micro hydro engineering procedure(ptei '08)f

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)


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


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


He=3.7(m)

He=2.95(m)

One Unit RunningTwo Units Running

Q-H C

urve

Q-H Curve

Site Curve


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


He=4.0(m)He=3.45(m)

Q-H C

urve


Site Curve


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)




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

[email protected]

or

[email protected]

Micro Hydro Turbine Driven PumpMicro Hydro Turbine Driven Pump

micro hydro engineering procedure(ptei '08)f

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