The actual amount of power being dissipated or performs the useful work in the circuit is called as active or true or real power. It is measured in watts, practically measured in KW (kilowatts) and MW (megawatts) in power systems.
The average value of the second term in the above derived expression is zero, so the power contributed by this term is zero. The component, which is proportional to VI sin ϕ is called as reactive power, represented by the letter Q.
The complex combination of true or active power and reactive power is called apparent power. Without reference to any phase angle, the product of voltage and current gives the apparent power. The apparent power is useful for rating the power equipment.
Active Power is that which results in active work (propelling the wheel-barrow in forward direction). So active power is solely that work which is done on the wheels of the barrow for the procurement of real (useful) work.
Reactive Power can be reckoned as that which helps to keep the barrow in the lifted position.
The total power which is the Apparent Power (Lifting + Pushing) is that which is applied at the handles
- kW is WORKING POWER (also called Actual Power or Active Power or Real Power). …..It is the power that actually powers the equipment and performs useful work.
- kVAR is REACTIVE POWER ….. It is the power that magnetic equipment (transformer, motor, relay etc.) needs to produce the magnetizing flux.
- kVA is APPARENT POWER…… It is the “vectorial summation” of KVAR and KW .