Power factor is a measure of the efficiency of an electrical system, indicating how effectively electrical power is converted into useful work output. It is defined as the ratio of True Power (real power in kilowatts, kW) to Apparent Power (total power in kilovolt-amperes, kVA). Mathematically, it is expressed as:

$$Power\:factor\:\left(PF\right)=\frac{True\:power\:\left(kW\right)}{Apparent\:power\:\left(kVA\right)}$$

The power factor is a dimensionless quantity, represented as a value between 0 and 1 or as a percentage. A power factor of 1 (or 100%) signifies that all the apparent power is being effectively used as true power. For most shipboard systems, the power factor is typically 0.8 lagging, indicating that the current lags the voltage by an angle θ due to inductive loads.

Reasons to maintain high power factor onboard ship:

• Reduces Equipment Costs: Low power factor increases apparent power (kVA), requiring larger generators, transformers, and distribution systems, thereby increasing costs.
• Minimizes Energy Losses: Low power factor increases current flow, resulting in higher I²R losses and reduced system efficiency.
• Improves Voltage Regulation: A high power factor ensures better voltage stability, which is critical for sensitive equipment.
• Enhances Load Capacity: With a high power factor, existing equipment can handle additional loads, optimizing resources.

Static Capacitors

• Capacitors are connected in parallel with inductive loads.
• These capacitors generate a leading current that offsets the lagging current caused by inductive loads, thereby improving the power factor.
• Advantages: Simple to install, low maintenance, and cost-effective.

Synchronous Condenser

• Overexcited synchronous motors (used as condensers) are connected to the electrical system.
• These machines supply leading reactive power, compensating for lagging power due to inductive loads.
• Advantages: Effective for large systems and improves system stability.

Phase Advancers

• Phase advancers are used to improve the power factor of large induction motors.
• They supply the excitation current required for the motor, reducing lag and improving efficiency.
• Advantages: Reduces load on the supply line and is efficient for high-power applications.

Impact of power factor correction on system efficiency:

• For the same load, corrected power factor decreases current flow, reducing I²R losses in cables and transformers.
• Reduced current and energy losses directly translate into lower operational costs.
• With reduced apparent power requirements, smaller cables, transformers, and generators can be used, saving space and capital costs.
• Corrected power factor ensures stable voltage levels, preventing under-voltage issues for connected equipment.
• By improving power factor, existing systems can accommodate additional loads without overloading equipment.