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Introduction to Hydro Power 15 April 2009 Monterey Institute for International Studies. Chris Greacen [email protected]. Outline. Solar, wind, hydro – brief comparison Hydro system overview Some examples from Thailand and elsewhere Site assessment Head Flow Penstock length - PowerPoint PPT Presentation
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Introduction toHydro Power
15 April 2009Monterey Institute for International Studies
Introduction toHydro Power
15 April 2009Monterey Institute for International Studies
Chris [email protected]
Outline• Solar, wind, hydro – brief comparison• Hydro system overview• Some examples from Thailand and elsewhere• Site assessment
– Head– Flow– Penstock length– Transmission line length
• Civil works• Mechanical• Electrical
Sun, Wind, & Water
Micro-hydropower overview
Source: Inversin, A. R. (1986). Micro-Hydropower Sourcebook.
Mae Kam Pong, Chiang MaiDEDE + community40 kW$130,000 costSell electricity to PEA – $13,000 per year
Thai Potential:1000s of projects - 700 MW (?)
Huai Krating, TakPower: 3 kWHead: 35 meterFlow: 20 liters/secondCost: <$6,000
(turbine - $700 baht)
Kre Khi village, Tak Province1 kW for school, clinic, churchCost: <$3,500
(turbine $250)Head: 10 metersFlow: 15 lit/sec
Mae Klang Luang, Chaing Mai200 watts$120 (turbine: $90)Installed: 2007Head: 1.7 meters
Micro-hydroelectricity: Estimating the energy available
Image Source: Inversin, A. R. (1986). Micro-Hydropower Sourcebook.
heightPower = 5 x height x flow
Watts meters liters per second
Measuring height drop (head)
• Site level• Pressure gauge
Sigh
t lev
el m
etho
d
Hose & Pressure Gauge• Accurate and simple method.• Bubbles in hose cause errors.• Gauge must have suitable scale and be calibrated.• Use hose a measuring tape for penstock length.• Feet head = PSI x 2.31
H1
Measuring Flow
• Bucket Method• Float Methoddesign flow = 50% of dry-season flow
Bucket Method
Float Method
Flow = area x average stream velocity
Image source: Inversin, A. R. (1986). Micro-Hydropower Sourcebook.
Civil Works – some golden rules
• Think floods, landslides
• Think dry-season.• Try to remove
sediment• Maximize head,
minimize penstock– “wire is cheaper than
pipe”
Source: Inversin, A. R. (1986). Micro-Hydropower Sourcebook.
Weir
A Sluice allows sediment removal.
Locating the Weir & Intake
Weir
Intake
Head Race
Trash RackSilt Basin
Penstock
Intake directly to penstock
• If spring run-off sediment is not severe, the penstock may lead directly from the weir.
Weir
Penstock
Screened Intake
Side intake
Trash rack: keeps the big stuff out
Screens
• Screen mesh-size should be half the nozzle diameter.• A self-cleaning screen design is best.• The screen area must be relatively large.
Screen
PenstockHead Race
Silt Basin
Source: Inversin, A. R. (1986). Micro-Hydropower Sourcebook.
Power Canal (Head Race)
• It may be less expensive to run low pressure pipe or a channel to a short penstock.
4” Penstock
6” Penstock
Head Race
Forebay (Silt basin)• Located before penstock• Large cross-sectional area, volume Water velocity reduced
sediment (heavier than water but easily entrained in flow) has opportunity to drop out.
Source: Inversin, A. R. (1986). Micro-Hydropower Sourcebook.
Penstocks• A vent prevents vacuum collapse of the penstock.• Valves that close slowly prevent water hammer.• Anchor block – prevents penstock from moving
Penstock
Valve
Vent
Pressure GaugeValve
Anchor Block
Penstock diameter
Hazen-Williams friction loss equation:
headloss friction (meters) =(10.674*(F/1000)^1.85)/(CoefFlow^1.85*D^4.87)*L
Where:F = flow (liters/sec)CoefFlow = 150 for PVCD = penstock diameter (mm)
Penstock materials
• Poly vinyl chloride (PVC)• Polyethylene (PE)• Aluminium• Steel
Anchor and Thrust Blocks
Source: Inversin, A. R. (1986). Micro-Hydropower Sourcebook.
