Cochin University of Science and Techology (CUST) 2011-6th Sem B.Tech Electrical and Electronics Engineering BTech ,il - EE 601 POWER SYSTEM I (2006 Scheme) - Question Paper
BTS (C)- VI -11-Oil-Q
B.Tech Degree VI Semester Examination April 2011
EE 601 POWER SYSTEM I
(2006 Scheme)
Time : 3 Hours Maximum Marks : 100
PART - A
(Answer ALL questions)
(8x5= 40)
I. (a) What is tariff and what are the objectives of tariff?
(b) Define:
(i) connected load (ii) load factor
(iii) demand factor (iv) diversity factor
(c) Write a short note on Pin type insulators.
(d) Derive an expression for capacitance of a single core cable.
(e) Compare overhead and under ground systems.
(f) State and explain Kelvins law.
(g) Write a short note on short transmission line, medium transmission line and long transmission line.
(h) Derive an expression for ABCD parameter for a short transmission line.
PART-B
(4x15 = 60)
II. With neat diagram explain the working of a thermal power plant. (15)
OR
III. (a) The monthly reading of a consumers meter are as follows :
Maximum demand - 50 KW Energy consumed - 36,000 KWh
Reactive energy - 23,400 KVAR
If the tariff is Rs. 80/KW of maximum demand plus 8 paise per unit plus 0.5 paise per unit of each 1% of power factor below 86%, calculate monthly bill of the consumer? (8)
(b) Explain power factor improvement by synchronous condenser. What are the
advantages and disadvantages of this method? (7)
IV. (a) Write a short note on line supports. (5) (b) An insulator string consists of three units, each having a safe working voltage of
15 KV. The ratio of self capacitance to shunt capacitance of each unit is 8:1. Find the maximum safe working voltage of the string. Also find string efficiency. (10)
OR
V. (a) What are the factors affecting corona? Define :
(i) Critical disruptive voltage
(ii) Visual critical voltage. (8)
(b) What is sag? Derive an expression for sag when supports are at equal levels. (7)
VI. (a) Give the single line diagram of a typical distribution system. (5) (b) Derive an expression for the voltage drop for a uniformly loaded distributor fed at
one end. (10)
OR
VII. (a) What are the limitations of Kelvins law? (5) (b) A conductor cable 1 Km long is required to supply a constant current of 200 A
throughout the year. The cost of cable including installation is Rs. (20 a + 20) per metre where a is the area of cross section of the conductor in cm2. The cost of energy is 5 p per KWh and interest and depreciation charges amount to 10%. Calculate the most economical conductor size. Assume resistivity of conductor material as 1.73 fJ.15 cm. 0)
VIII. Derive an expression for ABCD parameter of a long transmission line by Rigorous method. (15)
OR
IX. (a) What are the importance of voltage control? (5)
(b) Give the various locations of voltage control equipment. (3)
(c) Derive an expression for ABCD constants of a medium transmission line by nominal T method. (7)
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