Engineering Procedures Engineering Procedures for for
Micro Hydropower SystemsMicro Hydropower Systems
EBARA Hatakeyama Memorial FundTokyo, Japan
Micro Hydro Unit beside Irrigation WeirMicro Hydro Unit beside Irrigation Weir
AABB CC
EE
FF
GG
Irrigation Weir
A Intake
B Lateral By-pass Canal
C HeadTank
E GeneratingUnit
F Tailrace
G Transmission/Distribution Line
- whenever a weir imposes an excess head relatively to the downstream delivery flow, a micro unit can be envisaged in order to replace a dissipation structure.
- along an irrigation canal system, significant difference topographic level can be used and diversion scheme can be implemented out of irrigation period.
““Run of RiverRun of River”” type Micro Hydro Generation type Micro Hydro Generation SystemSystem
AABB
CC
DD
EE
GG
A Intake
B Lateral By-pass Canal
C Head Tank
D Penstock Pipe
E Generating Unit
G Transmission/Distribution Line
In order to take the advantage of a local significant difference topographic level created by a weir or a small dam, only a part of stream flow is used to generate power.
Micro Hydro Selection ChartMicro Hydro Selection Chart
Features :-Irrigation Pump as Turbine type generating unit
-Low head range from 2(m) to 12(m) is applicable for Micro Hydro Generating Unit.
To be givenQ, Hg, L
Predetermination of penstock dia., configuration of intake and trash rack
Calculation of Head Losses Hι
Calculation of Net Head He
Finding Unit Output from “SELECTION CHART” by using He and Q
Can Max. Unit Output get from Q, Hg, and L given ?
Sele
ctio
n of
ot
her
pens
tock
dia
met
er
No
Yes
Determination of Unit Number to be installed
Investigation of necessity for step-up transformer
Flow Chart of Micro Hydro Turbine Selection
Hydrograph :Hydrograph shows how flow varies through the year and how many months in a year that a certain flow is exceeded.
Flow Duration Curve (FDC):FDC can be produced by ordering the recorded water flows from maximum to minimum flow as shown in this figure.
An Example of Flow Duration Curve
Turbine Design Flow
Turbine Design Flow(Qt )
River Flow Duration Curve
Qt = Qr - QcQt : Turbine Design Flow
Qr : River Flow
Qc : Compensation Flow
Design Flow for Stand-alone System :
The design flow should be the flow that is available 95% of the time or more.
: Qr
Qt
Qc
An Example of Case Study
Gross Head Hg=4.3(m)
Hydrograph at the site :
Flow
(m3 /s
)
View from downstream side
Spill Way at Kampong Tuol
Since the rainfall volume is quite different at the rainy season and dry season, the micro hydro hybrid system with solar and/or biomass will be suitable for this area.
Photo at the end of dry season
There is no spill water from Spillway.
Photo at the end of rainy season
Proposed Location for Micro Hydro Unit
Pump Station
Irrigation Gates
View from downstream side of irrigation gates
Proposed location of Micro Hydro Unit
About 100 households are located around this bridge. Only few rich houses are connected to private power supplier, the unit cost of electricity is US$0.56/kWh .
Intake Screen
H.W.L.L.W.L.
Siphon Intake Facility
Existing Gates Facility
Bridge for National Road No.3
ReservoirT.W.L.
