DP 331 Tutorial 1

DP 331 TUTORIAL QUESTIONS

1

A react eactiion turb turbiine is supp suppllied ied wit with 100 100 cu m of wat water per per secon econd d and and work workss under under a maximum maximum head of 120 m at 350 rpm. Assuming Assuming plant’s plant’s overall efficien efficiency cy of 80% and water density of 1000 kg per cu m, calculate the power in kW.

2

(a) (a)

Calc Calcul ulat atee the the tot total al ener energy gy in kWh kWh whic which h can can be gene genera rate ted d from from a hyd hydro ro powe powerr sta stati tion on having the following data:

(b)

Reservoir area

= 2. 2.5 sq.km.

Capacity

= 5 x 106 m3

 Net  Net Head Head of wate waterr at at the the tur turbi bine ne

= 80 80 m

Turbine efficiency

= 80%

Generator efficiency

= 90%

Find Find by how how many many mete meters rs the the level level of the rese reservo rvoir ir will will fall fall if if a load load of 20,00 20,000 0

kW is supplied for 5 hours.

3

For For a hydr hydro o elec electr tric ic pow power er pla plant nt the the fol follo lowi wing ng annu annual al dat dataa is sup suppl plie ied: d: Annual rain fall

=

1000 mm

Catchment area

=

120 sq.km.

Effective Head

=

250 m

Load factor (λ )

=

40%

Yield factor (k) to allow for run off and evaporation loss k

=

50%

Efficiency of the plant

=

70%

Determ Determine ine the follow following ing::

4

(a)

Average Average power power produce produced d

(b) (b)

Capa Capaci city ty of the the pow power er plan plantt

Calcul Calculate ate the power power that that can can be be devel developed oped from from a HPS HPS havi having ng the follow following ing data: data: Catchment area

=

100 sq. km.

Average rain fall

=

120 cm

evaporation loss

=

20%

Available Head

=

300 m

Plant’s ov overall ef efficiency

=

75%

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5

Determine the power that can be developed from a HPS with the following data: Area of reservoir

=

3 x 108 sq m

Mean Head

=

40 m

Annual average rain fall

=

110cm

Turbine efficiency

=

80%

Generator efficiency

=

85%

Assume that 25% of rain is lost due to evaporation and 4% head is lost in penstock.

6

For a hydro electric power plant the following data is supplied: reservoir area

=

2000 sq.km

capacity

=

2.0 x 109 m3

net head

=

200 m

Load factor (λ )

=

0.8

Yield factor (k) to allow for run off and evaporation loss k

=

25%

Turbine efficiency

=

90%

Generator efficiency

=

95%

If the density of water is taken as 1000 kg/m3 calculate: The change in level of the reservoir if the power station is to supply its rated capacity for 72 h ours.

7

Name various factors to be considered when selecting the site for the hydro power plant. The hydro-electric power station has the following data: Catchment area

300 sq. km.

total plant efficiency

80%

yield factor to allow for run off and evaporation loss load factor

50%

0.5

Plant capacity

20 MW

The dam level was 200 m at the beginning of the month of January and 202 m at the end of  January of the same year. If the dam level is taken as the effective head of the plant and the average daily rainfall in January was 5 mm, find the reservoir area .

8

a)

A power station has a maximum demand of 80 MW and the daily load curve is defined as follows:

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time in hours

0-6

load in MW

40

6-8

8-12

12-14

14-18

18-22

22-24

50

60

50

70

80

40

(i)

Determine the load factor of the power station.

(ii)

What is the load factor of the stand-by generator rated 25 MW that takes up all load in excess of 60 MW.

(b)

In a 60 MW steam power station working at 40% load factor the energy cost is found to be 1.50 shs/kWhr. Calculate the cost of energy if the power station load factor is improved to 50%, and due to increase in energy generation the fuel cost increases the annual generation cost by 6%.

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EE 321 ELCTRICAL POWER SYSTEM TUTORIAL QUESTIONS

1

Stevenson Question 2.15, 2,16, 2.21, and 2.22

2

Stevenson Question 2.15, 2,16, 2.21, and 2.22

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