Aboutcleggsan Expertise All technical areas of Electronics Engineering.
Experience BSEE, MBA, Design, R&D, University Research.
Senior Life Member of IEEE. Life Fellow of AES.
Organizations IEEE, Consumer Electronics Society, Audio Engineering Society.
Broad teaching experience; work experience mostly in consumer electronics and conversion from analog to digital technologies. Pioneer in digital audio at all levels.
Question what is exactly active and reactive power?
in what context are they referred to in transmission lines and motors/generators?
Answer Reactive power is current through times voltage across reactive elements in the circuit; these are capacitors which store energy in the electric field between the plates and inductors which store energy in the magnetic field around the coil. Resistance, on the other hand, is real power because the voltage times the current is real power which is dissipated in heat.
Any circuit having capacitance and inductance in the circuit will have a voltage/current leading or following angle. This give rise to reactive power and is referred to as providing a power factor or pf less than 1.0. PF is the cosine of the angle between current and voltage.
Motors are often very inductive in nature due to the heavy magnetic windings; many motors employ capacitors in the starting circuits to offset the inductance within their windings.
Power transmission lines don't like reactive power because while the extra reactive currents are not using any power at the end of the line, the currents, nonetheless, travel back and forth on the line between the generating plant and the load and the line losses amount to significant losses in the lines.
You can google for many good lectures on this subject for further understanding.