Penstock
Power House
Turbine Generator Unit
Existing Right Bank
Hg=4.3(m)
Downstream
Φ350 mm
Φ450 mm
Penstock Length :
Φ450mm = 3.5m, Φ350mm = 25m
Inlet ①
Elbow②
Elbow③Elbow④
Head Losses Calculation
One Unit Stand-alone System
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
0 50 100 150 200 250 300 350 400
Days
Riv
er
Flo
w (
m3/s)
Turbine Design Flow(=0.25m3/s)
River Compensation Flow(=0.2m3/s)
Flow Duration Curve
Turbine Design FlowHydrograph
0.25(m3/s)
Head Loss in the PenstockHL1 =HLp x L
where, HL1 : Head loss in the penstock(m)
HLp : Head loss per 1 m of penstock(m)
L : Total Length of Penstock(m)
HL
p
0.0072
0.025
D(m) L(m) HLp HL (m)
0.45 3.5 0.0072 0.025
0.35 25.0 0.025 0.625
ΣHL1 0.650
ζ=0.3
HL11 = ζV1
2
2g
V1 =Q
(π/4・D12)
= 0.25(0.785 x 0.452)
=1.57(m/s)
= 1.5720.3x 2 x 9.8 =0.038(m)
Q=0.25(m3/s)
Siphon Inlet Head Loss(HL11 )
D(m) V(m/s) Θ(deg) R/D ζ HL (m)
Bend② 0.45 1.57 135
2.5
0.169 0.022Bend③
0.35 2.6045 0.097 0.033
Bend④ 90 0.138 0.048ΣHL2-4 0.103
Bend Pipe Head Losses (HL2-4 )
V2HL = ζ 2g
Draft Tube Outlet Head Losses(HLd )
Type : 350SZT
D1 =350(mm)
D2 =550(mm)
HLd = 2gVd
2= 1.052
2 x 9.8 =0.056(m)
Vd = (π/4)xD22
Q =1.05(m/s)
Turbine Net Head (He)
He=Hg-HL =4.3-0.847=3.45(m)
Hg =4.3(m) : Gross Head
HL =HL11 + ΣHL1 + ΣHL2-4 + HLd
=0.038 + 0.650 + 0.103 + 0.056=0.847(m)
Say He=3.4(m)
Bore Diameter (mm)
200 250 300 350
Turbine Speed (rpm)
1000 750 600 500 1000 750 600 500 750 600 500 429 750 600 500 429
Generator Speed (rpm)
1,500 1,500 1,500 1,500
Generator Output (kW)
6 3 1.75 1 12 10 5 3 22 12 7 5 33 25 15 8
Head Losses Hι2
(m)0.23 0.17 0.10 0.07 0.30 0.22 0.17 0.12 0.31 0.24 0.15 0.11 0.35 0.31 0.24 0.17
Rough Net Head Calculation
(Note)The Head Losses(HL2 ) includes Siphon Intake and Draft Tube Outlet.
Table 1 Head Losses in Unit Conduit System
The Net Head(He) can calculate roughly by “Table 1” and Fig.4
He=Hg – (ΣHL2-4 + Hι2 )=4.3 -(0.650 + 0.17)=3.48(m)Table 2Fig.4 ≒3.45(m)
Micro Hydro Selection ChartMicro Hydro Selection Chart
He=3.4(m)
Qt=
0.25
(m3 /s
)
Select Turbine Type : 350SZ
Turbine Speed : 429(rpm)
0.00
1.00
2.00
3.00
4.00
5.00
6.00
7.00
8.00
0.10 0.15 0.20 0.25 0.30 0.35 0.40
Turbine Flow (m3/s)
Net
Head (
m)
50.0
55.0
60.0
65.0
70.0
75.0
80.0
85.0
0.10 0.15 0.20 0.25 0.30 0.35 0.40
Turbine Flow (m3/s)
Turb
ine E
ffic
iency (
%)
ηt=80.5(%)
Q=0.25(m3/s)
He=3.4(m)
Turbine Expected Output PT =9.8 x Q x He x ηt=9.8 x 3.4 x 0.25 x 0.805=6.7(kW)
Q – H Curve
Turbine Performance Curves
Q – ηt Curve
Bore Dia.=350(mm)
Turbine Speed=429(rpm)
50.0
55.0
60.0
65.0
70.0
75.0
80.0
85.0
0.10 0.15 0.20 0.25 0.30 0.35 0.40
Turbine Flow (m3/s)
Turb
ine E
ffic
iency (
%)
0.00
1.00
2.00
3.00
4.00
5.00
6.00
7.00
8.00
0.10 0.15 0.20 0.25 0.30 0.35 0.40
Turbine Flow (m3/s)
Net
Head (
m)
He=2.7(m)
He=5.0(m)
Recommended Operating Range
Recommended Operating Range
Recommended Turbine Operating RangeQ – H CurveQ – ηt Curve
Range of Turbine Output =4.8~11.0(kW)
Expected Annual Energy OutputExpected Generator Output Pg :
Pg=PT x ηb x ηg
=6.7 x 0.9 x 0.9=5.4(kW)
PT : Turbine Output (=6.7kW)
ηb : V belt pulley transmission efficiency (≒90%)
ηg : Generator Efficiency(≒90%)
Annual Energy Output E :
E=Pg x Day x 24
=5.4 x 295 x 24=38,232(kWh)
Pg : Generator Output(=5.4kW)
Day : Available running day number
Two Units System
0.15(m3/s)
0.15(m3/s)
Turbine Design Flow
Micro Hydro Selection ChartMicro Hydro Selection Chart
He=3.4(m)
Qt=
0.15
(m3 /s
)
Select Turbine Type : 300SZ x 500(rpm) or 250SZ x 600(rpm)
1. Select the bore diameter of Turbine from “Selection Chart” by approx. Net Head and Turbine Flow.
2. Obtain the operating point on each bore diameter’s performance curves(i.e., Q-H, Q-Eff. Curves) by changing turbine speed.
