1.a) Derive the expression for capacitance of an unsymmetrical three phase system regularly transposed.
b) What is the effect of ground on transmission line capacitance? [15]
2.a) Explain the classification of transmission lines.
b) Derive the expression for regulation and efficiency of a medium line using end conductor method. Draw the phasor diagram. [15]
3. Explain how long lines are represented by equivalent Π model. [15]
4. Derive the expression for wave equation of a traveling wave. [15]
5.a) Explain the factors affecting corona loss in transmission lines.
b) A 3-φ, 220 k v, 50 Hz transmission line has equilateral triangular spacing of 2m side. The conductor diameter is 3 cm. The air density factor and surface irregularity factor are 0.95 and 0.83 respectively. Find critical disruptive voltage and corona loss per kilometer. [15]
6.a) Explain about various types of insulators used for overhead transmission lines.
b) A string of suspension insulators consists of three units. The capacitance between each pin and earth is 15% of the self capacitance of the unit. If the maximum peak voltage per unit is not to exceed 35kv, find the working voltage and string efficiency. [15]
7.a) What is a sag template? What are its advantages?
b) Calculate the minimum sag permissible for a 160 m span, 1 cm dia copper conductor allowing a maximum tensile stress of 2000 kg/cm2. Assume a wind pressure of 4 kg/cm2 of projected area and ice coating of 1 cm. Specific gravity of copper is 8.9 gm/cm3. [15]
8.a) By means of a diagram describe the construction of a underground cable.
b) The inner and outer diameter of a cable are 3 cm and 8 cm respectively. The cable is insulated with two materials having permittivity of 5 and 3.5 with corresponding stresses of 38 kv/cm and 30kv /cm. calculate the radial thickness of each insulating layer and the safe working voltage of the cable. [15]
b) What is the effect of ground on transmission line capacitance? [15]
2.a) Explain the classification of transmission lines.
b) Derive the expression for regulation and efficiency of a medium line using end conductor method. Draw the phasor diagram. [15]
3. Explain how long lines are represented by equivalent Π model. [15]
4. Derive the expression for wave equation of a traveling wave. [15]
5.a) Explain the factors affecting corona loss in transmission lines.
b) A 3-φ, 220 k v, 50 Hz transmission line has equilateral triangular spacing of 2m side. The conductor diameter is 3 cm. The air density factor and surface irregularity factor are 0.95 and 0.83 respectively. Find critical disruptive voltage and corona loss per kilometer. [15]
6.a) Explain about various types of insulators used for overhead transmission lines.
b) A string of suspension insulators consists of three units. The capacitance between each pin and earth is 15% of the self capacitance of the unit. If the maximum peak voltage per unit is not to exceed 35kv, find the working voltage and string efficiency. [15]
7.a) What is a sag template? What are its advantages?
b) Calculate the minimum sag permissible for a 160 m span, 1 cm dia copper conductor allowing a maximum tensile stress of 2000 kg/cm2. Assume a wind pressure of 4 kg/cm2 of projected area and ice coating of 1 cm. Specific gravity of copper is 8.9 gm/cm3. [15]
8.a) By means of a diagram describe the construction of a underground cable.
b) The inner and outer diameter of a cable are 3 cm and 8 cm respectively. The cable is insulated with two materials having permittivity of 5 and 3.5 with corresponding stresses of 38 kv/cm and 30kv /cm. calculate the radial thickness of each insulating layer and the safe working voltage of the cable. [15]
No comments:
Post a Comment