Why power factor of a Diesel Genset is assumed 0.8 in all calculations?

Question

Why it is suggested not to improve the power factor of DG from 0.8 to 0.99?

Answer 1

because of diesel engine cent percent efficiency is not achieved due to various mechanical losses.

Answer 2

0.80 is a reasonable, real world power factor for your calculations.  If you use 0.99 and it is worse, you risk damaging the generator.  

Performing all your calculations with 0.80 gives you extra cushion if the PF is actually better.

It is not practical (economical) to have capacitors switching on and off to track the load connected to the generator.

Answer 3

.8 is a very practical power factor.  improvement to .99 will not be cost effective.