3. Re-calculate the Net Head for one unit and two units operation by using the turbine flow obtained from turbine performance curves.
4. Re-check the operating point of turbine.
5. Calculate “Annual Energy Output” based on Flow Duration Curve.
Turbine Selection Procedure
Similarity Law for PATSimilarity Law for PAT
Similarity Law can be applicable to PATs with similar flow shapes.
The performance of large scale PAT will be slightly improved by “Dimensional Effect”.
Turbine Head and Flow at Dif ferent Speeds
0.00
1.00
2.00
3.00
4.00
5.00
6.00
7.00
8.00
9.00
0.00 0.05 0.10 0.15 0.20 0.25
Tu rbin e Flow (m3 /s)
He
ad (
m)
5 0 0 (rpm)
600 (rpm)
750 (rpm)
1 ,000 (rpm)
▲ means the Best Effic ie ncy Po in t fo r each Tu rbine
Pump Bore Dia. : 2 50 (mm)
Impe lle r Type : Mixed Flow type
Turbine Head and Flow at Different Speeds
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
4.00
0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.10 0.11 0.12 0.13 0.14
Turbine Flow (m3/s)
Head
(m
)
50.0
55.0
60.0
65.0
70.0
75.0
80.0
85.0
90.0
0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.10 0.11 0.12 0.13 0.14
Turbine Flow (m3/s)
Eff
icie
ncy
(%)
500rpm
600rpm 750rpm
Site Curve
500rpm
600rpm
750rpm
Q-Eff. Curves
Q-H Curves
The speed of the turbine will vary according to the load, and there is a different head-flow curve for each speed.
Three such curves are shown in the left. The middle curve, labeled 600rpm is for the normal operating speed. The curves labeled 750rpm and 500rpm are for speed higher and lower than normal operating speed.
Note that for each speed, the operating point is given by the intersection of the turbine curve with the site curve.
Turbine Performance Curves at Speed Change
Site Curve : H=Hg – KQ2
0.0
5.0
10.0
15.0
20.0
25.0
30.0
35.0
0.00 0.05 0.10 0.15 0.20 0.25 0.30
Turbine Flow (m3/s)
Head
(m
)
0.0
10.0
20.0
30.0
40.0
50.0
60.0
0.00 0.05 0.10 0.15 0.20 0.25 0.30
Turbine Flow (m3/s)
Outp
ut
(kW
)
Output Control by Valve
Site Curve without valve control
Site Curve with valve control
Q-H Curve under constant speed
Turbine Output Curve
P1 =37kWP2 =32kW
bep
Site Curve :
Gross Head – Friction losses in the conduit
Operating point
0.0
1.0
2.0
3.0
4.0
5.0
6.0
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5
Flow (m3/s)
Head (
m)
50
55
60
65
70
75
80
85
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5
Flow (m3/s)
Eff
icie
ncy (
%)
300mm Bore Dia. Turbine
Gross Head Hg=4.3(m)
He=3.7(m)
He=2.95(m)
One Unit RunningTwo Units Running
Q-H C
urve
Q-H Curve
Site Curve
Turbine Speed : 550(rpm)
0.0
1.0
2.0
3.0
4.0
5.0
6.0
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4
Flow (m3/s)
Head
(m
)
50
55
60
65
70
75
80
85
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4
Flow (m3/s)
Eff
icie
ncy (
%)
250mm Bore Dia. Turbine
Gross Head Hg=4.3(m)
He=4.0(m)He=3.45(m)
Q-H C
urve
One Unit RunningTwo Units Running
Site Curve
Turbine Speed : 600(rpm)
Expected Annual Energy Output
300SZT 250SZT
He(m) Q(m3/s) ηt(%) Pt(kW) Pg(kW) He(m) Q(m3/s) ηt(%) Pt(kW) Pg(kW)
At One Unit
Running
3.70 0.180 81.0 5.29 4.28 4.00 0.133 77.5 4.04 3.27
At Two Units
Running
2.95 0.157 81.0 3.68 2.98 3.45 0.125 79.8 3.37 2.73
Annual Energy Output (kWh)
48,559 46,283
- Equivalent CO2 Gas Reduction : approx. 34~36(t-CO2 /year)(GHG emission rate : 0.740kg CO2 /kWh at the island of Java)
- Equivalent Capacity of Photovoltaic Generation : ≒58kWp(Average Solar Radiation : 4.86kWh/m2/day)
0.0
1.0
2.0
3.0
