The difference between kVA and kVAR is pretty simple. “kVA” is the unit of apparent power whereas “kVAR” is the unit of reactive power. Before getting into the topic, we recommend you to understand apparent power and reactive power better, by reading this: Real, Reactive, Complex, and Apparent power. Now, let us compare both of them side-by-side to understand them better.
Difference between kVA and kVAR
| kVA | kVAR |
|---|---|
| kVA stands for kilo-volt-ampere | kVAR stands for Kilo-Volt-Amperes Reactive |
| kVA is basically the amount of power that alternators, transformers, and UPS are capable of delivering the load connected to them. | kVAR is the measure of reactive power required by inductive loads such as induction motors, induction furnaces, etc. |
| kVA is independent of the power factor. | kVAR is inversely proportional to the power factor. |
| Alternators, transformers, inverters, UPS, etc are rated in kVA. | Power factor correction capacitors are rated in kVAR. |
Calculation of kVA
Single-phase kVA
For single-phase, kVA can be calculated using the following formula.
kVA = (Voltage X Current)/1000
Three-phase kVA
For three-phase, kVA can be calculated using the following formula.
Three-phase kVA if line to line voltage is known,
kVA = (√3 X Voltage X Current )/1000 = (1.732 X Voltage X Current)/1000
Three-phase kVA if phase to phase voltage is known,
kVA = (3 X Voltage X Current)/1000
Calculation of kVA
Single-phase kVA
For single-phase, kVA can be calculated using the following formula.
kVA = (Voltage X Current)/1000
Three-phase kVA
For three-phase, kVA can be calculated using the following formula.
Three-phase kVA if line to line voltage is known,
kVA = (√3 X Voltage X Current )/1000 = (1.732 X Voltage X Current)/1000
Three-phase kVA if phase to phase voltage is known,
kVA = (3 X Voltage X Current)/1000
Calculation of kVAR – True Power
Single phase kVAR,
For single-phase, kVAR can be calculated using the following formula.
Single-phase – kVAR = (Voltage X Current X (1-Power factor))/1000
Three-phase kilowatts
For three-phase, kVAR can be calculated using the following formula.
Three-phase kVAR if line to line voltage is known,
kW = (√3 X Voltage X Current X (1-Power factor))/1000
= (1.732 X Voltage X Current X (1-Power factor))/1000
Three-phase kVAR if phase to phase voltage is known,
kW = (3 X Voltage X Current X (1-Power factor))/1000
References
- Ewald Fuchs; Mohammad A. S. Masoum (14 July 2015). Power Quality in Power Systems and Electrical Machines
- Differences between kW and kVA