What happens when the power factor is lagging?

What happens when the power factor is lagging?

• A. Reactive current decreases I^2R losses.
• B. Reactive current increases I^2R losses and reduces real power transfer capacity.
• C. Real power transfer increases.
• D. System voltage automatically rises.

Answer: (B)

When the power factor is lagging, the load is inductive and the current lags the voltage. This makes the current larger for the same real power transfer because P = V × I × cos(φ) and cos(φ) decreases as the angle grows. That extra current flows through the conductors and raises I^2R losses, wasting more power as heat. At the same time, the higher current reduces how much real power the line can safely transfer within its thermal limits, since more heating limits the usable capacity. The increased reactive current also contributes to bigger voltage drops along the line. So, lagging power factor leads to more reactive current, more losses, and less real power transfer capability.

When the power factor is lagging, the load is inductive and the current lags the voltage. This makes the current larger for the same real power transfer because P = V × I × cos(φ) and cos(φ) decreases as the angle grows. That extra current flows through the conductors and raises I^2R losses, wasting more power as heat. At the same time, the higher current reduces how much real power the line can safely transfer within its thermal limits, since more heating limits the usable capacity. The increased reactive current also contributes to bigger voltage drops along the line. So, lagging power factor leads to more reactive current, more losses, and less real power transfer capability.