Reactive power (kVAR) can be calculated from active power (kW) using the power factor of the electrical system. This calculation is essential for capacitor bank sizing, power factor correction, and electrical system design.
Formula to Calculate kVAR
kVAR = kW x tan(cos−1(Power Factor))
Where:
- kW = Active Power
- Power Factor (PF) = Decimal value (e.g., 0.8, 0.9, 0.95)
- kVAR = Reactive Power
Step-by-Step Calculation
Given:
- Active Power = 100 kW
- Power Factor = 0.80
Step 1: Find the phase angle
Θ = cos−1(0.80) = 36.87∘
Step 2: Calculate tan θ
tan(36.87∘) = 0.75
Step 3: Calculate reactive power
kVAR = 100 x 0.75 = 75 kVAR
Answer: Reactive Power = 75 kVAR
Why Calculate kVAR?
- Size capacitor banks correctly
- Improve power factor
- Reduce reactive power penalties
- Improve system efficiency
- Optimize transformer and generator loading
- Minimize power losses in electrical networks
Calculators
kW to kVA Calculator for Diesel Generators
KW TO KVA CALCULATOR
kVA/kW Ampere (Amp) Chart
Applications
- Industrial power systems
- Electrical distribution networks
- Motor installations
- Transformer sizing
- Power factor correction projects
- Solar and renewable energy systems
- Electrical energy audits