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# Power Factor (PF) Correction Calculations for Power System

### Power Factor correction using static capacitor

Calculation formulas as follows:

• Q1 = I losses + Cu losses

• Q2 = PkW · (Tanφ1 – Tanφ2)

• I 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.