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Reactive power does not do any work, so it is represented as the imaginary axis of the vector diagram. Active power does do work, so it is the real axis. The unit for power is the watt (symbol: W). Apparent power is often expressed in volt-amperes (VA) since it is the product of RMS voltage and RMS current. The unit for reactive power is var ...
The amount of reactive power supplied by a shunt capacitor is proportional to the square of the line voltage, so the capacitor contributes less under low-voltage conditions (frequently caused by the lack of reactive power). This is a serious drawback, as the supply of reactive power by a capacitor drops when it is most needed; [11]
In practice, the prime mover (a power source that drives the generator) is designed for less active power than the generator is capable of (due to the fact that in real life generator always has to deliver some reactive power [2]), so a prime mover limit (a vertical dashed line on the illustration) changes the constraints somewhat (in the ...
In electric power transmission and distribution, volt-ampere reactive (var) is a unit of measurement of reactive power. Reactive power exists in an AC circuit when the current and voltage are not in phase.
In power engineering, the power-flow study, or load-flow study, is a numerical analysis of the flow of electric power in an interconnected system. A power-flow study usually uses simplified notations such as a one-line diagram and per-unit system, and focuses on various aspects of AC power parameters, such as Voltage, voltage angles, real power and reactive power.
Electrical loads consuming alternating current power consume both real power and reactive power. The vector sum of real and reactive power is the complex power, and its magnitude is the apparent power. The presence of reactive power causes the real power to be less than the apparent power, and so, the electric load has a power factor of less ...
Reactive power can be used to compensate the voltage drops, but must be provided closer to the loads than real power needs (this is because reactive power tend to travel badly through the grid). Notice that voltage can be controlled also using transformer taps and voltage regulators .
The latter includes power that is unusable, so a power factor of 1 is desirable. A low power factor would mean that the electricity supplier would effectively supply more energy than the consumer's bill would indicate, and suppliers are allowed to charge for low power factors. Reactive power is the name given to unusable power. It does no work ...