micro hydro testing

8/8/2019 Micro Hydro Testing

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Fundamental Characteristics of Test Facility for Micro

Hydroelectric Power Generation System

T. Sakurai1, H.Funato

2and S.Ogasawara

3

1 Tomoyuki Sakurai and 2 Hirohito Funato/Utsunomiya University Department of Electrical and Electronic Engineering 7-1-2 Yoto,Utsunomiya, Tochigi, Japan 321-8585

3Ogasawara Satoshi/Hokkaido University Department of System Science and Informatics zyonishi 9-chome kita-ku kita14,

Sapporo, Hokkaido, Japan 060-0814

Abstract-This paper proposes a test facility for micro hydraulic

generation system. Micro hydraulic generation system is very

difficult to exam their characteristics including hydraulic turbine

because water flow in various conditions is necessary but it is very

difficult to realize in laboratory. In this paper water flow is

realized using general purpose pump that can add pressure to

water flow to simulate water drop. From obtained experimentalresults, a simulation model of hydro turbine was built in order to

establish high efficiency control system.

Index Terms - Micro hydroelectric power generation, IPM

synchronous generator, turbine model, MPPT.

I. I NTRODUCTION

Recently global warming becomes big problem. Therefore the

development of the clean energy that does not discharge CO2 is

strongly expected. Micro hydroelectric power generation is one

of the attract choices(1) ~ (4)

. Micro hydraulic power generation is

with small, simple facilities and has stable output. The authors

have studied a new micro hydraulic power generation with

simple mechanism and high efficiency. The proposed system

was tested in a real river (5)(6)

. Micro hydraulic generation system

is very difficult to exam their characteristics including hydraulic

turbine because water flow in various conditions is necessary

but it is very difficult to realize in laboratory. This paper

proposes a new test facility for micro hydraulic generation

system. In this system, a water flow is realized using general

purpose pump that can add pressure to water flow to simulate

water drop. Fundamental characteristics are obtained using the

proposed facility toward high efficiency micro hydraulic

generation system.

II. SYSTEM CONFIGURATION

Outline of the proposed test facility for micro hydroelectric

power generation system is shown in Fig.1. The top right corner

of Fig.1 shows the inside of the generation system box

connected to a hydraulic turbine. Configuration of the test

facility is show in Fig.2. The water tank can save water then the

saved water is drawn in general purpose submersible pump and

supplied to a hydraulic turbine through the hose. Pressure gauge

and flow meter are installed in the upper part at the hose.

Therefore its pressure head and velocity head can be calculated

using measured pressure and flow. A general-purpose

centrifugal pump is used as reversible pump-turbine. The

centrifugal pump is one of the most popular pumps which can

generate pressure by centrifugal force caused by the turn of the

impeller. The exit of the reversible pump-turbine is connected

with the hose to a water tank. The provided machine energy by ahydraulic turbine is sent to an IPM synchronous generator

through the shaft then electric power is generated. A torque

meter is installed between a hydraulic turbine and IPM

synchronous generator so that efficiency of hydraulic turbine

and IPM synchronous generator can be measured separately.

Ratings of the centrifugal pump used as a hydraulic turbine and

the rating of IPM synchronous generator as motor operation is

shown in table 1.

The electric connection of micro hydroelectric power

generation system is shown in Fig.3. A general-purpose inverter

drives submersible pump and a diode rectifier is connected to dc

bus to establish the bus voltage. A PWM rectifier is connected to

IPM synchronous generator. Because it is difficulty to make a

big effective head physically in experiments, the water pump

with variable pump speed with inverter can raise pressure and

give effective head equivalently. A PWM rectifier is used to

realize variable-speed operation of the IPM synchronous

generator and load is connected to the dc bus. Because the

generated power is not controlled in the experimental system, a

diode rectifier is connected in parallel to resistive load. The

diode rectifier supplies the difference between load power and

generated power. Therefore in case of no generation power, the

load power is supplied entirely by the diode rectifier. Then the

increase of generated power cause decrease of supply power

from diode rectifier. The generated power is measured by thedigital power meter inserted between the IPM synchronous

generator and PWM rectifier. The controller is composed of

FPGA (Field Programmable Gate Array) combined with CPU

core so that position–sensor less control and maximum power

tracking control can be implemented in the near future(6) (7)

.

III. EXPERIMENT RESULT

As shown in Fig.2, effective head is equivalently realized by

pressurized water flow made by submersible pump with



Fig.1. Outline of the micro hydroelectric power generation system.

Fig.2. Configuration of the test facility micro hydroelectric power generation

system.

