# Power factor correction calculations for power system – MS Excel Spreadsheet

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## Power Factor correction using static capacitor

Calculation formulas as follows:

• Q1 =  I losses + Cu losses
• Q2 = PkW · (Tanφ1 – Tanφ2)
• losses = 2% ·  Str
• Cu losses = USC% · Str
• Q = Q1 + Q2

Where:

• Q1 = Reactive power to be compensated at the terminals of a transformer due to no load and load losses.
• Q2 = Reactive power to be compensated due to total reactive components of lighting, power and mechanical loads.
• Q = Overall reactive power to be compensated to achieve target power factor.
• I losses = Transformer no load losses = Iron core losses.
• Cu losses = Transformer load losses = Copper losses.
• Str = Transformer rating (KVA).
• P = Maximum demand load on the Main distribution board (kW).
• φ1 = Inverse cosine of power factor before compensation.
• φ2 = Inverse cosine of target power factor.
• Usc% = Short circuit percentage impedance voltage of the transformer.

Power Factor Values assumptions before compensation:

• For lighting outlets = 0.96
• For power outlets and receptacles = 0.8
• For motors = 0.8

Inputs = Transformer size + Transformer type + kVA Max. demand load for the whole system + PF before compensation + Target value of PF.

Outputs = Reactive power to be compensated at the terminals of a transformer due to no load and load losses.

• Reactive power to be compensated due to total reactive components of lighting, power and mechanical loads
• Overall reactive power to be compensated to achieve target power factor + circuit breaker size required to protect the capacitor bank.

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1. SUBODH JHA
Aug 19, 2014

THANKS FOR SUCH A GOOD INFORMATION & KNOWLEDGE.

2. Mahmoud Salama
Aug 15, 2014

Many Thanks for publishing this calculation sheet on your reputable site. it gave me much pleasure and confidence to create other sheets to share knowledge and introduce Fast tools.

Aug 10, 2014

Thank you somuch for your various articles on elect engg subsubjects which are extremely helpful for we engineers

Aug 10, 2014

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