Balancing Reservoirs

7/27/2019 Balancing Reservoirs

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BALANCING RESERVOIR

PRESENTED BY-YOGESH KUMAR

ENROLL. NO-12512030

M.TECH(AHES)


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1. Introduction

2. Reservoir and its types.

-Service reservoir

-Balancing Reservoir

3. Purpose of Balancing Reservoir.4. Dependency of Balancing Reservoir.

5. How to fix capacity of Balancing Reservoir.

6. Mass Curve Method.

7. Steps required for Mass Curve MethoD8. Examples for Mass Curve Method.

10. Precautions needed during construction ofBalancing Reservoir.

11. Conclusion.


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Reservoir are the most important and expensive

elements in any hydro power plant.

So, one needs to optimize its design (or capacity)

carefully ,

to avoid the future problems.


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Service Reservoir-

When supply from the source is not continuousfor all the 24 hours ,then supply from the source isstored in a storage reservoir (whenever it is

available) and then supplied to the consumersaccording to the schedule.

Balancing Reservoir-

When the supply from the source is continuousfor all the 24 hours, then during the lean demand

period excess supply from the source is stored in thestorage reservoir and during peak demand period ,water from this source as well as from the storagereservoir is used to meet the required demand.


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The quantity of water required to be stored in thereservoir for equalising or balancing fluctuating

demand against constant supply is known as the

balancing reservoir.


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The main purpose is to store the water during offpeak hours to supply the same during peak hours and

so meeting variable power demand.


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Water Supply Fluctuation

- Seasonal fluctuation

Demand Fluctuation

-Seasonal

-Daily

-Hourly

Effect of flow fluctuations on system design

-Size of balancing reservoirs


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Variable supply

Variable demand

Analyze historic record to search for worst

case conditionsUse same Mass Balance analysis

Include variable demand analysis

It must be designed for daily or hourlyfluctuations.


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Prepare mass inflow curve:

- for all 24 hours for typical days.

(maximum , average and minimum)

Prepare mass curve for demand accordingly.

Superimpose both curve on the same scale.

Take the max difference between demand andsupply discharge as the capacity of the balancing

reservoir


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Available discharge (during lean season) = 5 m^3/s

Available Head = 110m Overall Efficiency = 0.8

Demand Required:-

Hours (Demand)Load(MW)

0-8 1

8-10 2

10-15 5

15-21 10

21-24 1.2


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Hour (Demand)

Load(MW)

Discharge

(m3/s)

Discharge

(m3)

Cumulative

demanddischarge

(m3)

0-8 1 1.158 33350 33350

8-10 2 2.32 16680 50030

10-15 5 5.80 104400 154430

15-21 10 11.58 250210 404640

21-24 1.2 1.4 15120 419760


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Available discharge (during lean season) = 5 m^3/s

i.e. = 18000m^3/hr

Hour(hr) Available

discharge(m3)

Cumulative available

discharge(m3)

Cumulative

demand(m3)

0-8 144000 144000 33350

8-10 36000 180000 50030

10-15 90000 270000 154430

15-21 108000 378000 404640

21-24 54000 432000 419760


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0

50000

100000

150000

200000

250000

300000

350000

400000

450000

0 5 10 15 20 25 30

CUMULATIVE

DEMAND (m3)

AVAILABLE CUMULATIVE

DISCHARGE (m3)

TIME (HOURS)

DISCHARGEVOLUME(m3)

Determination of reservoircapacity


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Calculation for Reservoir Capacity

From the table ,

during 8-10 hours ,

Required Demand = 50030 cubic meter

But, actual available = 180000 cubic meter

Therefore ,

required reservoir volume = 180000 - 50030= 129970 cubicmeter


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Inner surface of Balancing Reservoir being in contact

with water should be lined to prevent seepage loss.

Spilling arrangements should be there.

Some preventive measures in form of excluder and

desilting

chamber are used to avoid the problem of silt .

Location of balancing reservoir.


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Used in isolated type hydro power plant.

Capacity(or size) of balancing reservoir depends on :

-variable supply and variable demand.

But economic comparison is also necessary to

determine optimum storage capacity by adding cost

of reservoirs and pipelines.


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http://www.thewatertreatments.com/water/service-

reservoirs-function-type-volume

http://nptel.iitm.ac.in/courses/Webcourse-contents/IIT-

KANPUR/wasteWater/Lecture%2014.htm

http://nptel.iitm.ac.in/courses/Webcourse-contents/IIT-KANPUR/wasteWater/mass%20curve%20method.htm

o5-reservoirs:-

http://www.slidefinder.net/r/reservoirs_balancing_supply_demand/23826463

Irrigation and water power engineering(B.C.Punmia &

P.B.Basi Lal).


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THANK YOU

Balancing Reservoirs

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