TABLE I

RATIONS OF HYDRAULIC TURBINE AND GENERATOR

Fig.3. Electric connection.

adjustable speed. Frequency of submersible pump can be

regulated from 0 to 50Hz. The height from the hose of the upper

part duct to a hydraulic turbine is 1.41m as shown in Fig.2. This

becomes potential head h. Pressure head h p and velocity head hv

can calculate from pressure P and flow Q measured with a

pressure gauge and the flow meter in the hose. h la is the loss of

head of the hose from a submersible pump to a pressure gauge. It

can be calculate from shape of the hose and the water flow of the

hose. Total head H of the whole system is

H = h + h p+ hv + hla. (1)

The head at the hydraulic turbine input becomes

H t = h + h p + hv − hlb. (2)

hl b is the head of loss of the hose from a pressure gauge to ahydraulic turbine. The water flowing into the hydraulic turbine

turns the runner anticlockwise direction seeing from the

generator side and generates electricity. Because IPM

synchronous generator is operated by simple V/f control, speed

of IPM synchronous generator and hydraulic turbine is decided

by PWM rectifier frequency. Because IPM synchronous

generator has 6 poles and the frequency of the PWM rectifier

can be regulated input from 0 to 50Hz, this means revolving

speed can be controlled from 0 to 1,000 rpm.

The relationship between water flow Q and revolving speed of

submersible pump under fixed generator frequency f g is shown

in Fig.4. Fig.4 (a) shows pressure P and (b) shows total head H .

Total head H is calculated from Eq. (1). From Fig.4, it is clear

that increase of revolving speed of submersible pump causes

increase of water flow and pressure. This results in increase of

total head. In Fig.(4) (a), when water flow Q is 200l/min, the

higher the generator frequency become, the bigger the resistance

of hydraulic turbine becomes. On the other hand, when water

flow Q is almost 500l/min, the resistance of the hydraulic

turbine at f g of 10Hz is higher than that at f g of 40Hz. In Fig.(4)

(b), the shape of curve is quite similar to that in Fig.4 (a) so that

it is clear that total head depends on pressure head.

The ratio of each head for total head at f g of 20Hz are shown in

Fig.5. The increase of revolving speed causes the increase of

total head. As mentioned previously, the increase of total head iscaused by increase of pressure. From Fig.5, it is clear that the

higher the total head becomes, the smaller the ratio of potential

head becomes and the bigger the ratio of pressure head becomes

because potential head is constant. The ratio of velocity head is

very small (less than 2%) so that the velocity head will be

ignored in the following of this paper.

Characteristics of hydraulic turbine in case of fixed generator

frequency f g ( f g =10, 20, 30, 40, 50Hz) are shown in Fig.6. The

horizontal axis is the head H t . The left vertical axis is power and

the right vertical axis is efficiency. The hydraulic turbine input

power P i, hydraulic turbine output power P t and hydraulic

turbine efficiency η t = P t P i are plotted in each graph. Hydraulicturbine input power P i is calculated by P i= 9.8QH t . In the

following, “head” means hydraulic turbine input head H t .

Hydraulic turbine output power P t is calculated by the product of

revolving speed and toque measured by toque meter. From

experimental results, it is clear that input and output power of

hydraulic turbine increase linearly. The characteristics of

hydraulic turbine efficiency change depending on frequency as

shown in Fig.6. From Fig.6(a), (b) and (c) maximum efficiency

point can be observed at 2.3m of the head at 10Hz of f g , 2.2m of

the head at 20Hz of f g and 4.1m of the head at 30Hz of f g

discharge 0.5 m3/min rated power as motor operation 1.5 kW

total head 12.7 m frequency 72.5 Hz

water power 1.85 kW poles 6

pump eff. 55 %

IPM synchronous generator hydraulic turbine

pressure gauge

submersible

pump

flow meter

torque

meter

hydraulic

turbine

water hose

water tank

hydraulic

turbine

IPM

synchronous

generator

pressure gauge flow meter

water tank

submersible pump IPM synchronous generator

torque meter

hydraulic turbine

water hose: water flow

shaft 1.2 m

pressure gauge flow meter

water tank

submersible pump IPM synchronous generator

torque meter

hydraulic turbine

water hose: water flow: water flow

shaft 1.2 m

IPMSG

power

meter

Inv.

PWM

Rec.Load

submersible pump hydraulic turbine

IPMSG

power

meter

Inv.

PWM

Rec.Load

submersible pump hydraulic turbine



0.00

2.00

4.00

6.00

8.00

10.00

12.00

0 100 200 300 400 500 600

flow Q [l/min]

t o t a l h e a d H [ m ]

fg=50Hz

fg=40Hz

fg=30Hz

fg=20Hz

fg=10Hz

0%

20%

40%

60%

80%

100%

1.24 2.09 3.26 4.64 6.11 7.80 9.38total head H [m]

loss of head [m]

velocity

head [m] pressure

head [m]

potential

head [m]

(a) pressure VS. flow

(b) total head VS. flow

Fig.4. Flow characteristic (constant generator frequency)

Fig.5. Ratio of each head (generator frequency f g = 20 Hz)

respectively. In case of Fig.6(d) and (e), maximum efficiency

point can not be observed because there may be at the higher head. From Fig.6(d), the output power of 402W is obtained at

the head of 9.25m.

