): In alternating-current power transmission
and distribution, the product of the rms voltage
the apparent power
, multiplied by the sine of the phase angle
between the voltage and the current.
The term VAR was introduced in 1930 by the IEC in Stockholm. The symbol N is usually used for the quantity measured in VARs.
Note 1: Vars represents the power not consumed by a reactive load, i.e., when there is a phase difference between the applied voltage and the current.
Note 2: Only effective power, i.e., the actual power delivered to or consumed by the load, is expressed in watts. Volt-amperes reactive is properly expressed only in volt-amperes, never watts.
Note 3: To maximize transmission efficiency, vars must be minimized by balancing capacitive and inductive loads, or by the addition of an appropriate capacitive or inductive reactance to the load.
Source: from Federal Standard 1037C
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