POWER SYSTEMS-1 JNTU previous years question papers

POWER SYSTEMS-1 JNTU previous years question papers


Time: 3 hours Max Marks: 80
Answer Any FIVE Questions
All Questions carry equal marks

1. Describe the schematic arrangement of a thermal power station and explain the function of each part briefly? [16]

2. [a] Describe the different types of fuels used in a nuclear power plant and discuss the problems of nuclear waste disposal? [10]
[b] Discuss briefly the radio – active pollution of environment by nuclear power plant ?[6]

3. [a] What is meant by radial and loop systems of distribution? Discuss briefly the requirements of a distribution system. [8]
[b] A 2- wire DC ring distributor is 300 m long and is fed at 240 v at point A. At point B, 150m fromA, a load of 120 A is taken and at C, 100 m in the opposite direction, a load of 80 A is taken if the resistance per 100 m of single conductor is 0.03  , find
i] Current in each section of distributor
ii] Voltage at point B and C [8]

4. A 3  distribution system power is supplied at 11 KV[ line voltage] and the balanced load of 50 A/phase at 0.8 lagging p.f and 70 A at 0.9 lagging p.f are taken at Q and R respectively. The impedance of the feeders are PQ=[5+j9]  , QR=[6+j10] , and RP= [4+j8]. Calculate the voltage at Q and R and the current in each branch. Power factors are assumed with respect to voltage at P. [16]

5. [a] Explain the main and transfer bus bar system with circuit diagram ? [8]
[b] What are the merits and demerits of indoor substations over outdoor substations.[8]

6. [a] Why voltage control and power factor correction are necessary in power systems?What are the disadvantages of low voltage and low p.f of the system? [8]
[b] A 400 v, 50 cycles, 3  line delivers 207 KW at 0.8 p.f[lag]. It is desired to bring the line p.f to unity by installing shunt capacitors. Calculate the capacitance if they are
i] Star connected
ii] Delta connected [8]

7. [a] Define the following terms [8]
i] Plant capacity factor
ii] Plant use factor
iii] Demand factor
iv] Maximum demand.
[b] A generating station has the following daily load cycle.
Time[hrs] 0-6 6 – 10 10 – 12 12 - 16 16 – 20 20 – 24
Load [MW] 30 40 20 70 50 40
Draw the load curve and find [i] Maximum demand. [ii] Units generated per day [iii]Average load and load factor.

8. [a] Discuss the flat rate and block rate tariff’s? [8]
[b] What are the factors influencing the tariff design? [8]

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