What is the difference between KV, KVAR, KVA, KW ?

What is the difference between KV, KVAR, KVA, KW ?


  • Kv is called as Kilo Volts or 1000Volts.
  • Voltage is electrical pressure and one half of power….current(A) being the other half.
  • KV - This is a measure of voltage in kilo volts.


  • KVA is called as Kilo Volt Amps or 1000Volt Amps.
  • This is the potential energy that can be given, if it were consumed it would be expressed as Watts(W).
  • Transformers are rated in Volt Amps since they don’t consume power, they can deliver that much so for clarity you d0n’t use Watts however, they both express power.
  • KVA = Apparent Power ( V*I*cos(phi) )


  • KW is called as Kilo Watts or 1000Watts.
  • This is the same as KVA but it is not potential energy.
  • It is kenetic, energy that is doing work. Heaters etc…are all rated in Watts since they are doing work(creating heat, spinning).
  • This is the difference between VA and W. Both are found by multiplying Volts and Amps together, but one is energy available and the other is energy performing work.
  • KW = Active Power square(V^2 + I^2)


  • KVAR is called as Kilo Volt Amps Reactive or 1000Volt Amps Reactive.
  • It is the amount of “imaginary” power in a system. This happens when the voltage and current wave forms are no longer in phase with each other because of inductance\capacitance in an AC system.
  • This one is a tiny less compare to the others. Its tough to type in this explanation but if both Voltage and Amperage wave forms peaked at the same time you would have maximum power because your biggest push and your biggest flow happen at the same time.
  • If your maximum Voltage in your circuit was 100V and your maximum current were 100A, you would have 10,000Watts available.
  • If the exact same system was out of phase so that Voltage peaked when current was only at 50% you would have 5,000W available to consume.
  • The other 5,000Watts would be wasted and expressed as VA. This isn't good because you still pay for reactive power.
  • KVAr = Reactive Power ( V*I*sin(phi) )

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