4.0
5.0
6.0
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5
Flow (m3/s)
Head (
m)
50
55
60
65
70
75
80
85
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5
Flow (m3/s)
Eff
icie
ncy (
%)
Site Curve “A”
Site Curve “B”
Penstock
Site Curve "A" 450mm Dia. X 3.5m, 350mm Dia
x 25m
Site Curve "B" 450mm Dia. X 3.5m, 400mm Dia
x 25m
Different Penstock DiameterTurbine Bore Dia. : 300(mm)
Turbine Speed : 550(rpm)
One Unit RunningTwo Units Running
Gross Head Hg=4.3(m)
Generator type Advantages Disadvantages
SynchronousGenerator
・ available of isolated operation・ adjustable of voltage,frequency
& power factor
・ need for complex controland insulated rotor winding
InductionGenerator
・ simple construction・ simple control system
・ to be get excitation from thegrid
・ parallel operation only
Items to be considered at Generator Selection :
★In case of isolated operation, Synchronous generator shall be applied.
★Rotor & bearing shall be designed to withstand the overspeed at load rejection
Estimated Overspeed : approx. 1.8 times of rated speed
Generator for Micro Hydro PlantGenerator for Micro Hydro Plant
Diesel Engine Generator can be applied by Siphon Intake System
Construction of Synchronous & Induction GeneratorConstruction of Synchronous & Induction Generator
Synchronous Generator
Induction Generator
Net Head vs Runaway Speed Curve
0
500
1,000
1,500
2,000
2,500
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Net Head (m)
Runaw
ay S
peed (
rpm
)Turbine Runaway Speed
If the turbine generator load is cut off under this running (on the other words, turbine generator load rejection), the unit speed will be increased to approx. 1,500(rpm) without the closing of turbine inlet valve. If this speed is continuing for a long hours, the turbine generator will be damaged by extreme high temperature of bearings and etc
Siphon Intake System
The generator for diesel engine, available to purchase in the market, can be connected to the turbine by applying Siphon Intake System.
M P P M
ELC
Dummy Load Pump
Booster PumpApprox. 3.0 ~3.2m
250φSZ type Micro Hydro Unit
Head Tank(approx.21m3)
Siphon Priming Tank(approx. 1m3)
Siphon Valve Operating Lever
Dummy Load Governor
Dummy Load Resistance
Loads
Domestic use Water
Over Flow PipeSump Pit
Skeleton of Test Stand for SZ type Micro Hydro Generating Unit without Vacuum Pump
①
②
③
④
⑤
⑥
⑦
Opened Position
Closed Position
WL
① Siphon Pipe
② Valve Disc
③ Operating Rod
④ Valve Yoke
⑤ Valve Operating Lever
⑥ Valve Locking Rod
⑦ Vortex Prevent Plate
Starting Procedure of Micro Generating Unit :1. Keep the Siphon Valve Disc in “Closed Position”
by Valve Operating Lever & Locking Rod.
2. Prime the Siphon Pipe with the water of “Siphon Prime Tank” .
3. Open the Turbine Inlet Valve and Siphon Valve simultaneously, then the Unit will be started.
4. Lock the Valve Operating Lever in “Open Position” by Valve Locking Rod”.
Siphon ValveView View ““AA””
““AA””
Turbine Construction
Bore Dia. : 200~250mm Bore Dia. : 300~350mm
Turbine CasingTurbine CasingTurbine RunnerTurbine Runner
Single Line Diagram for Generator Control Panel
#51 : Over Current Protection Relay
#52 : Circuit Breaker
#59 : Over Voltage Protection Relay
ELC : Electronic Load Controller
Generator Control PanelGenerator Control Panel (Dummy Load Governor)(Dummy Load Governor)
- It is necessary for the output of a micro-hydro power plant, which has no back-up power generation source, to always exceed the demand.
