Power Factor Triangle
A practical P-Q triangle for seeing how apparent power divides into MW, MVAr, and compensation to a target PF.
Power Factor Triangle
A practical P-Q triangle for seeing how apparent power divides into MW, MVAr, and compensation to a target PF.
Control visualization - the constant-S vector sweeps through common PF points; pause, pick a PF preset, and compare the current PF with the selected target PF.
What it shows
For a fixed apparent power S (MVA), the triangle shows how much goes to real power P (MW) versus reactive power Q (MVAr) at a given power factor. Moving the target power factor shows the reactive compensation required — the MVAr you must add or absorb to move from the present operating point to the target.
Why it matters for BESS
Interconnection agreements specify a power-factor range (often 0.95 leading to 0.95 lagging) at the point of interconnection. This triangle is how engineers translate that requirement into MVAr capability and confirm the PCS rating leaves enough headroom for both real-power dispatch and reactive support.
Frequently asked
- How do you calculate reactive power for a target power factor?
- From P and the target power factor cos φ, the required reactive power is Q = P·tan(φ). The compensation needed is the difference between that target Q and the present Q.
- Why is power factor important for battery storage?
- Grid operators require BESS plants to hold power factor within a band and often to provide voltage support via reactive power. Power factor sizing determines how much of the inverter kVA must be reserved for kVAr rather than kW.