ELEMENTS OF POWER SYSTEM

UTTARAKHAND TECH. UNIVERSITY

utu previous year question papers

B TECH (sem iv),2012

SUB:- elements of power system

time : 3hr]

Total marks :100

SECTION A

Q1:- Attempt any four of the following :

1. Compare overhead transmission system with underground transmission system with underground  transmission system on atleast 10 major grounds.
2. Differentiate the following:(a) Skin effect and proximity effect.
   (b) Circuit breaker and isolator.
3. What is the % saving in feeder copper if the line voltage in a 2-wire dc system be raised from 220 volts for the same power transmitted over same distance and having the same power loss?
4. State Kelvin's law for obtaining the size of the conductor for transmission. Discuss its limitations.
5. Describe ACSR conductor used in transmission line.
6. The cost of 3-Ф overhead line having cross-section area 'a' Cm² is Rs. (500+2,000a) per kilometer. Calculate the most economical current density for the most economical current density for the conductor if the rate of interest and depreciation is 12% per annum and the cost of energy wasted is 5 paise per kWh. The resistivity of conductor may be taken as (1.7/a) ohm/km. Take load factor of 12%.