Automatic Power Factor Control

[seminar class]

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Automatic Power Factor Control
Objective of the Project Work
 To Design a Control Panel Which Will Provide a Constant Power Factor When Plant Load is Constantly Changing, resulting in the need for varying amounts of reactive power.
Scope of Work
• Reduce Power Bill
• Reduce I^2 R Losses In Conductor
• Reduce Loading On Transformers
• Improves Voltage Drop
• Avoid Penalty For Low Power Factor
• Optimise the Capacity By Reducing the Maximum Demand
• Avail Incentives By Maintaining Higher Power Factor
Methodology
• An intelligent power factor correction scheme is presented for three phase low power factor loads.
• This new scheme is able to perform individual phase sensing of parameters by monitoring at all times to sense a change in system parameters and affects individual phase correction by applying the exact amount of reactive components needed for each phase, and can also reduce negative sequence current caused by the load to improve system balance. An optimization criterion is used for the proper calculation of reactive power steps in a power compensation installation of capacitor banks. The criterion is enabled by sampling measurements performed on the electrical plant examined within specific interval of time.
• The scheme involves the application of bank of capacitors controlled by a micro-controller to balance the phases and correct the power factor to higher values.
• Applying this scheme can improve the performance of many industrial plants since it is capable of blocking the negative sequence currents, thus it can eliminate phase unbalance and improve system voltage whilst, and at the same time the power factor can be improved up to desired values.
• Many power industries can benefit from this scheme because of its low cost.
Work Carried Out
• Interested to boost up=90% ,Power Factor2=90%
• Power Factor=KW / KVA
• Cosq = kW / kVA
• q = Cos-1 (PF1)
• q = Cos-1 (75%) =41.41
• The Reactive Power was about:
• tanq = kVAR / kW
• kVAR = kW x tanq
• kVAR = 110 kW x tan (41.41) = 97.01 kVAR
• If the Power Factor were increased to 90%, the Reactive Power would be about:
• Cosq = kW / kVA
• q = Cos-1 (PF2) Power Factor1=75%
• Actual Power=110 kw
• Interested to boost up=90% ,Power Factor2=90%
• Power Factor=KW / KVA
• Cosq = kW / kVA
• q = Cos-1 (PF1)
• q = Cos-1 (75%) =41.41
• q = Cos-1 (90%) = 25.84
• kVAR = kW x tanq
• kVAR = 110 kW x tan (25.84) = 53.27 kVAR
• Thus, the amount of capacitance required to boost power factor from 75% to 90% :
• 97.01 kVAR – 53.27 kVAR = 43.74 kVAR
• So I recommended 50 KVAR Capacitor Bank to Design the Control Panel.
Conclusion
→ By observing all aspects of the power factor it is clear that power factor is the most significant part for the utility Company as well as for the consumer. Utility company rid of from the power losses while the consumer free from low power factor penalty charges.
→ By installing suitably sized power capacitors into the circuit the Power Factor is improved and the value becomes nearer to 0.9 to 0.95 thus minimising line losses and improving the efficiency of a plant