Reactive Power Direction
A phase-angle view of how P, Q, S, and power factor move together.
Reactive Power Direction
A phase-angle view of how P, Q, S, and power factor move together.
Control visualization - move the phase angle to compare lagging and leading reactive power behavior.
What it shows
Active power P (kW), reactive power Q (kVAr), and apparent power S (kVA) form a right triangle: S² = P² + Q². The angle φ between voltage and current sets the split. When current lags voltage the load absorbs reactive power (inductive); when it leads, it supplies reactive power (capacitive). Power factor is cos φ = P/S.
Why it matters for BESS
A grid-scale inverter is sized in kVA but paid mostly for kW — and grid codes require it to absorb or supply kVAr on demand. Seeing P, Q, and S as one triangle makes the trade-off explicit: every kVAr of reactive support eats into the kW headroom of the same kVA rating.
Frequently asked
- What is the difference between active, reactive, and apparent power?
- Active power (kW) does real work; reactive power (kVAr) shuttles energy back and forth to sustain magnetic and electric fields; apparent power (kVA) is the vector sum the equipment must actually carry.
- What does lagging vs leading power factor mean?
- Lagging means current lags voltage and the load is net inductive (absorbing reactive power); leading means current leads voltage and the load is net capacitive (supplying reactive power).