Question Paper Code : 41026
B.E./B.Tech. DEGREE EXAMINATIONS, NOVEMBER/DECEMBER 2024.
Fifth/Sixth/Seventh Semester
Electrical and Electronics Engineering
EE 3037 — POWER SYSTEM TRANSIENTS
(Common to : )
(Regulations 2021)
Answer ALL questions.
PART A — (10 × 2 = 20 marks)
- 1.
What is the cause of transients?
- 2.
Using Laplace transform how do you express voltage across capacitance with initial condition?
- 3.
Distinguish between resistance switching and load switching.
- 4.
Define Ferro resonance.
- 5.
What are the effects of lightning transients?
- 6.
What is the role of ground wires to protect against lightning?
- 7.
What is a travelling wave?
- 8.
What are the advantage of Bewley's lattice diagram.
- 9.
Draw the voltage transient waveform which occur due to closing of lines.
- 10.
Define transient over voltage factor.
PART B — (5 × 13 = 65 marks)
- 11.(a)
- (i)Discuss about the different sources of transients occuring in power system.(6)
- (ii)Explain the importance of study of transients in a system planning.(7)
- Or
- (b)
A series RL circuit consists of a resistor with a resistance of 100 ohms and an inductor with an inductance of 0.2 H. A sinusoidal voltage source with an amplitude of 10 volts and a frequency of 50 Hz is connected to the circuit, At time t=0 , the voltages source is turned on. Calculate the following:
- (i)The time constant of the circuit.(4)
- (ii)The peak current in the circuit during the transient response.(4)
- (iii)The time it takes for the current to reach 90% of its steady-state value.(5)
- 12.(a)
Write short note on the following:
- (i)Capacitor switching with multiple restricts.(7)
- (ii)Transient due to load switching.(6)
- Or
- (b)
Elaborately discuss about normal and abnormal switching transients. draw relevant diagrams.
- 13.(a)
Explain the theory of cloud formation.
- Or
- (b)
- (i)Discuss the characteristics of lightning strokes.(6)
- (ii)Evaluate the interaction between lightning and power system.(7)
- 14.(a)
Consider a transmission line with a length of 50 meters and a characteristic impedance of 75 ohms. If the frequency of the input signal is 1 GHZ, calculate:
- (i)The wavelength of the signal in the transmission line.(4)
- (ii)The natural frequency or resonant frequency of the transmission line.(4)
- (iii)Determine whether standing waves will be formed on the transmission line at this frequency.(5)
- Or
- (b)
- (i)Derive the reflection and refraction coefficients of a travelling wave.(6)
- (ii)Describe the transient response of systems with series and shunt lumped parameters.(7)
- 15.(a)
Write short note on the following:
- (i)Short line and kilometric fault.(7)
- (ii)Nature of over voltages produced by faults.(6)
- Or
- (b)
Elaborately describe about switching surges on integrated system.
PART C — (1 × 15 = 15 marks)
- 16.(a)
Develop the EMTP representation of any 6 power system parameters and explain each in detail.
- Or
- (b)
In an RLC circuit, a sinusoidal voltage source with a frequency of 100 Hz is suddenly applied across the circuit. The circuit consists of a resistor with a resistance of 50 ohms, an inductor with an inductance of 0.2 H, and a capacitor with a capacitance of 100 microF. Determine the transient response of the circuit at twice the frequency of the applied voltage. Specifically, calculate:
- (i)The angular frequency of the applied voltage.(3)
- (ii)The resonant frequency of the RLC circuit.(3)
- (iii)The expression for the transient response of the current at double the frequency.(3)
- (iv)The peak current amplitude at double the frequency.(3)
- (v)The time it takes for the current to decay to 10% of its initial of its initial amplitude at double the frequency.(3)