Surge Impedance Loading

Surge impedance of a line, Zo

A transmission line loaded to its surge impedance loading:

(i) has no net reactive power flow into or out of the line, and

(ii) will have approximately a flat voltage profile along its length.

 

For (i) to hold:

This means that there will be no net reactive power flow at surge-impedance loading.

 

For (ii) to hold:

This means that the line will have a flat voltage profile, i.e., no voltage drop.