Characteristics of generator in case of fixed generator

frequency f g ( f g =10, 20, 30, 40, 50Hz) are shown in Fig.7. The

horizontal axis is the head H t . The left vertical axis is power and

efficiency. The generator input power (= hydraulic turbine

output power P t ), the output power P g and efficiency η g = P g /P t

are plotted in each graph. The generator power is measured by

digital power meter. In the case when the generator power is

negative in Fig.7(a), the generator loss is not covered by

hydraulic turbine input power so that part of loss power is

supplied from PWM rectifier. The generator efficiency is

calculated only when the generator output power becomes

positive. From Fig.7, generator input power and output power

increase approximately linearly. In case of Fig.7(a), the

generator output power becomes negative to all head region so

that it is impossible to get electric power. From Figs.7(b), (c),

(d) and (e), generator efficiency increases according to theincrease of the head. From Fig.7(d), the maximum generator

efficiency of 76% and more then 300W generator output power

are obtained. In these experiments, the generator efficiency is

lower than its maximum efficiency because the voltage

coefficient of V/f control was not optimized. Therefore the

generator efficiency may be improved if optimized coefficient is

employed.

Each power and efficiency of hydraulic turbine and generator

for fixed generator frequency f g are shown in Fig.8. These

curves are calculated from Fig.6 and 7. The horizontal axes are

the head H t . Fig.8(a) shows the hydraulic turbine output power

P t , (b) shows the generator output power P g , (c) shows the

hydraulic turbine efficiency η t and (d) shows the generator efficiency η g . From Fig.8(a), it clear that the slope of the

hydraulic turbine output power depends on generator frequency.

This result in the optimum operation frequency should be

selected to get the maximum output power from hydraulic

turbine at a certain head. In Fig.8(b) the similar result was

obtained because generator output power depends on turbine

output power. From Fig.8(c), it is observed that each operation

speed has optimum head to get maximum efficiency of

hydraulic turbine. In Fig.8(d), the higher the head becomes, the

more the efficiency improved.

Each power and efficiency of hydraulic turbine and generator

for fixed head are shown in Fig.9. The horizontal axis is thegenerator frequency f g . Fig.9(a) shows hydraulic turbine output

power P t , (b) shows generator output power P g , (c) shows

hydraulic turbine efficiency η t and (d) shows generator

efficiency η g respectively. Because it is difficult to make

experiments at fixed head, Fig.9 is obtained from Fig.8 to

observe power and efficiency at certain head. From Fig.9(a),

when the head is over 3m, there is the optimum frequency to get

maximum turbine output power. The higher the head becomes,

the higher the optimum frequency is. Similar result can be

observed for IPM generator output power from Fig.9(b). From

Fig.9(c), the optimum generator frequencies f g to get maximum

hydraulic turbine efficiency become 24Hz, 30Hz, 37 Hz and

42Hz for the heads of 3m, 5m, 7m and 9m respectively. From

Fig.9(d), the optimum generator frequencies f g to get maximum

generator become 30Hz and 40Hz for the heads of 5m and 7m

respectively.

IV. SIMUＬATION MODEL OF HYDRO TURBINE FOR MXIMUM

EFFICIENCY

From obtained result, a simulation model of hydro turbine can

be built in order to establish maximum efficiency control. Using

established simulations, the control algorithm can be considered

0

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08

0.09

0 100 200 300 400 500 600

flow Q [l/min]

p r e s s u r e P [ M P a

fg=50Hz

fg=40Hz

fg=30Hz

fg=20Hz

fg=10Hz



-100

0

10 0

20 0

30 0

40 0

50 0

60 0

70 0

80 0

90 0

0.00 2.00 4.0 0 6.00 8.0 0 10.00

turbine input head H t [m ]

t u r b i n e i n p u t - o u t p u t p o w e r [ W ]

