T/F: power transfer capability vs line length

FALSE. Power transfer capability decreases as line length increases.

• Maximum power across a line: $P_{max} = \frac{V_s V_r}{X}$, and $X = xL$ grows with length, so $P_{max}$ falls roughly as $1/L$ (stability limit).
• Voltage drop also grows with length, so the voltage-regulation limit is reached at lower power.
• Only short lines (below about 80 km) are limited by the thermal rating, which does not depend on length.

The line capability curve shows this: power capability in multiples of SIL is about $2.75 \times SIL$ at 80 km, $1.75 \times SIL$ at 240 km and only $0.75 \times SIL$ at 640 km.