Active power is the average rate at which energy flows from source to load, equal to V x I x cos(phi) in a single-phase sinusoidal circuit and measured in W, kW or MW. It turns motor shafts, heats elements and drives the revenue meter, so generation is dispatched and billed on it. In a balanced three-phase system it equals 1.732 times line voltage times line current times power factor.
Active power's holding at 180 MW but the reactive keeps climbing, call the plant and ask them to back off the excitation.
Also heard as
- real power
- true power
- P
Do not mix it up with
- Apparent power: Apparent power is RMS voltage times RMS current in VA and includes the reactive part that does no net work.
Related terms
Reactive power
Power that surges back and forth between the source and the fields of inductors and capacitors, doing no net work.
Apparent power
Product of RMS voltage and RMS current, the figure transformers, generators and UPS units are rated on.
Power factor
Ratio of active power to apparent power, showing how much of the current drawn does useful work.