1. Attempt the following objective type questions
A short circuit current is identified by heavy current flow

(ii) voltage rise

(iii) voltage drop

(iv) None of these Which of the following is usually not the generating voltage? 6.6 kV

(ii) 9.9 kV

(iii) 11 kV

(iv) 13.2kV HVDC transmission needs d.c. generators

(ii) a.c. filters

(iii) pulse converters

(iv) d.c. filters For cost and safety, the outdoor substations are employed for voltages 11 kV and above

(ii) 33 kV and above

(iii) 66 kV and above
110 kV and above Two part tariff is charged on the basis of connected load

(ii) units consumed

(iii) maximum demand

(iv) Both and Static capacitors for power factor improvement are rated in terms of kVAR

(ii) kVA

(iii) kW

(iv) kWh The most common type of fault is LG

(ii) LL

(iii) LLG

(iv) LLLG

2.(a) Compare overhead line with underground cables as a medium of power transmission. Derive an expression for sag of a line supported between two supports of the same height.

3. A single-phase a.c. distributor, 500 m long, has a total impedance of (0.02 j 0.04) n and is fed from one end at 250 V. It is loaded as under: 50 A at unity p.f.200 m from feeding point 100 A at 0.8 p.f. lagging 300 m from feeding point 50 A at 0·6 p.f. lagging at the far end

Calculate the voltage drop and voltage at the far end. <img src='./qimages/8801-3c.jpg'> <br><br>

4. Draw the complete layout of a 33/11 kV distribution substation. Explain the function of its various equipments and accessories.

5.(a) What are the causes and disadvantages of low power factor? Explain the methods of power factor improvement.

6. What is the purpose of earthing Distinguish between system earthing and equipment earthing. Explain the voltage transformer earthing in detail.

7. Write short notes on any four of the following Two Part Tariff Pole Mounted Substation HVDC Transmission Line String Insulator Corona on Transmission Line