SMPS Power plant

Power plant basic concepts:

Power plant is equipment, which gives uninterrupted DC power supply to the telecommunication systems. Because telecommunication systems require electrical energy for

(a)  Conversion of speech signals to electrical signals  

(b)  For operating switching, transmission equipments

Need of D.C. Power supply

• Harmonics of A.C may affect the speech signals.
• Relays used in telecom systems are more sensitive to D.C than A.C
• Transistors and I.C.s etc. being unidirectional devices, the use of D.C has become necessary.
• Arranging standby source to A.C is difficult compare to D.C for which secondary cells can be used as S/B source.
• Not hazardous to human life.

Sources of power:

Telecommunication systems need uninterrupted power supply round the clock and throughout the year. For any uninterrupted power supply system, two sources are required.

1.    Normal or Main source-Main Source is D.C derived from commercial   source.

2.    Secondary or standby source- Secondary cells

By name we can define “Normal source is one which supplies power to the load round the clock” and “secondary source is one which supplies power to the load only during the absence of power from normal source”.

“Hence it is a must to convert AC from commercial mains to D.C.”

A.C to D.C conversions:

Previously M.G (Motor-Generator) sets were used for A.C to D.C conversion.

In this A.C motor rotates on commercial A.C. supply. To the shaft of this AC motor, D.C. Generator will be coupled which generates D.C. Now a days static rectifiers using static electronic components like metal or diode rectifiers are used.