Below shows the power vector diagram.
The power consists of active, reactive and apparent power
Active power (VI cosØ)
\ Ø |
\ | Reactive Power (VI sinØ)
Active power (P) = V*I*cosØ
Reactive power (S) = V*I*sinØApparent power (Q) = V*I
Here the useful power is the active power and the reactive power is due to the lagging power factor due to the connected loads. This power factor varies with each load and you need a power factor monitoring equipment to check the power factor each time.
To find out the capacitive bank you should know the system power factor (system power factor can be measured by a power factor meter when all the system is connected)
Here, you have 1500 kW load.
Ie, P = 1500
Hence S = 1500 / cosØ
And Q = sqrt(S2 – P2)
To compensate the power to unity, you need to provide “Q” amount of capacitive power.