The underground system
The underground system cannot be operated above:
(A) 440 V
(B) 11 kV
(C) 33 kV
(D) 66 kV
Answer: (D) 66 kV
Explanation:
The underground system cannot be operated above 66 kV because of insulation difficulties but the overhead system can be designed for operation up to 400 kV or higher.
