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.

Effects of Low Power Factor:

• Increased Cost of Generating and Distribution Equipment. At a low power factor, the apparent power (kVA) required for the same true power (kW) increases. This necessitates larger generators, transformers, and distribution equipment, leading to higher capital and maintenance costs.
• Low power factor adversely affects voltage regulation, making it difficult to maintain voltage levels within specified limits. This can lead to instability and improper functioning of sensitive equipment.
• For a given load, a low power factor increases the current flowing through the conductors. This results in greater I²R losses (heat loss due to resistance), reducing overall system efficiency.
• To carry the increased current associated with low power factor, larger conductor sizes are needed, further escalating installation costs.
• At a low power factor, more apparent power (kVA) is consumed for the same true power (kW). This reduces the capacity of existing equipment to handle additional loads.
• Utilities may impose penalties or higher tariffs for operating with a low power factor, as it places additional strain on the power grid.