Question

The Surge Impedance of a 3-Phase 400kV transmission line is 400ohm. The Surge Impedance Loading (SIL) is:

• A. 400 MW
• B. 100 MW
• C. 1600 MW
• D. 200 MW

Hint:

The Surge Impedance Loading (SIL) is the power at which the line impedance matches the transmission line’s impedance. It is calculated as \( \frac{V^2}{Z} \).

Answer 1

The Correct Option is A

The Surge Impedance Loading (SIL) of a transmission line is given by the formula: \[ \text{SIL} = \frac{V^2}{Z} \] Where:
- \( V = 400 \, \text{kV} \) is the line voltage,
- \( Z = 400 \, \Omega \) is the surge impedance.
Substituting the values: \[ \text{SIL} = \frac{(400)^2}{400} = 400 \, \text{MW} \] Thus, the Surge Impedance Loading (SIL) is 400 MW, which corresponds to option (1).