power factor circuit

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    As an electrical engineer in Rawang Power Electrical Consultant Company, your boss assigned your group to design a power factor circuit to improve the low power factor in one terrace house in Taman Maju Jaya, Rawang. The terrace house received a power supply 240V, 50Hz from TNB. The loads in that house consist of : 

    Device , Units ,Active Power ,Power factor
    Florescent Lights ,10 ,40W each , 0.5
    Air-conditioning ,4 ,750W each , 0.7
    CFL Lights ,7 25W each , 0.6

    Your group needs to produce the best proposal on designing a power factor circuit to improve the power factor to 0.98 and verify your design with appropriate simulation program. 
    Compare the current, power factor, apparent power, reactive power and active power consumed before and after the power factor correction exercise.
    Write a brief proposal contains the design and findings.

    the problem is where should i start first, how to calculate total power factor and correct it to 0.98?


    You have the real power (W) for each item.

    You have the power factor for each item.

    Calculate the apparent power (VA) for each item. This is Watts divided by Power factor.

    Add  the Watts (W)  for each item to get the total real power (W).

    Add the apparent power for each item to get the total for apparent power (VA).

    The overall power factor is total real power (W) divided by total apparent power  (VA).

    To get power factor angle take acos of the power factor.

    Reactive power (VAR)  is sin (power factor angle) x apparent power (VA).

    Determine the total reactive power( VAR).

    Determine the apparent power (VA) at 0.98 power factor by dividing the total real power (W) by 0.98

    Determine power factor angle at power factor 0.98 = acos 0.98 = 11.4degrees

    Determine total reactive power (VAR) at 0.98 power factor = total apparent power (VA) x sin 11.4 degrees.

    Amount of compensation required = total VAR uncompensated – total VAR at 0.98 power factor.

    Good luck. Don’t forget to consider what happens of load is only partial rather than full.

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