(A) 8 m
(B) 11 m
(C) 14 m
(D) 17 m
Answer: (A) 8 m
Explanation:
As per Indian Electricity Rule 1956, Clause No 77, the minimum distance between bottom conductor and ground of a 400KV transmission line is 8.84 meter.
the ground clearance of 220KV bottom conductor would be 7 meter.
the ground clearance of 132KV bottom conductor would be 6.1 meter.
The minimum clearance of 66KV transmission line is also taken as 6.1 meters.
An empirical formula for Found Clearance between conductors
Ground clearance=5.182+(0.305∗K)
Where:
k=V−33/33 , V in kV .
According to this, if for example the Transmission line voltage is 220 kV then first calculate K :
K=220–33/33=5.66666667
Now calculating:
Ground clearance=5.182+(0.305∗5.66666667)=6.91033333 m=7 m
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