Diesel Generators and Power Factors

You can used capacitor on DG set . This only after load the DG set. ensure that PF should be with in the 0.9PF. If you have APFC( automatic power factor corrctor ) system that you should no have problem to monitor the pf of DG set

S.Pathan

Dear,

Fristly the design Power factor of the DG set is 0.8, i.e. capacity of the DG can be used 80%, If you run the DG set on higher power factor then DG set run on more excitation due the more excitation the DG set goes to the Capacitive load when the DG set run capcitve load then current lead to the voltage. This is the losses of power. Then if you want to connect the capacitor when DG set is used, then you can connect the capacitor in manual mode with the DG breaker interlocking.

Mohan Kushwaha

Dear Sir I have a pump, whose nameplate reads that power is 5.5 kW and current is 11.9 A - 415V. Thus the power factor is .643 ( Am I right ? ) We have 25 such pumps. I am using a 250 kVA Prime Power Diesel generator to run all these 25 pumps. Is it ok ? My genset is breakdown 3 times ( once crankshaft failure, twice coolant leakage from cylinder head joint ) Any help will be highly appreciated.

Hi,

As you know the Diesel alternator is designed for 0.8 pf. In case you add capacitor banks & try to improve the pf then the current will be leading since the design is at 0.8 pf.

Therefore you can go upto the maximum of 0.8 pf correction in case the load pf falls . Auto pf relay can be used with the preset of 0.8 pf as the cut off threshold.

What kind of load do you have? There are cases of loads where you can't do much with power factor control or with capacitor bank; the cause is the load wich deforms the sine wave. You may check the harmonics that each load is injecting in the network. Only a linear load doesn't introduces harmonics into the feeding cable. Remember that there are no ideal loads, or capacitor banks, or generators. A capacitor bank could worsen the situation if the low power factor isn't due to the reactive power. Pay attention to details.

We have Power Factor = 0.5PF and we also too much harmonics at our load center. We have Capacitor bank with automactic power factor correction(APFC) . This APFC achive power factor from 0.5PF to 0.9PF on DG set.

We are running Load this type system last 20Years and our DG set is working mechnically & electrically Good . We had give Annual maintenance contract with Our Diesel Generator made only

In inductive load with thyristor control ( AC & DC drive ) always produced more harmonics in the total power system . Till 20Years no problem in our system

Regards