Locating the Powerhouse• Power house must be above flood height.• Locate powerhouse on inside of stream bends.• Use natural features for protection.
Micro-hydro technology
Pelton Turgo Crossflow Kaplan Centrifugal pump
Turbine application
http://www.tycoflowcontrol.com.au/pumping/welcome_to_pumping_and_irrigation/home4/hydro_turbines/turbine_selection (April 18, 2003)
Efficiency and Flow
0.2 0.80.60.4 1.0Fraction of Maximum Flow
Eff
icie
ncy
50%
00%
100%Pelton and Turgo
Crossflow
Francis
Propeller
Generators
• Permanent magnet• Wound rotor synchronous• Induction (Asynchronous)
Permanent Magnet Generator
• Rotor has permanent magnets• Advantages
– No brushes– Efficient
• Disadvantages– Generally limited in size to several kW– field not adjustable (except ESD)
• Some do AC• Some do AC and rectify to DC• Some do both
Adjustable permanent magnet generator
DC Alternator (automotive)• Produces rectified
alternating current.• Readily available.• Easy to service.• Brushes need replacing.• A rheostat controls
excitation.
DC Alternator (automotive)
• May be rewound for lower rpm at low head.• The field may need a battery boost to start.• Use high voltage ac output with a step-down
transformer and rectifier for long transmission distance.
• Used in many all stand-alone applications.• Single phase up to 10 kW.• 3-phase up to >100,000 kW • Advantage:
– Industrial standard– Frequency and voltage regulation
• Disadvantage– Wound rotor – not tolerant to overspeed– Harder to connect to grid
(wound rotor) Synchronous Generator
(wound rotor) Synchronous Generator• Most large machines use field coils to
generate the magnetic field.• Rotating magnetic field induces alternating
current in stator windings.
AVR
Rotor Field WindingExciter Winding
Exciter Field WindingStator Output WindingRectifier
(wound rotor) synchronous generator
Big50,000,000 watts
small2,000 watts
Asynchronous (Induction) Generator
• Just an induction motor with negative slip.• Used with:
– grid-tie system (up to 1 MW)– Off-grid stand-alone (often in ‘C-2C’ configuration)– Can be used with battery based systems
Induction motor/generator
Induction Generator
• Advantages– Simple and robust.– Tolerant to overspeed– Readily available– inexpensive
• Disadvantages– Frequency regulation ‘loose’ in stand-alone applications– Requires external excitation
• When used in off-grid,an ‘ELC’ controls voltage
Single-phase 230 volt power to the resort grid
Fused cutout, 230 volt
Volt-meter (0-500 volt)
flow switch (open-circuit when no-flow) HFS-25
LN
X
Indicator lamp
V
Single-phase 230 vac 50 Hz kWh meter
AC Ammeter (0 to 5 Amp)
A
Wires from electrical panel to pump 5.5 meters
Outflow pipe
Induction generator (mini) grid-tie example
Wires from electrical panel to flow switch 5.5 meters
Induction grid-tie example1 MW Mae Ya
15A 10A
ToVillage
TotalCurrent235V
3000W
ELC
BallastCurrent
3kW Ballast Load
380V
Motor Run Capacitors
in Box
6A
4 kVA 380V
C25μF
2C50μF
Huai Krating:‘pump as turbine’ off-grid induction “C-2C”
Capacitors for external excitation of induction motors: theoretical overview of LC oscillators
Calculating “C” in C-2C
• Apparent power (VA): S = √3(IV)• Real Power (W): P = S cos(φ)• Reactive power (VAR): Q = √(S2 - P2)• Reactive power per phase: q = Q/3• Capacitor current: Ic = q/V• Capacitance (micro-F) for delta: C = 106 x Ic / (2πfV)
• … but don’t worry… it’s all in the spreadsheet.
