Power Plant Engineering

8. Load Duration Curve
It is the curve for a plant showing the total time within a specified period, during which the load
equaled or exceeded the values shown.
9. Dump Power
This term is used in hydro plants and it shows the power in excess of the load requirements and
it is made available by surplus water.
10. Firm Power
It is the power, which should always be available even under emergency conditions.
11. Prime Power
It is power, may be mechanical, hydraulic or thermal that is always available for conversion into
electric power.
12. Cold Reserve
It is that reserve generating capacity which is not in operation but can be made available for
service.

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POWER PLANT ENGINEERING
13. Hot Reserve
It is that reserve generating capacity which is in operation but not in service.
14. Spinning Reserve
It is that reserve generating capacity which is connected to the bus and is ready to take the load.
15. Plant Use Factor
This is a modification of Plant Capacity factor in that only the actual number of hours that the
plant was in operation is used. Thus Annual Plant Use factor is,
= (Annual kWh produced) / [Plant capacity (kW) × number of hours of plant operation]
3.2 FACTOR EFFECTING POWER PLANT DESIGN
Following are the factor effecting while designing a power plant.
(1) Location of power plant
(2) Availability of water in power plant
(3) Availability of labour nearer to power plant
(4) Land cost of power plant
(5) Low operating cost
(6) Low maintenance cost
(7) Low cost of energy generation
(8) Low capital cost
3.3 EFFECT OF POWER PLANT TYPE ON COSTS
The cost of a power plant depends upon, when a new power plant is to set up or an existing plant
is to be replaced or plant to be extended. The cost analysis includes