EE 1003 POWER SYSTEM TRANSIENTS 3 0 0 100

AIM

To understand generation of switching and lighting transients, their propagation, reflection and refraction a on the grid ad their impact on the grid equipment.

OBJECTIVES

i. To study the generation of switching transients and their control using circuit – theoretical concept.

ii. To study the mechanism of lighting strokes and the production of lighting surges.

iii. To study the propagation, reflection and refraction of travelling waves.

iv. To study the impact of voltage transients caused by faults,

circuit breaker action, load rejection on integrated power system.

1. INTRODUCTION AND SURVEY 5

Source of transients, various types of power systems transients, effect of transients on power systems, importance of study of transients in planning.

2. SWITCHING TRANSIENTS 10

Introduction, circuit closing transients: RL circuit with sine wave drive, double frequency transients, observations in RLC circuit and basic transforms of the RLC circuit. Resistance switching: Equivalent circuit for the resistance switching problems, equivalent circuit for interrupting the resistor current. Load switching: Equivalent circuit, waveforms for transient voltage across the load, switch; normal and abnormal switching transients. Current suppression, current chopping, effective equivalent circuit. Capacitance switching, effect of source regulation, capacitance switching with a restrike, with multiple restrikes, illustration for multiple restriking transients, ferro resonance.

3. LIGHTNING TRANSIENTS 10

Causes of over voltage, lightning phenomenon, charge formation in the clouds, rate of charging of thunder clouds, mechanisms of lighting strokes, characteristics of lightning strokes; factors contributing to good line design, protection afforded by ground wires, tower footing resistance. Interaction between lightning and power system: Mathematical model for lightning.

4. TRAVELLING WAVES ON TRANSMISSION LINE COMPUTATION OF

TRANSIENTS 10

Computation of transients: Transient response of systems with series and shunt lumped parameters and distributed lines. Travelling wave concept: step response, Bewely’s lattice diagram, standing waves and natural frequencies, reflection and refraction of travelling waves.

5. TRANSIENTS IN INTEGRATED POWER SYSTEM 10

The short line and kilometric fault, distribution of voltage in a power system: Line dropping and load rejection; voltage transients on closing and reclosing lines; over voltage induced by faults; switching surges on integrated system; EMTP for transient computation.

L = 45 Total = 45

TEXT BOOKS

1. Allan Greenwood, ‘Electrical Transients in Power Systems’, Wiley Interscience, New York, 2nd edition 1991.

2. R.D.Begamudre, ‘Extra High Voltage AC Transmission Engineering’, Wiley Eastern Limited, 1986.

REFERENCE BOOK

1. M.S.Naidu and V.Kamaraju, ‘High Voltage Engineering’, Tata McGraw Hill, 2nd edition, 2000.

AIM

To understand generation of switching and lighting transients, their propagation, reflection and refraction a on the grid ad their impact on the grid equipment.

OBJECTIVES

i. To study the generation of switching transients and their control using circuit – theoretical concept.

ii. To study the mechanism of lighting strokes and the production of lighting surges.

iii. To study the propagation, reflection and refraction of travelling waves.

iv. To study the impact of voltage transients caused by faults,

circuit breaker action, load rejection on integrated power system.

1. INTRODUCTION AND SURVEY 5

Source of transients, various types of power systems transients, effect of transients on power systems, importance of study of transients in planning.

2. SWITCHING TRANSIENTS 10

Introduction, circuit closing transients: RL circuit with sine wave drive, double frequency transients, observations in RLC circuit and basic transforms of the RLC circuit. Resistance switching: Equivalent circuit for the resistance switching problems, equivalent circuit for interrupting the resistor current. Load switching: Equivalent circuit, waveforms for transient voltage across the load, switch; normal and abnormal switching transients. Current suppression, current chopping, effective equivalent circuit. Capacitance switching, effect of source regulation, capacitance switching with a restrike, with multiple restrikes, illustration for multiple restriking transients, ferro resonance.

3. LIGHTNING TRANSIENTS 10

Causes of over voltage, lightning phenomenon, charge formation in the clouds, rate of charging of thunder clouds, mechanisms of lighting strokes, characteristics of lightning strokes; factors contributing to good line design, protection afforded by ground wires, tower footing resistance. Interaction between lightning and power system: Mathematical model for lightning.

4. TRAVELLING WAVES ON TRANSMISSION LINE COMPUTATION OF

TRANSIENTS 10

Computation of transients: Transient response of systems with series and shunt lumped parameters and distributed lines. Travelling wave concept: step response, Bewely’s lattice diagram, standing waves and natural frequencies, reflection and refraction of travelling waves.

5. TRANSIENTS IN INTEGRATED POWER SYSTEM 10

The short line and kilometric fault, distribution of voltage in a power system: Line dropping and load rejection; voltage transients on closing and reclosing lines; over voltage induced by faults; switching surges on integrated system; EMTP for transient computation.

L = 45 Total = 45

TEXT BOOKS

1. Allan Greenwood, ‘Electrical Transients in Power Systems’, Wiley Interscience, New York, 2nd edition 1991.

2. R.D.Begamudre, ‘Extra High Voltage AC Transmission Engineering’, Wiley Eastern Limited, 1986.

REFERENCE BOOK

1. M.S.Naidu and V.Kamaraju, ‘High Voltage Engineering’, Tata McGraw Hill, 2nd edition, 2000.

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