Diesel Generator Power Factor

Yes. u can use cap bank but before using it u should know ur reactive power requirements. Also while selecting cap bank cost factor is also imp. U must go for Economical power factor cal . Refer V. K. Mehta's Electrical Power System, S. Chand Publication

Yes, this can be done.

The best way to do it will depend on the particulars of your installation. One way is to provide power factor correction capacitors to each of the larger motors. Another way is to provide a bank of capacitors, switched in or out according to the total of motor loads to be corrected.

Some helpful data would include a list of motors with kw or hp for each, the system voltage, and some sample readings of the power factor you are actually experiencing.

U can use this data ...Motor rated output Capacitor rating

2.2 KW (3 HP) 1 KVAR

3.7 KW (5 HP) 2 KVAR

5.5 KW (7.5 HP) 3 KVAR

7.5 KW (10 HP) 4 KVAR

The value depends on speed too not only on hp. Try to down load from a capacitor or motor manufacturer

This has been covered earlier also in this forum.

- You do not improve the pf of the generator. You improve the pf of the load and thereby improving the generator performance.

- Thou shouldn't attemp unity pf, stop just short of it, because just by chance the overunity condition leading pf will cause a bit of unstability. No idea about DG, but it is a bit damgerous in big ones.

- Find out the pfs of the load and depending on the size and $ you are ready to spend, go for bank or apfc.

- Please remember there is no hard and fast rule relating load to pf (except incandescant lamps or heaters that are any way almost purely resistive) motor pf widely vary depending on load.

- If you have large generating capacity go for APFC, else based on the pf sample put a bank.

- remember not to overshoot the engine capacity (DG are usually rated at 0.8pf say 1000KVA that means it can give only 800KW, do not assume that at unity pf it will give out 1000KW)

Very Good Stuff So Far,

As far as hte Alternator is concerned you need to control the PF of the Load Below Unity. Once the PF Reaches Unity the Control System of Alternator ( AVR ) Malfunctions & raises the Instability of Voltage.

You can have two Options of connecting the capacitor -

Use Capacitor Banks with Auto PF Controller - This will control the PF to the Preset Value by Switching On & Switching OFF the Capacitors depending upon the Load Amp & Load PF.

Secondly you can have localised Capacitors installed between the Motor Starter & the Motor- This capacitor will come in Circuit when you start the motor, Otherwise this will be disconnected from the system.

Please remember - The Capacitors should not be connected to the Alternator When the Alternator is running on No Load, This will Make AVR of the Alternator to Malfunction & will work in Instable Zone.

thanks for responding.

are their any chances of reduction in diesel consumption and how much percentage

Minimal
What is your actual power-factor (uncompensated?)
The reactive power also called imaginary power is acually imaginary power. The Engine does not supply it. It is only what is exchanged between various line components.
While exchanging, it creates certain additional line losses, that is the only thing you can save.
In case of short lines, with proper cabling (size), the cable resistance will be low enough to make the extra I²R loss negligible.