# A single core lead covered cable is to be designed for 132 kV to earth . Its conductor radius is 20mm and its insulating material A,B and C have relative permittivities 5,4 and 3 respectively and corresponding maximum permissible stresses of 3.6,2.4 and 2.0 kV/mm(rms) respectively. The minimum diameter of the lead steath will be

1.  190 mm

2.      125 mm

3.  150 mm

4.    173.7 mm

4
Correct Answer :

173.7 mm

Explanation :
No Explanation available for this question

# A 60 kV (rms) single core metal sheathed cable is to be graded by means of a metallic intersheath. The safe electric stress of the insutating material is 6 kV/mm (rms). The overall diameter of the intersheath is

1.  10 mm

2.   20 mm

3.     15 mm

4.       7.5 mm

4
Correct Answer :

20 mm

Explanation :
No Explanation available for this question

# A 1 km of  a three phase metal sheathed belted cable gave a measured capacitance of 0.7 µF. between one conductor and the other two conductors bunched together with the earth sheath and 1.5 µF measured between the three bunched conductors and the sheath. What is the charging current, when the cable is connected at 11 kV, 50 Hz supply

1.  0.80 A/phase

2.    1.40 A/phase

3.    1.59 A/phase

4.   1.695 A/phase

4
Correct Answer :

1.59 A/phase

Explanation :
No Explanation available for this question

# The capacitance of a 3 core lead sheathed cable measured between any two of the conductors with sheath earthed is 0.19 µF per km. The kvA required to keep 16 kms of the cable charged when connected to 20 kV, 50 Hz supply will be

1.  720 kVA

2.  780 kVA

3.   763 kVA

4.  600 kVA

4
Correct Answer :

763 kVA

Explanation :
No Explanation available for this question

# If the sheath resistance is 2.14 /km and that of the conductor is 0.1625 ?/km, and mutual inductance of the sheath is 3.13 ×10-7 H/m. When the cable is 2 km long, and supply is 50 Hz, the ration of sheath loss to core loss of the cable will be

1.  0.35

2.   0.277

3.   0.0277

4.    0.0354

4
Correct Answer :

0.0277

Explanation :
No Explanation available for this question

# What is the corona loss of a 3-phase line, 160 km long, conductor diameter 1.036 cm, 2.44 delta spacing, air temperature 26o, corresponding to a barometric pressure of 72cm, operating voltage 110 KV at 50 Hz, m=0.78

1.  322 KW

2.  792 KW

3.  800 KW

4.   841 KW

4
Correct Answer :

841 KW

Explanation :
No Explanation available for this question

# A 3 phase 50 Hz, 132 KV transmission line consists of conductor of 1.17 cm diameter and spaced equilateral at a distance of 3m. The line conductors have smooth surface with value for m-0.96. The barometric pressure is 72 cm of Hg and temperature of 20oC. The corona loss in foul weather condition will be

1.  3.12 KW/km/phase

2.    4.84 KW/km/phase

3.   8.70 KW/km/phase

4.  None of these

4
Correct Answer :

3.12 KW/km/phase

Explanation :
No Explanation available for this question

# The surge impedance of a 400 km long overhead transmission line is 400 ohms. For a 200 km length of the same line, the impedance will be

1.  200

2.  800 ?

3.    400 ?

4.  100 ?

4
Correct Answer :

400 ?

Explanation :
No Explanation available for this question

# The insulation level of 400 KV EHV   overhead transmission line is decided on the basis of

1.  Lightning overvoltage

2.  Switching overvoltage

3.  Corona inception voltage

4.  Radio and TV interferance

4
Correct Answer :

Switching overvoltage

Explanation :
No Explanation available for this question

# The insulation resistance of a cable of length 10 km is 1 M. For a length of 100 km of the same cable, the insulation resistance will be

1.  1 M

2.    10 M?

3.   0.1 M?

4.   0.01 ?

4
Correct Answer :

0.1 M?

Explanation :
No Explanation available for this question

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