What reactive power is
Reactive power is the portion of AC power that moves back and forth between source and load as magnetic and electric fields build and collapse.
It does not create net mechanical work or heat output like real power does, but it is necessary for equipment such as motors, transformers, solenoids, and fluorescent lighting ballasts.
Why it affects the system
Even though reactive power is not useful work, it still contributes to current flow. That current uses capacity in conductors, transformers, generators, and switchgear.
A system with high reactive demand may need larger equipment to deliver the same useful kW load.
- More current for the same real power
- Higher voltage drop under load
- Reduced spare capacity in transformers and generators
- Potential utility charges for poor power factor
How kVAR connects to kVA
kVAR, kW, and kVA form the power triangle. If kW stays constant while kVAR rises, apparent power also rises.
Managing reactive power is therefore a capacity and efficiency practice, not just a billing exercise.