Both kVA and kW are terms associated with electrical appliances and their power, more specifically. They both denote the power of an appliance and can easily be found on the label of the appliance. They are often confused by users as one and same but there are certain differences between them.
kVA vs kW
The main difference between kVA and kW is that kVA is the apparent power, that is, the total amount of power in use in a system, while kW is the actual power that is being converted into useful output by a system. The kW stands for kilowatt while kVA stands for kilo volt-ampere.
In a 100% efficient system, kVA is equal to kW. But in non-ideal cases, kVA can be converted to kW using certain formulas and determining the power factor, which is a representation of the electrical efficiency of the appliance.
Comparison Table Between kVA and kW
| Parameter of Comparison | kVA | kW |
| Reference | kVA is referred to as the apparent power. | kW is referred to as the actual power. |
| Expansion | kVA stands for kilo volt-ampere. | Kw stands for kilowatt. |
| Concept | kVA is an ideal or theoretical concept. | kW is a practical concept and is equal to Kva only if all the conditions are completely ideal. |
| Definition | kVA is referred to as the total amount of power in use in a system. | kW is the actual power that is being utilised for the functioning of the system. |
| Conversion | kVA can be converted to kW by multiplying it with the power factor of an electrical appliance or system. | kW can be converted to kVA by dividing it with the power factor of an electrical appliance or system. |
What is kVA?
kVA stands for Kilo Volt Ampere. It is an electrical term, often used in connection with electrical appliances. kVA is mainly associated with the power and utility of an electrical appliance or system. It can be easily found on the labels of most of the appliances or electrical systems.
kVA refers to the apparent power of an electrical appliance or system. It is the total amount of power in use in a system. This is easy to find out and is often an ideal concept. Because in practice, a lot of factors reduce the amount of power that is supposed to be utilized by the system.
The actual power output will always be less than as mentioned in the kVA. Being a theoretical concept however, it has great significance in calculations and designing of certain electrical systems. kVA can be easily converted into kW, which is the actual power output and its more practical counterpart by a simple formula. By determining the power factor of an appliance or electrical system, it can be multiplied with the kVA of the system to find out the actual amount of output the system gives or its kW in other words.
What is kW?
kW stands for kilowatt. It is a unit of power. It is a more practical unit as compared to kVA. It has useful applications in ideal as well as non-ideal conditions.
It is the power that is available to do work and produce an output, while kVA is not available at its maximum since a part of it is expended. This unit, kW is an actual measure of how much valid work is done by the electrical appliance.
In a DC circuit, kW is the same as kVA. In an AC circuit, however, the kW is less than kVA and can be converted to the same by taking the power factor into count. This is also based on the rate of inhibition that occurs in the circuit.
Under ideal conditions, kW is the same as kVA. However, in real-life practical applications, this never happens. A part of the energy and power supplied is never utilized. Thus, kW is a measure of how much power can be utilized and converted into useful output with the remaining amount of power available.
Main Differences Between kVA and kW
- Both kVA and kW are units of power and determine how much useful work is done by an electrical appliance or electrical system. However, kVA states the apparent power while kW states the actual power.
- kVA stands for kilo volt-ampere, while kW stands for kilowatt. These are both different units of the same quantity, however, represent slightly different aspects of it.
- Both of them determine the amount of work done by an electrical system and the amount of power output supplied by it. But while kVA is a measure of the theoretical power output of the appliance is ideal conditions, kW is a measure of the actual power output of the system in non-ideal practical conditions, as only a portion of the power is available in this case.
- kVA is a theoretical concept associated with an appliance but kW is a practical concept and a real measure of the power output of an electrical system.
- kVA can be converted to kW by multiplying the power factor with it, while kW can be converted to kVA by dividing it with the power factor.
Conclusion
Both kVA and kW are units of power and determine the power of an electrical appliance. They can both be easily seen on the label on an appliance. Sometimes only one of them is available. But it can easily be converted to the other by taking the power factor into account. The terms mean almost the same and are often used interchangeably. kVA is a measure of the ideal power output of the system while kW is a measure of the practical and actual power output of the system. But with some idea of the right distinction between them, they can be easily distinguished and used appropriately as the situation demands.
References
- https://www.sciencedirect.com/science/article/pii/S1364032114004651
- https://ieeexplore.ieee.org/abstract/document/883137/