The Global Community for Sustainable Energy Professionals
A minute lecture proposing four different analogies on reactive power:
Did anyone ever ask you what reactive power is? Did you manage to explain? Reactive power is an important aspect of the electrical system, but one that is difficult to grasp. Several analogies can be made to visualise this abstract phenomenon. Of course, none of them are 100% correct, but we hope they will give you inspiration while clarifying the concept to others.
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The reactive power is too difficult to explain! For experienced person, I say that reactive power has no relation with energy (power). It's a misleading quantity (erroneous name). Thus, the commonly known definitions always conduce to impasses in non linear load cases. For the beginners, I think that all these analogies are good to explain simply the reactive power (in linear load).
Reactive power in an AC power system is simply that power which is used to build and colapse magnetic fields in inductive devices such as transformers and motors every half cycle.
This really means that the sum of all magnetic fields (loads) in the consumer grid system must be matched every moment by the size of the magnetic fields in the genetators supplying that grid system.
Doing a simple bench experiment using D.C. where we colapse a magnetic field into a light bulb after the D.C. source has been removed helps the student recognize that "there's power in them thar fields." Realizing then that when A.C. is applied across a coil that builds a magnetic field, we can then realize that as we change polarity with each half cycle of A.C. we must oppose and colapse the previous charged field and rebuild one of the opposite polarity by moving all of the free electrons in the related conductors to a new field polarity. This happens each half cycle, hence work is done in opposition to the previous field on each new half cycle.
Electrical Bob