kilo Volt Amperes (kVA) and What is it?

kVA stands for kilo Volt Amps and is used to refer to the measurement of power in a transformer or from a generator. It is as a result of the product of voltage and power. The kilo Volt Amps is mainly used for the purpose of showing the output capacity in a generator. This is important within buildings to understand the availability of energy coming into the property.

As an Energy Manager we focus on and manage energy through Kilowatts (kW) When this is reviewed over time this equates to Kilowatt Hour (kWh) and this gives us the consumption. kVA is placed second and often overlooked, if we focus on this area there are considerable savings to be made, but if we neglect this area there is significant costs. This is apparent in the larger properties and highlighted in the billing.

We have two areas of power both Actual and Apparent which are explained as follows.

Actual Power

Therefore, we can refer to kW as actual power, it is the amount of power that is converted into an output. kW x Time gives us kWh.

Apparent Power

This is known as Kilovolt Amperes (kVA) this is the measurement of apparent power. It describes the total amount of power being used by a system.

If the power factor is recorded, we then know how we can understand how to convert the kVA to kW because you know the efficiency level of the electrical system in question.

Electrical efficiency is usually expressed as a power factor in between 0 & 1, therefore the closer the power factor is to 1, then the more efficiently the kVA is being converted into actual kilowatts.

The kVA to kW and kW to kVA Formula:

1.      The formula for converting

Apparent power (kVA) x power factor (pf) = actual power (kW)

e.g. 100 kVA x 0.8 = 80 kW

2. The formula for converting kW into kVA is:

Actual power (kW) / power factor (pf) = apparent power (kVA)

e.g. 80kW /0.8 = 100kVA.

Note: We also have Reactive Power is the resultant power in watts of an AC circuit when the current waveform is out of phase with the waveform of the voltage, usually by 90 degrees if the load is purely reactive, and is the result of either capacitive or inductive loads. Which Will be covered within another Article.