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When p is negative, power is being sent to source. For a R, power is consumed. For a L or C, power flows between source and device. For a RL or RC, these two relationships are combined. Resistor consumes and reactive device stores/sends power to source.
There are two main problems associated with low power factor (or the presence of reactive power) in a load: The reactive component of current, I × sinφ , causes unwanted voltage drop that affects the regulation at the load.
When the reactive power supplied is greater than the reactive power consumed, the excess reactive power can be considered as negative reactive power. In power systems, negative reactive power is often associated with capacitive loads or devices that generate reactive power.
Active power is useful power that does some real work in an AC circuit, whereas reactive power is non-useful power that flows back and forth (in both directions from source to load) but produces electric or magnetic flux.
In the negative half of the voltage waveform between 180 o and 270 o, there is a negative voltage and positive current indicating a negative power. This negative power indicates that the coil is returning the stored electrical energy back to the supply.
The amount of reactive power present in an AC circuit will depend upon the phase shift or phase angle between the voltage and the current and just like active power, reactive power is positive when it is “supplied” and negative when it is “consumed”.
For capacitive loads (e.g. capacitors), the phase shift angle is negative, as the reactive power leads the active power. In this case, the formula is Q = -S × sin(φ)
If you have negative reactive power it means that some component is changing the phase of the voltage and current, in this case in a capacitive manner (current leads voltage). This is because the impedance of a capacitor is 1 sc => 1 jwc => −j 1 wc 1 s c => 1 j w c => − j 1 w c, notice the -j factor. Your Answer.
Power merely absorbed and returned in load due to its reactive properties is referred to as reactive power. Reactive power is symbolized by the letter Q and is measured in the unit of Volt-Amps-Reactive (VAR).
Reactive power is measured as the maximum of the pulsating power over a cycle. It can be positive or negative, depending on whether current peaks before or after voltage. By convention, reactive power, like real power, is positive when it is “supplied” and negative when it is “consumed”.