HIGH VOLTAGE ENGINEERING(3:1:0),
8th Sem. B.Tech(Electrical), VSSUT
MODULE-I (10 HOURS)
Conduction and breakdown in gases: Gases as insulating media, Ionisation processes. Townsend
current growth equation. Current growth in the presence of secondary processes. Townsend’s
criterion for breakdown. Experimental determination of ionization coefficients.
Breakdown in electronegative gases, time lags for breakdown, streamer theory of breakdown
in gases, Paschen’s law, Breakdown in non-uniform field and corona discharges,
Post breakdown phenomena and applications, practical considerations in using gases for
insulation purposes.
MODULE-II (10 HOURS)
Conduction and breakdown in liquid dielectrics: Pure liquids and commercial liquids, conduction
and breakdown in pure liquids.
Breakdown in solid dielectrics: Introduction, Intrinsic brakdown. Electromechanical breakdown,
Thermal breakdown.. Breakdown of solid dielectrics in practice.
MODULE-III (10 HOURS)
Generation of high voltage and currents: Generation of high D.C, voltages, Generation of high
alternating voltages, Generation of Impulse voltages. Tripping and control of impulse generators.
Generation of Impulse currents.
Measurements of high voltages and currents: Measurement of high D.C. voltages. Measurement
of high D.C. and impulse voltages. Introduction.. Measurement of high D.C. A.C. and impulse
currents, cathode ray oscillographs for impulse voltages and currents measurements.
MODULE-IV (10 HOURS)
Non destructive testing of materials and electrical apparatus: Introduction. Measurement of D.C.
resistivity. Measurement of dielectric constant and loss factor. Partial discharge measurements.
High voltage testing of electrical apparatus: Testing of insulators and bushings. Testing of
isolators and circuit breakers, cables. Testing of transformers, surge diverter
Radio Interference measurements.
BOOKS
1. M.S. Naidu and V. Kamaraju, High Voltage Engineering, Tata McGraw-Hill, 4th
Edition, 2009.
2.E.Kuffel, W.S. Zaengl, and J.Kuffel “High Voltage Engineering Fundamentals”,
Second edition 2000, published by Butterworth-Heinemann
3.C.L.Wadhwa, “High Voltage Engineering”, Third Edition, New Age International
Publishers
, To
Dedicated to all my students who
made me learn this subject.
, MODULE-I
Electrical materials constitute an extreme group of industrial materials that go
specifically for manufacture of electrical machines, electrical apparatus,
instruments, and other elements of electrical equipment and installations.
By the behaviour in an electric and magnetic field, or both, we ordinarily
categorize all of these materials into major groups.
1. Dielectric
2. Conducting
3. Semiconducting
4. Magnetic materials
Reliability of product depend on quality of materials which are defined by the
material characteristics
Electrical materials -> Thermal. Electrical, Atmospheric, Mechanical
Magnetic materials -> Magnetic characteristics
Mechanical characteristics -> Tensile strength
Compressive strength
Bending strength
Elasticity
Electrical characteristics -> Resistivity
Temperature coefficient of resistivity
Dielectric Constant
Electronic polarisation
Dielectric polarisation
Tan (loss tangent)
Breakdown strength
Atmospheric -> Viscosity
Tropical resistance
Acid number
Thermal -> Melting point
Softening point
Heat stability
Thermal Endurance
, 1. CONDUCTION AND BREAKDOWN IN GASES
The high-voltage power system, in general consists of a complex configuration of
generators, long-distance transmission lines and localized distribution networks with
above- and below-ground conductors for delivering energy to users. Associated with this
are a wide range of high-voltage components whose successful operation depends on the
correct choice of the electrical insulation for the particular application and voltage level.
The condition of the insulating materials when new, and especially as they age, is a
critical factor in determining the life of much equipment. The need for effective
maintenance, including continuous insulation monitoring in many cases, is becoming an
important requirement in the asset management of existing and planned power systems.
As the voltages and powers to be transmitted increased over the past hundred years the
basic dielectrics greatly improved following extensive research by industry and in
specialized high voltage laboratories, where much of this work continues.
BACK GROUND MATERIAL
Recollect kinetic theory of gases (Developed by Maxwell)
PV=nRT where numerically R is equal to 8.314 joules/ Kmol.
The fundamental equation for the kinetic theory of gas is derived with the following
assumed conditions:
Gas consists of molecules of the same mass which are assumed spheres.
Molecules are in continuous random motion.
Collisions are elastic – simple mechanical.
Mean distance between molecules is much greater than their diameter.
Forces between molecules and the walls of the container are negligible.
1.1 Gases as Insulating Media
The most common dielectrics are gases. Many electrical apparatus use air as the
insulating medium, while in a few cases other gases such as N2, CO2, CCl2 F2 (freon) and
SF6 (hexafluoride) are used.
Gases consist of neutral molecules, and are, therefore, good insulators. Yet under certain
conditions, a breakdown of the insulating property occurs, and current can pass through
the gas. Several phenomena are associated with the electric discharge in gases; among
them are spark, dark (Townsend) discharge, glow, corona, and arc.
