The power factor of a industrial unit is expected to vary along the time. So, you only can get typical values and, potentially, the highest and lowest values of this parameter. To acquire information about the PF, you should connect and energy analiser with recording capacity. Then, you shoul analise the obtained data in typical days of the industrial factory. The capacitor bank should be sized taking into consideration technical and economical aspects. You should compensate the part of reative power that implies costs.

Power factor of factory is not remains constant, as the main machine used for drive(for mechanical power) are induction motors. The power factor of induction motors are varies considerably(.6 lag to .85lag), for the load variation from noload to full load. Yet you can buy any value approximate value, from market to improve the power factor, and will work..

Hi Mohammed Abdulla,

Power factor of a load center, which has rotating machines will vary with time. We have done a case study and compensating the load reactive power of an Engineering faculty. You can refer to that paper. Hope you will find it useful.

  https://www.researchgate.net/publication/263467819_Design_of_a_Dynamic_Reactive_Power_Compensator_%28DRPC%29_to_Improve_the_Power_Factor_of_a_Load_Center

Conference Paper Design of a Dynamic Reactive Power Compensator (DRPC) to Imp...

Mr. Paulo Moisés Costa, Mr. Bhupendra Desai and Mr. Arunprasanth Sakthivel thanks alot