Power factor correction circuitry

Recently there has been growing interest in power factor correction circuitry. Power factor, which is defined as the ratio of the apparent required power to the actual true power, ultimately affects the circuit s efficiency, thus varying the cost of electricity. It seems that almost all AC-powered equipment now require some form of active power factor correction in order to operate efficiently. Active power factor correction utilizes electronics to force the input current to look like a... 

Polystyrene capacitors have exceptionally low tan S values (< 10 q, making them well suited for frequency-selective circuits in telecommunications equipment. Polymer capacitors are widely used for power-factor correction in fluorescent lighting units, and in start/run circuitry for medium-type electric motors used in washing machines, tumble-dryers and copying machines for example. They are also used in filter circuits to suppress radio frequencies transmitted along main leads. Such interference noise may originate from mechanical switches, furnace controllers and switch mode power supplies it not only spoils radio and television reception but can also cause serious faults in data-processing and computer equipment. 

The electrical supply equipment is the second biggest equipment package after the mechanical equipment. The package includes the transformer/rectifier (T/R) sets and bus bars for providing DC power to the cells, the associated power factor correction equipment and harmonics filtration equipment, and the service transformers and circuitry. This equipment will typically comprise about 15 - 25 % of the cellhouse cost. The cost is heavily influenced by whether or not an electrical substation is included, and by the redundancy requirements for the T/R sets. A plant can choose to have no spare T/R capacity, partial redundancy, or full redundancy. Such cost savings must be weighed against the cost of lost production when a T/R set fails. 

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