KVAR Calculator

| Added in Physics

What is KVAR and Why Should You Care?

KVAR, short for kilovolt-ampere reactive, measures the reactive power in an AC electrical system. Think of reactive power as the "inefficient" portion of power - it does not perform useful work but is necessary for maintaining electromagnetic fields in motors and transformers.

Understanding and managing KVAR leads to better energy savings and more efficient energy consumption. This is especially important in commercial and industrial settings where optimizing energy usage results in substantial cost savings.

How to Calculate KVAR

The formula is straightforward:

[\text{KVAR} = \frac{\text{Reactance (Ohms)} \times \text{Current (Amps)}^2}{1000}]

Where:

  • Reactive Power (KVAR) is the measure of reactive power
  • Reactance (Ohms) is the opposition to AC current flow
  • Current (Amps) is the electric current in the circuit

Calculation Example

With a reactance of 30 ohms and current of 120 amps:

[\text{KVAR} = \frac{30 \times 120^2}{1000} = \frac{30 \times 14400}{1000} = \frac{432000}{1000} = 432 \text{ KVAR}]

Summary Table

Reactance (Ohms) Current (Amps) KVAR
30 120 432
20 100 200
50 80 320

Power Factor Improvement

Understanding KVAR helps you:

  • Identify inefficiencies in electrical systems
  • Size capacitor banks for power factor correction
  • Reduce utility power factor penalties
  • Lower overall energy costs

Frequently Asked Questions

KVAR stands for kilovolt-ampere reactive, a unit measuring reactive power in AC electrical systems. Reactive power does not perform useful work but is necessary for maintaining voltage levels in the system.

High reactive power reduces system efficiency, increases energy costs, and can lead to penalties from utilities. Managing KVAR through power factor correction improves efficiency and reduces costs.

Reactance is the opposition to alternating current caused by inductors and capacitors in a circuit. Unlike resistance, reactance causes the current and voltage to be out of phase.

Install capacitor banks for power factor correction, size motors correctly for their loads, and consider using variable frequency drives to reduce reactive power consumption.