• Use “motor run” not“motor start” capacitors
Mae Wei:‘pump as
turbine’ off-grid induction
power lines: single phase 230 vac to village. 2 @ 25 mm Al
Capacitor 70 microfarad
Volt-meter (0-500 volt)V
A Ammeter 15 amp
A
V
Knife switch
Volt-meter (0-500 volt)
Ammeter 15 amp
Leonics controller Ballast load
A Ammeter 15 amp
Three phase 230 vac delta
Powerhouse
SchoolTo village loads…
Capacitor 140 microfarad
Mae Wei – ‘pump as turbine’ off-grid induction
RegulationWith batteries
AC direct
Permanent magnet Trace C-40 type, etc.
Wire to output of Outback
ELC (voltage)
Synchronous Trace C-40 type Governor (frequency)
AVR (voltage)
Induction Trace C-40 type
Wire to output of Outback
ELC (voltage)
Capacitors for frequency
Regulation – synchronous generators… typically both voltage
and frequency
• Voltage decreases as load current increases.• The Automatic Voltage (AVR) regulator
increases the field excitation to compensate.• Prolonged underspeed can damage an AVR.• Still required with a load controller because
load power factor can change.
Mechanical Governing
• As load varies, mechanical control keeps frequency constant by varying water flow– Advantage:
• Saves water
– Disadvantage:• Electro-mechanical moving parts• Slower reacting• More expensive
Deflector
Electronic Governing
• Types1. Phase angle2. Binary controller3. Pulse Width Modulation
• Dump load: – water heating– air heating– lightbulbs (not recommended)
Mae Wei – ‘pump as turbine’ off-grid induction
Applying Common Property Theory to Village Power Systems
Definition of a common pool resource (Oakerson 1992; Ostrom 1994):
• System has limited yields• difficult to exclude individual users from using
too much
0
5
10
15
20
25
30
8/6/
01 0
:05
8/6/
01 6
:05
8/6/
01 1
2:0
5
8/6/
01 1
8:0
5
8/7/
01 0
:05
8/7/
01 6
:05
8/7/
01 1
2:0
5
8/7/
01 1
8:0
5
8/8/
01 0
:05
8/8/
01 6
:05
8/8/
01 1
2:0
5
8/8/
01 1
8:0
5
Am
ps
0
50
100
150
200
250
300
Vo
lts
Current 1 Current 2 Current 3 Voltage
Mae Kam Pong Microhydro Unit #2 Voltage andCurrent (15 minute intervals) 6 Sept to 8 Sept 2001
Low evening time voltage:symptom of a common property problem
• Rules governing user behavior should match with the technical characteristics of the system
• kWh Meters are a mismatch for microhdyro
• Should be concerned with kW, not kWh
• Low voltages… kWh meter is a culprit
5am
7am
9am
11am
1pm
3pm
5pm
7pm
9pm
11pm
S1
0
100
200
300
400
500
600
wat
ts
Circuit breakers: a technical fix for a common property problem
XkWh meter
OKMini-circuitbreakerMini-circuit breaker can encourage peak load reduction
5:00
6:00
7:00
8:00
9:00
10:0
0
11:0
0
12:0
0
13:0
0
14:0
0
15:0
0
16:0
0
17:0
0
18:0
0
19:0
0
20:0
0
21:0
0
22:0
0
23:0
0
1985
1988
1991
1994
1997
2000
0
1000
2000
3000
4000
5000
6000
7000
Watts
Time of day
Year
Hourly load curve, by year from 1985 to 2000. Graph based on an appliance usage survey of 35 families in Mae Kam Pong village, April
and June 2001.
Contribution to evening maximum peak demand by appliance, for the years 1985 – 2001.
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
10000
1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001
Wa
tts
other
water boiler
rice cooker
iron
fridge
TV
lights
Thank you
… and please bring tools for Saturday hands-on PV workshopwrenches
pliersscrew driversleatherman
For more information, please contact [email protected]
This presentation available at:www.palangthai.org/docs