# 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. Jordan Araujo
Nov 17, 2016

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2. Hapsari Dewi
Nov 14, 2016

Thank You for the article and the excel spreadsheet

3. SUBODH JHA
Aug 19, 2014

THANKS FOR SUCH A GOOD INFORMATION & KNOWLEDGE.

4. Mahmoud Salama
Aug 15, 2014

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