10.6 Process for the preparation of the samples.Figure 10.7 Acidity of the oil samples at different oil classes.Figure 10.8 Illustration of dissolved gasses under fault conditions: (a) Min...Figure 10.9 Representation of fault gasses in Duval's triangle and Duval's P...Figure 10.10 Illustration of the degradation of the investigated dielectric ...

11 Chapter 11Figure 11.1 Comparison of fluid viscosity as function of temperature.Figure 11.2 Experiment to investigate bubbling at high load, (a) showing the...Figure 11.3 (a) Effect of water on AC dielectric strength, measured accordin...Figure 11.4 Increase in water content of fluid‐impregnated insulation paper....Figure 11.5 Aging investigations into long‐term aging of a natural ester (a)...Figure 11.6 (a) Changes in fluid DDF. Unit A was in service, unit B was stor...Figure 11.7 Oil quality measures as a function of transformer age (a) dielec...Figure 11.8 (a) Water content of oil, (b) oil temperature, (c) percentage sa...Figure 11.9 Dissolved gas concentrations for (a) methane, (b) ethylene, (c) ...Figure 11.10 Dissolved gas concentrations for (a) ethane and (b) hydrogen.Figure 11.11 One‐minute insulation resistance of transformer fleet.Figure 11.12 Ten‐minute insulation resistance of transformer fleet.Figure 11.13 Winding dielectric dissipation factor.

1 Books in the IEEE Press Series on Power Engineering

2 Cover Page

3 Series Page IEEE Press 445 Hoes Lane Piscataway, NJ 08854 IEEE Press Editorial Board Ekram Hossain, Editor in Chief Jón Atli Benediktsson Xiaoou Li Jeffrey Reed Anjan Bose Lian Yong Diomidis Spinellis David Alan Grier Andreas Molisch Sarah Spurgeon Elya B. Joffe Saeid Nahavandi Ahmet Murat Tekalp

4 Title Page

5 Copyright Page

6 Dedication Page

7 Editor Biographies

8 List of Contributors

9 Acknowledgments

10 Editorial

11 Table of Contents

12 Begin Reading

13 Index

14 Wiley End User License Agreement

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