Start with the load profile, not the capacitor rating
Power factor correction is often discussed as an equipment purchase. A better starting point is to understand when reactive demand occurs, how quickly the load changes and what harmonic-producing equipment is connected.
Information worth collecting
- Recent utility bills and interval-demand information where available.
- Transformer, major motor, drive and existing capacitor-bank details.
- Power factor and demand measurements across representative operating periods.
- Harmonic measurements when variable-speed drives, rectifiers or other non-linear loads are significant.
Why harmonics matter
Capacitors interact with the impedance of the electrical system. Adding capacitance without considering harmonic conditions can increase stress or create resonance. Detuned or filtered arrangements may be appropriate in some systems, but selection should follow measurement and calculation.
A practical review sequence
- Confirm the commercial objective and utility billing mechanism.
- Measure demand, power factor and harmonic conditions.
- Review the existing correction equipment and switching behaviour.
- Model suitable corrective options and protection requirements.
- Verify performance after commissioning.