JNTU Kakinada B-Tech 4-2 HIGH VOLTAGE ENGINEERING R13 April 2018 Question Paper

IV B.Tech II Semester Regular/Supplementary Examinations, April – 2018
HIGH VOLTAGE ENGINEERING (Electrical and Electronics Engineering)Time: 3 hours Max. Marks: 70
Question paper consists of Part-A and Part-B
Answer ALL sub questions from Part-A
Answer any THREE questions from Part-B
*****

PART ?A (22 Marks)1. a) Define uniform and non-uniform electric field. [3]
b) Explain breakdown procedure in pure liquids. [4]
c) Write the specifications of impulse voltage and current wave forms. [4]
d) Explain about peak voltmeters. [4]
e) Write a short note on the use of an Oscilloscope as a PD measuring device. [4]
f) Explain about the 50% dry impulse flash over test. [3]

PART ?B (3×16 = 48 Marks)2. a) Discuss about the finite difference method for electric field computation. [8]
b) Compare different numerical methods used in field computation. [8]

3. a) Explain difference between photo-ionization and photo-electric emission? [8]
b) Explain short term and long term breakdown mechanisms that occur in a
composite solid dielectrics?
[8]

4. a) Explain tripping and control of impulse generators. [8]
b) Explain with diagrams different types of rectifier circuits to produce high D.C
Voltages.
[8]

5. a) What are the different types of resistive shunts used for impulse current
measurements? Discuss their characteristics and limitation.
[8]
b) Describe generating voltmeter used for measuring high d.c voltages. How
does it compare with a potential divider for measuring high dc currents.
[8]

6. a) The lossless standard capacitor used in high voltage Schering Bridge has a value
100 pF. In a certain measurement, the other arms of the bridge at balance are (i) a
resistance of 641 ohms and (ii) a capacitance of 0.052 ?F in parallel with a
resistance of 2500 ohms. Determine capacitance and loss tangent of the specimen
at 50 Hz.

[8]
b) How partial discharges are measured using straight detectors? [8]

7. a) What is significance of impulse tests? Briefly explain impulse testing of
insulators.
[8]
b) Mention different electrical tests done on isolators. [8]
Code No: RT42022B
Set No. 1
R13
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