2.
(a) Explain the meaning of the term power factor correction.
(b) State TWO advantages of power factor correction.(4)
(c) Explain, with the aid of a circuit diagram, how power factor correction can be effected in a three phase circuit using capacitors.(4)
(d) Explain ONE method other than the use of capacitors by means of which power factor correction may be effected.(4)
Reference Answer
### (a) Meaning of Power Factor Correction **Power Factor (PF)** is the ratio of True Power (kW), which performs useful work, to the Apparent Power (kVA), which is the total power supplied by the source. It is also the cosine of the phase angle (φ) between the voltage and current waveforms in an AC circuit. $$ \text{Power Factor (PF)} = \frac{\text{True Power (kW)}}{\text{Apparent Power (kVA)}} = \cos(\phi) $$ In marine electrical systems, a significant portion of the load consists of induction motors, transformers, and fluorescent lighting ballasts. These are **inductive loads**, which require a magnetic field to operate. This causes the current waveform to lag behind the voltage waveform, resulting in a **lagging power factor** (less than 1.0).
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