1

GATE EE 1999

Subjective

+5

-0

A 66 kV, 3-phase, 50 Hz, 150 km long overhead transmission line is open circuited at the receiving end. Each conductor has a resistance of 0.25$$\Omega $$/km, an inductive reactance of 0.5$$\Omega $$/km and a capacitive admittance to neutral of 0.04 $$ \times $$ 10

^{-4}S/km.(a) Draw the nominal π-equivalent circuit and indicate the value of each parameter.

(b) Calculate the receiving end voltage if the sending end voltage is 66 kV.

^{}2

GATE EE 1999

Subjective

+5

-0

A 6.6 kV, 50 Hz single core lead sheathed cable has the following data:

Conductor diameter: 1.5 cm, length: 4 km. Internal diameter of the sheath : 3 cm

Resistivity of insulation : 1.3 $$ \times $$ 1012 $$\Omega $$-m. Relative permittivity of insulation : 3.5 Calculate

Conductor diameter: 1.5 cm, length: 4 km. Internal diameter of the sheath : 3 cm

Resistivity of insulation : 1.3 $$ \times $$ 1012 $$\Omega $$-m. Relative permittivity of insulation : 3.5 Calculate

(a) the insulation resistance

(b) the capacitance and

(c) the maximum electric stress in the insulation

3

GATE EE 1998

Subjective

+5

-0

Each conductor of a $$33$$ $$kV,$$ $$3$$ phase system is suspended by a string of three similar insulators. The ratio of shunt capacitance to mutual capacitance is $$0.1.$$ Calculate the voltage across each insulator, and the string efficiency.

4

GATE EE 1997

Subjective

+5

-0

A factory draws $$100$$ kW at $$0.7$$ p.f. lagging from a $$3$$-phase, $$11$$ kV supply. It is desired to the p.f. to $$0.95$$ lagging using series capacitors. Calculate the rating of the capacitor required.

Questions Asked from Parameters and Performance of Transmission Lines (Marks 5)

Number in Brackets after Paper Indicates No. of Questions

GATE EE Subjects

Electromagnetic Fields

Signals and Systems

Engineering Mathematics

General Aptitude

Power Electronics

Power System Analysis

Analog Electronics

Control Systems

Digital Electronics

Electrical Machines

Electric Circuits