- A dummy load governor is usually installed to control the load (demand) fluctuation, on other words, to control the balancing of both actual load and dummy load by thyristor (i.e., to keep the summation of both actual and dummy load in constant for the same output of generator.)
Dummy Load Governor
Thyristor
Principle of Light Dimmer by Thyristor
Before adjusting Little adjusted adjusted
Bright Little Bright dark
Thyristor
OFF ON
Thyristor
Thyristor Control Lamp Brightness
Light Dimmer by Thyristor
Type of Governor Theory of Governor Control Features
Phase Angle Control
・The same principle with Triac used in Light Brightness adjusting・Not available for Induction Generator System・Waveform distortion which produces increased heating in the generator windings. To compensate for the waveform distortion, the generator should be oversized.
Binary Weighted Loads
・Prototype of Dummy Load Governor・Waveform distortion is not produced and the ballast load is resistive.・Complexity resulting from requiring a number of ballast loads, each with its connections, wires and switching device.・Because the ballast load is only varied by fixed steps, the voltage is only controlled within a range. →Poor voltage control
Mark-space Ratio Controller
The mark-space ratio controller, in its simplest form, requires just a single ballast load. The ballast load is connected across the rectified output of the generator and switched on and off by means of a transistor.・Good voltage regulation, simple connection of ballast loads and an effectively resistive ballast load.・There is no phase balancing and there is increased waveform distortion.
Features of each Dummy Load type Governor
Effective use in the daytime electricity
To avoid the consuming of excess electricity by dummy load due to small demand in the day time, it is preferable to plan the use of excess power for local industries such as rice mill, coffee mill and etc. in the day time.
Transmission and Distribution Lines
If the voltage drop at the terminal of distribution line and/or transmission line is over 5% of rated generator voltage, the using of large size power cable and/or voltage step-up transformer is preferable.
Voltage Drop in Transmission Line
Existing Micro Hydro Unit Existing Micro Hydro Unit in Indonesiain Indonesia
Head TankHead Tank
Intake Screen(20mm Space x 5mm t)
Spillway Water Conduit from Intake Weir(450~500mmdia)
Overflow WL
Intake Screen
Penstock
Outline Dimensions of Head Tank
“A”
View “A”
PenstockPenstock
Head tankHead tankFunctions of Head tank:
- Controls the variation of flow from the headrace and into the penstock cause by load fluctuation.
- Finally remove the debris (sediments, leaves, driftwood, etc.) in flowing water.
(Source) Manual for Micro-Hydropower Development(JICA))
TurbineTurbine : Model 200SZ (EBARA)
Serial No. P0690-03
Date B-01
Bearing 93008ZZ 9309ZZ
GeneratorGenerator : Maker : Huafa
AC Synchronous Generator
5kW Cosφ 1.0 230V 21.8A 50Hz
1,500rpm 1 Phase
Excit Volt 49V Exciter Circuit 2.6A
Insulation Class B RAT S1
100kW Micro Hydropower Plant (installed for a tea estate in West Bengal, India)
** The cost of micro hydro schemes installed by PLN range from $1,000/kW to $2,900/kW. Low project development costs for micro hydro systems have mostly been obtained by utilizing electro-mechanical equipment of local manufacturers.
**For mini hydro development the range is roughly between US$1,500 and US$2,500 depending on local conditions. Economic analyses show that the schemes installed by PLN are substantially less expensive than the conventional diesel option as the electricity cost range from 2.5 to 6.9 cents USD/kWh.
Mini/Micro Hydro Development CostMini/Micro Hydro Development Cost
Feasibility Studies for Micro Hydropower Generation
Part 1:1. “Walk the site” to understand the existing site layout2. Take accurate measurement of all relevant levels across site3. Identify the load connected to the Micro Hydropower
Generation4. Discussion with client on site potential
Part 2:1. Use long-term flow data(if available) to produce an estimated
flow duration curve for the site.2. Specify most appropriate turbine type and size.3. Discuss most suitable location for the hydro systems.4. Outline civil engineering works required.5. Specify distribution and generator type6. Calculate expected power output, annual energy production
and value of electricity produced.7. Estimate total project cost.
End
For further Questions, please contact to
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Micro Hydro Turbine Driven PumpMicro Hydro Turbine Driven Pump