1) in
how many groups the total cost of electrical energy generated may be divided ?
ANS :
The cost of
generating electrical energy can be broadly divided into three parts , e.g,
i)
Fixed cost
ii)
Semi fixed cost and
iii)
Running or operating cost
2) what
do you mean by “ fixed cost “ , “ semi fixed cost “ and “ running cost “ ?
ANS :
i)
Fixed cost means the standing cost
which depends on the installed capacity of the generating station and is
independent of the maximum demand and the energy output .
ii)
Semi fixed cost means the standing
cost which depends upon the maximum demand but is independent of energy
produced .
iii)
Running cost means the operating cost
which depends upon the number of units of electrical energy generated.
3) what
items constitute the fixed cost , semi fixed cost and running cost of
generation of electrical energy ?
ANS :
The fixed cost
constitutes the annual cost of central organization of the plant , interest on
the capital cost of land and salaries of high officials .
The semi fixed cost
constitutes the annual interest and depreciation on the capital cost of the
generating plant , transmission & distribution networks ,building and other
civil engineering works , all types of
taxes and insurance charges , salaries of management and clerical staff and
yearly compensation given to the workers .
The running cost
constitutes the annual cost of fuel , lubricating oil , water , maintenance and
repair cost of equipment and wages and salaries of operational and maintenance
staff and supervisory staff .
4) what
do ypu mean by “ depreciation “ and “ annual depreciation cost “ of an electric
power plant ? what are the different methods commonly used to determine the depreciation cost ?
ANS :
Depreciation as
applied to power plant is the result of deterioration due to some physical
action , e.g, wear and tear , decay or corrosion an also lack of adaptation to
function caused by obsolescence and inadequacy .
Annual depreciation
cost means a certain amount set aside annually to produce a sufficient sum at
the end of the probable life for replacing the plant and machinery by new ones
which depends upon the type and make of such equipments .
The methods for
determining the depreciation cost are
i)
Straight line method
ii)
Diminishing value method ,
iii)
Sinking fund method .
5) what
is meant by load curve ?
ANS :
Load curve is the
graph of load demands on a system plotted against time in hours .
6) what
information gives the load curve ?
ANS :
Load curve gives the
following informations :
i)
It determines the size and number of
units required for a system.
ii)
The variation of load during the
different hours of the day .
iii)
The maximum demand can be obtained
from the peak of the curve .
iv)
It gives the load factor of the area
in which it is connected .
7) what
is load duration curve ?
ANS :
The load duration
curve is the graph showing the duration of a particular demand or load with the
loads plotted against the number of hours of the percentage of the period for
which it exists in descending order of magnitudes . this curve is useful in calculating
the total requirements of energy to be produced , the load factor , the plant
capacity factor and the plant use factor .
8) what
is integrated load duration curve ?
ANS :
The integrated load
duration curve is the graph showing the total number of units generated for the
given demand with the demand in KW or MW plotted as ordinate against the units
generated as the abscissa .
9) what
do you mean by “ mass curve “?
ANS :
The mass curve is the
graph showing the total energy consumed by the load upto a particular time in a
day with the KWh plotted as ordinate and time
as abscissa.
10)
what do you mean by connected load ?
ANS :
The connected load on
any system is the combined ratings of all the apparatus i.e, total loads on
consumer’s premises which are connected to the system .
11)
what is average demand ?
ANS :
The average demand is
the sum of all the demands divide by the total time .
12)
what do you mean by maximum demand ?
ANS :
Maximum demand of an
installation is the greatest of all the demands that have occurred during a
given period of time say 30 minutes or 60 minutes .
13)
what is load factor ?
ANS :
The ratio of the
average demand to the maximum demand is known as the load factor .
Load factor (L.F) = (
average demand / maximum demand ).
14) the
maximum demand of a consumer is 80 KW and his daily energy consumption is 1200
units . what is his load factor ?
ANS :
L.F. = 1200 / ( 24 x
80 ) = 62.5 %
15) what
is demand factor ?
ANS :
The ratio of the
maximum demand of the power to the total connected load of any system is known
as demand factor
Demand factor =
maximum demand / connected load .
16)
what is diversity factor ?
ANS :
The ratio of the sum
of the maximum demands of different consumers to the maximum demand of the
whole system is termed as the diversity factor .
Diversity factor
(D.F) = ( sum of maximum demands of consumers / maximum demand on the system ).
17) how
can a high diversity factor be obtained ?
ANS :
A high diversity
factor can be obtained by
i)
Giving incentives to mainly consumers
for using electricity in the night or light load periods .
ii)
Using daily light saving,
iii)
Staggering the office timings ,
iv)
Having different time zones in the
country ,
v)
Having two part tariff in which the
consumer has to pay an account for maximum demand plus a charge for each unit
of energy consumed .
18) why
is the load factor of a supply system improved by an increase in diversity
factor ?
ANS :
Since the value of
the maximum demand on the power system becomes less for greater value of the
diversity factor of given consumers , therefore the load factor will be
improved by an increase in diversity factor as a result of which a power
station of given installed capacity will be in a position to supply more
numbers of consumers .
19)
what is the effect of higher diversity factor on the cost per unit generated ?
ANS :
Diversity factor has
the direct effect on the fixed charges of unit generated . greater the value of
the diversity factor , less will be the value of the fixed charges per unit
generated .
20)
what is coincidence factor ?
ANS :
Coincidence factor is
the reciprocal of the diversity factor which is always less than unity .
21)
what is the capacity or plant factor ?
ANS :
The plant factor of a
generating station is defined as the ratio of the average load on the
generators to the total rated capacity of the station .
22)
what is utilization factor ?
ANS :
The ratio of the
maximum demand on the power station to the rated capacity of the power station
is known as utilization factor .
23)
what do you mean by “ plant use factor “ ?
ANS :
Plant use factor is
the ratio of actual energy generated during a given period to the product of
rated capacity of the plant and the number of operating hours during the period
, it is also known as plant operating factor .
24)
what is the effect of load factor and diversity factor on the cost of power
generation ?
ANS :
As the values of load
factor and diversity factor increases
the overall cost per unit generation decreases .
25)
which factors are considered in deciding the number of generators , their sizes
and preparing the operating schedule of a power station ?
ANS :
Load curves ,
diversity factor , demand factor and maintenance facility are considered .
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