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What is the difference between KVR , KW and KVA?

Question asked by therealabdo in #Electrical #Electronics on Jun 1, 2010
therealabdo
therealabdo 路 Jun 1, 2010
Rank D3 - MASTER

I am countering a problem facing KVR in power systems I just to know what makes it different to KVA and KW?

Posted in: #Electrical #Electronics
lal
lal 路 Jun 2, 2010
Rank A3 - PRO
An electric circuit, for its working consumes energy. And energy consumed per unit time is what we call power.

The total power consumed is represented as KVA (kilo volt ampere). But in this total power a part only does the useful work (assuming my load is not purely resistive 馃榾). The useful power here is called active power, ie KW. The remaining component, the one which do nothing useful is called reactive power or KVR.

We can represent these three as the sides of a right triangle. Total power as the hypotnuse, active power as the cosine component and the other as the sine component. The angle between the active power and total power is the phase angle between current and voltage.
lal
lal 路 Jun 2, 2010
Rank A3 - PRO
'Due to some network problems, i posted the same thing twice!'

If you are considering a purely resistive load, the current and voltage would be in phase. In such a situation the total power cosumed (KVA) would be equal to active power (KW). There is no reactive power (KVR).
lal
lal 路 Jun 2, 2010
Rank A3 - PRO
So i guess it is clear that the phase angle has a role in deciding the active and reactive power components. Since we are interested in active power, we need to increase it. For the same, by some means we decrease the phase difference between current and voltage to the lowest possible value. An example, if your load is inductive, the current lags the voltage by some angle. To compensate this we shall introduce a capacitor in series.
therealabdo
therealabdo 路 Jun 2, 2010
Rank D3 - MASTER
thank you very much it was really useful 馃榿
Kaustubh Katdare
Kaustubh Katdare 路 Feb 1, 2020
Rank A1 - PRO

The KVA, which should actually be written as kVA (where k stands for kilo) is typically referred as kW (kilowatt). This is the unit that is used to rate most of the electrical equipments we use at home.聽

The actual electric power we receive at home is can be divided into two main types: the kW and kVAR aka Kilovolt-Ampere Reactive. The former stands for the "real" or actual power. The kVAR on the other hand stands for the reactive power. Lal has offered a good explanation above.聽

Just to understand it better - active power is the one that actually gets converted into light, heat and sound.

The reactive power, on the other hand is the one that produces magnetic fields that can rotate the shaft of electric motor; and is dependent on the power factor.聽

Ramya Bhandaru
Ramya Bhandaru 路 Feb 3, 2020
Rank D2 - MASTER

kVA is kilo Volt Amps, and is found by measuring the voltage and current separately, and then multiplying them together. It is the measure of 鈥渁pparent power鈥.

kW is kilo Watts, and is found by measuring the voltage and current simultaneously, and multiplying them point by point in phase with each other. It is the measure of 鈥渁ctual power鈥 or 鈥渦seful power鈥.

Venkat Sai Nakkina
Venkat Sai Nakkina 路 Feb 3, 2020
Rank C3 - EXPERT

he KVA, which should actually be written as kVA (where k stands for kilo) is typically referred as kW (kilowatt). This is the unit that is used to rate most of the electrical equipments we use at home.聽

The actual electric power we receive at home is can be divided into two main types: the kW and kVAR aka Kilovolt-Ampere Reactive. The former stands for the "real" or actual power. The kVAR on the other hand stands for the reactive power. Lal has offered a good explanation above.聽

Just to understand it better - active power is the one that actually gets converted into light, heat and sound.

The reactive power, on the other hand is the one that produces magnetic fields that can rotate the shaft of electric motor; and is dependent on the power factor.聽

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