Power Generation/Variable Load/Part4

Selecting generating units:

The following must be considered when selecting the number and size of Generating units (Generators):


 * Number and size of units to aproximately fit the annual load curve.


 * Units to be of different capacities to meet load requirements.


 * Atleast 15 - 20% of extra capacity for future expansion should be allowed for.


 * Spare generating capacity must be allowed for to cater for repairs and overhauling of working units without affecting supply of minimum demand.


 * Avoid selecting smaller units to closely fit load curve.

Meeting Load:

The best method to meet load requirements on power station is to Interconnect two different power stations in paralell as follows:

-- Generally thermal & Nuclear power stations.
 * More efficient Plant → Carries Base load( The unvarying load on the load curve ).

-- Generally Hydro, Pumped storage & gas turbine power stations.
 * Less efficient Plant → Carries Peak load ( Various load peak demands on the load curve ).

Careful study of load curves must be undertaken before deciding which type of station will be used for what purpose as this is greatly dependant on enviromental issues and availability of fuel used by a particular power station.