JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD

Prerequisite

Electromagnetic Fields

Course Objectives:

• To gain in-depth knowledge on characteristics and behavior of dielectrics under static and alternating fields.
• To study the breakdown mechanism of gaseous, liquid and solid dielectrics.

Course Outcomes

After the completion of this course, the student will be able to

• Know the properties of various dielectric materials.
• Understand the fundamental behavior of gaseous, liquid, and solid dielectrics.
• Emphasize the breakdown phenomenon of dielectric materials.

UNIT - I

Dielectrics and Insulating Material: Review of Dielectric Phenomenon: Complex permittivity – Polarization – Relaxation and resonant models. Solid, Liquid and Gaseous insulating materials.

UNIT - II

Properties of Dielectrics and Insulating Materials: Physical Thermal & Electrical properties- Classification of Insulating Materials, Solid Materials: Organic Fiber materials Ceramics & Synthetic polymeric and their applications. Liquid Materials: Insulating oils their properties and applications. Gaseous Materials: Air and SF6 – applications in electrical apparatus.

UNIT - III

Breakdown Phenomenon – I: Insulation and decay process-transition from self sustained discharges to breakdown. Townsend and streamer discharge paschen’s law penning effect-Time lags-Surge breakdown voltage.

UNIT - IV

Breakdown Phenomenon – II: Breakdown in non uniform fields-Vacuum insulation and vacuum breakdown. Breakdown Phenomenon in Liquid and Solid insulation: pure and commercial liquids- suspended particle and bubble theories-stressed oil volume theory.

UNIT - V

Breakdown Phenomenon – III: Breakdown in solid insulation intrinsic breakdown-Treeing and tracking phenomenon-Thermal breakdown-Breakdown in composite dielectrics.

REFERENCE BOOKS:

• 1. High Voltage Engineering – by E. Kuffel and W.S. Zaenal Pergamon press. Oxford 1984.
• 2. High Voltage Engineering – by M.S. Naidu and V. Kamarajuu, Tata McGraw Hill Book Co., New Delhi, 2nd edition, 1995.
• 3. Electrical Engineering Materials – B. Tareev, M.I.R. Publications, Moscow.
• 4. A Physics of Dielectrics – B. Tareev, M.I.R. Publications, Moscow.
• 5. High Voltage Technology – LL Alston, Oxford University Press 1968.