What Is Reactive Power ?
"What Is ?"
A synchronous generator, perhaps in its
most correct description, generates electromagnetic waves that travel
along transmission lines that guide the waves to the loads. Unless the loads have special
characteristics, not all of the power in the arriving waves is absorbed. The
power absorbed is referred to as Real power. The power not absorbed is
reflected in waves that travel back to the generator. The power in the reflected waves is the Reactive
Power.
This power represent waste and, therefore , something to be eliminated or
minimized to the extent possible.
The first engineers that had to content with these reflected waves were
those working on the Telegraph
at the turn of the last century. They
discovered that to eliminate the loss of signal strength due to the
reflections, the loads and line
branching had to be impedance “matched” to the oncoming line, and techniques
were developed to do this. These
techniques remain widely used today in the communication industry.
The application of these techniques in Electrical Power Systems to the extent needed to eliminate
reflections is not practical.
Accordingly power system engineers have had to develop techniques to
manage Reactive
Power.