8th Sem. B.Tech(Electrical), VSSUT
MODULE-I (10 HOURS)
Conduction and breakdown in gases: Gases as insulating media, Ionisation processes. Townsend
current growth equation. Current growth in the presence of secondary processes. Townsend’s
criterion for breakdown. Experimental determination of ionization coefficients.
Breakdown in electronegative gases, time lags for breakdown, streamer theory of breakdown
in gases, Paschen’s law, Breakdown in non-uniform field and corona discharges,
Post breakdown phenomena and applications, practical considerations in using gases for
insulation purposes.
MODULE-II (10 HOURS)
Conduction and breakdown in liquid dielectrics: Pure liquids and commercial liquids, conduction
and breakdown in pure liquids.
Breakdown in solid dielectrics: Introduction, Intrinsic brakdown. Electromechanical breakdown,
Thermal breakdown.. Breakdown of solid dielectrics in practice.
MODULE-III (10 HOURS)
Generation of high voltage and currents: Generation of high D.C, voltages, Generation of high
alternating voltages, Generation of Impulse voltages. Tripping and control of impulse generators.
Generation of Impulse currents.
Measurements of high voltages and currents: Measurement of high D.C. voltages. Measurement
of high D.C. and impulse voltages. Introduction.. Measurement of high D.C. A.C. and impulse
currents, cathode ray oscillographs for impulse voltages and currents measurements.
MODULE-IV (10 HOURS)
Non destructive testing of materials and electrical apparatus: Introduction. Measurement of D.C.
resistivity. Measurement of dielectric constant and loss factor. Partial discharge measurements.
High voltage testing of electrical apparatus: Testing of insulators and bushings. Testing of
isolators and circuit breakers, cables. Testing of transformers, surge diverter
Radio Interference measurements.
BOOKS
1. M.S. Naidu and V. Kamaraju, High Voltage Engineering, Tata McGraw-Hill, 4th
Edition, 2009.
2.E.Kuffel, W.S. Zaengl, and J.Kuffel “High Voltage Engineering Fundamentals”,
Second edition 2000, published by Butterworth-Heinemann
3.C.L.Wadhwa, “High Voltage Engineering”, Third Edition, New Age International
Publishers
, To
Dedicated to all my students who
made me learn this subject.
, MODULE-I
Electrical materials constitute an extreme group of industrial materials that go
specifically for manufacture of electrical machines, electrical apparatus,
instruments, and other elements of electrical equipment and installations.
By the behaviour in an electric and magnetic field, or both, we ordinarily
categorize all of these materials into major groups.
1. Dielectric
2. Conducting
3. Semiconducting
4. Magnetic materials
Reliability of product depend on quality of materials which are defined by the
material characteristics
Electrical materials -> Thermal. Electrical, Atmospheric, Mechanical
Magnetic materials -> Magnetic characteristics
Mechanical characteristics -> Tensile strength
Compressive strength
Bending strength
Elasticity
Electrical characteristics -> Resistivity
Temperature coefficient of resistivity
Dielectric Constant
Electronic polarisation
Dielectric polarisation
Tan (loss tangent)
Breakdown strength
Atmospheric -> Viscosity
Tropical resistance
Acid number
Thermal -> Melting point
Softening point
Heat stability
Thermal Endurance
, 1. CONDUCTION AND BREAKDOWN IN GASES
The high-voltage power system, in general consists of a complex configuration of
generators, long-distance transmission lines and localized distribution networks with
above- and below-ground conductors for delivering energy to users. Associated with this
are a wide range of high-voltage components whose successful operation depends on the
correct choice of the electrical insulation for the particular application and voltage level.
The condition of the insulating materials when new, and especially as they age, is a
critical factor in determining the life of much equipment. The need for effective
maintenance, including continuous insulation monitoring in many cases, is becoming an
important requirement in the asset management of existing and planned power systems.
As the voltages and powers to be transmitted increased over the past hundred years the
basic dielectrics greatly improved following extensive research by industry and in
specialized high voltage laboratories, where much of this work continues.
BACK GROUND MATERIAL
Recollect kinetic theory of gases (Developed by Maxwell)
PV=nRT where numerically R is equal to 8.314 joules/ Kmol.
The fundamental equation for the kinetic theory of gas is derived with the following
assumed conditions:
Gas consists of molecules of the same mass which are assumed spheres.
Molecules are in continuous random motion.
Collisions are elastic – simple mechanical.
Mean distance between molecules is much greater than their diameter.
Forces between molecules and the walls of the container are negligible.
1.1 Gases as Insulating Media
The most common dielectrics are gases. Many electrical apparatus use air as the
insulating medium, while in a few cases other gases such as N2, CO2, CCl2 F2 (freon) and
SF6 (hexafluoride) are used.
Gases consist of neutral molecules, and are, therefore, good insulators. Yet under certain
conditions, a breakdown of the insulating property occurs, and current can pass through
the gas. Several phenomena are associated with the electric discharge in gases; among
them are spark, dark (Townsend) discharge, glow, corona, and arc.
