Glossary · Energy and utilities automation
Power-factor correction
Also known as: Reactive power compensation, PFC
German: Blindleistungskompensation
In electrical engineering, power-factor correction is the reduction of reactive power drawn from the supply, typically by installing capacitors or active compensators close to inductive loads, so that the power factor approaches 1.
- Energy
In one sentence
Power-factor correction reduces the reactive power drawn from the grid, usually with capacitor banks or active compensators, raising the power factor.
Example
An automatic capacitor bank with detuning reactors switches steps in and out to keep the plant's power factor above 0.95.
How it applies
- Engineering: Correction can be central (automatic capacitor banks at the main distribution), group or individual (at a motor). With harmonics present, detuned or active systems are used to avoid resonance.
- Operation: Controllers switch capacitor steps according to measured reactive power; monitoring shows whether the target is reached.
- Maintenance: Capacitors age and must be inspected; after disconnection they can hold a dangerous charge until discharged. This is Stored energy that maintenance procedures must address.
- Documentation: The documentation should cover discharge times, warning labels, inspection intervals and settings. Machine documentation may state whether individual compensation is included.
Reactive power compensation vs. active PFC in power supplies
In plant electrical systems, the term usually means reactive power compensation with capacitor banks. In electronic power supplies, active PFC is a circuit stage that shapes the input current to reduce harmonics. Both raise the power factor but work differently.