JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD
JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD B.Tech III HIGH VOLTAGE ENGINEERING Previous Question Paper (January/February - 2023 - R18)
Note: i) Question paper consists of Part A, Part B. ii) Part A is compulsory, which carries 25 marks. In Part A, Answer all questions. iii) In Part B, Answer any one question from each unit. Each question carries 10 marks and may have a, b as sub questions.
Part A
What is ionization process?
Answer
Ionization is the process by which a neutral atom or molecule gains or loses an electron, thereby becoming a charged ion. In high voltage engineering, this typically occurs through collisions with high-energy electrons, radiation, or thermal excitation, leading to the formation of charge carriers that facilitate electrical conduction in gases, liquids, or solids.
Give brief about composite dielectrics.
Answer
Composite dielectrics consist of two or more different insulating materials used in combination to improve the overall dielectric strength and performance of an insulation system. By combining materials with different properties, such as high mechanical strength and high electrical resistivity, the resulting composite can withstand higher voltage stresses and minimize the risk of total breakdown compared to a single material.
What are the various methods to generate high impulse currents?
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Explain the working principle of Vande-Graff generator.
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What are the methods to generate peak voltage?
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Define dielectric constant.
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How do switching over voltages are generated?
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Define surge. What are lightening surges?
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List out various high voltage equipment.
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List IS standards for high voltage testing.
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Part B
Explain the process of breakdown in pure and commercial liquids with suitable diagrams.
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Obtain the Townsend’s current growth equation. Explain Townsend’s criteria for air breakdown.
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Design voltage doubler circuits to generate high DC voltage.
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Draw and explain cascade transformer to generate high AC voltage.
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Design and discuss about cathode ray oscillographs for impulse voltage measurement.
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Explain in detail various techniques for the measurement of high DC voltages.
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Explain different methods employed for lightning protection.
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With a neat sketch, explain the working principle of an expulsion type lighting arrestor.
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Discuss the different high voltage tests conducted on bushings.
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With neat diagrams, explain various methods of testing circuit breaker.
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