0

0. 1

0. 2

0. 3

0. 4

0. 5

0. 6

t u r b i n e e f f i c i e n c y

P i

P t

η t

turbine input power Pturbine output power Pturbine efficiency

turbine input power P i

turbine output power P t

turbine efficiency η t

turbine input power Pturbine output power Pturbine efficiency

turbine input power P i

turbine output power P t

turbine efficiency η t



-100

0

10 0

20 0

30 0

40 0

50 0

60 0

70 0

80 0

90 0

0.00 2.00 4 .00 6.00 8.0 0 10 .00



0

0. 1

0. 2

0. 3

0. 4

0. 5

0. 6


P i

P t

η t



-100

0

10 0

20 0

30 0

40 0

50 0

60 0

70 0

80 0

90 0

0 .00 2.00 4.0 0 6.00 8.00 10.00



0

0 .1

0 .2

0 .3

0 .4

0 .5

0 .6


P i

P t

η t



-100

0

10 0

20 0

30 0

40 0

50 0

60 070 0

80 0

90 0

0.00 2.00 4.0 0 6.00 8.0 0 10 .00



0

0. 1

0. 2

0. 3

0. 4

0. 5

0. 6


P i

P t

η t



-100

0

10 0

20 0

30 0

40 050 0

60 0

70 0

80 0

90 0

0.00 2.00 4 .00 6.00 8 .00 10 .00


t u r b i n e i n p u t - o u t p u

t p o w e r [ W ]

0

0. 1

0. 2

0. 3

0. 4

0. 5

0. 6

t u r b i n e e f f i c

i e n c y

P i

P t

η t



-200

-100

0

10 0

20 0

30 0

40 0

50 0

0.00 2 .00 4.0 0 6 .00 8 .00 10 .00


g e n e r a t o r i n p u t - o u t p u t p o w e r [ W ]

P g

P t

generator input power P t

generator output power P g

generator eff iciency η g

generator input power P t

generator output power P g

generator eff iciency η g


-200

-100

0

10 0

20 0

30 0

40 0

50 0

0.0 0 2 .00 4.00 6.00 8 .00 1 0 .00


g e n e r a t o r i n p u t - o u t p u t p o w e

[ W ]

0

0. 1

0. 2

0. 3

0. 4

0. 5

0. 6

0. 7

0. 8

g e n e r a t o r e f f i c i e n c

η gP g

P t


g e n e r a t o r e f f i c i e n c y

-200

-100

0

10 0

20 0

30 0

40 0

50 0

0.0 0 2 .00 4.00 6.00 8.0 0 1 0.0 0


g e n e r a t o r i n p u t - o u t p u t p o w e r

[ W ]

0

0. 1

0. 2

0. 3

0. 4

0. 5

0. 6

0. 7

0. 8

g e n e r a t o r e f f i c i e n cg

P g

P t



-200

-100

0

10 0

20 0

30 0

40 0

50 0

0.00 2 .00 4.00 6.00 8.0 0 1 0.0 0


g e n e r a t o r i n p u t - o u t p u t p o w e

[ W ]

0

0. 1

0. 2

0. 3

0. 4

0. 5

0. 6

0. 7

0. 8

g e n e r a t o r e f f i c i e n c yη g

P g

P t



-200

-100

0

100

200

300

400

500

0.00 2.00 4.00 6.00 8.00 10.00

turbine input head Ht [m]

g e n e r a t o r i n p u t -

o u t p u t

p o w e r [ W

]

0

0.1

0.2

0.3

0.40.5

0.6

0.7

0.8

g e n e r a t o r e f f i c i e n c yg

P g

P t



(a) generator frequency f g = 10 Hz

(b) generator frequency f g = 20 Hz

(c) generator frequency f g = 30 Hz

(d) generator frequency f g = 40 Hz

(e) generator frequency f g = 50 Hz Fig.6. Characteristic of hydraulic turbine.

(a) generator frequency f g = 10 Hz

(b) generator frequency f g = 20 Hz

(c) generator frequency f g = 30 Hz

(d) generator frequency f g = 40 Hz

(e) generator frequency f g = 50 Hz Fig.7. Characteristic of generator.



and testes, then the result can be feedback to experiments to

verify the obtained algorithm. One example of simulation of

PSIM is shown in Fig.10 which is same configuration to

experimental system. The hydro turbine model is composed of a

look-up table which has two inputs (water flow and speed of

generator) and one output (torque) and external control load

with inertia. Using this simulation model, the maximum

efficiency control will be considered.

V. CONCLUSIONS

This paper proposes a new test facility for micro hydraulic

generation system and to get fundamental characteristics. In the

examinations, characteristics of the hydraulic turbine and

generator are measured by several effective head equivalentlyrealized by submersible pump to adjust revolving speed. Output

power of 402W and maximum efficiency of 51% are obtained

for hydraulic turbine. Output power of over 300W and

maximum efficiency of 76% are obtained for generator. From

obtained experimental results, a simulation model of hydro

turbine was built. Using this simulation model, the maximum

efficiency control will be considered. This work was partially

supported by Grant-in-Aid for Scientific Research (c)

(KAKENHI) provided by Japan Society for the Promotion of

Science.

R EFERENCES

[1] T. Kikuchi R. Ozawa, J. Itsumi, and H. Tajima: "Reserch of micro

hydraulic power generation",2001 National Convention Record, IEE

Japan,Vol.7, pp.3099（2001-3）

[2] T. Mori, K. Itako, and T. Kimura: "Practical Use of small Scale（about 1kW

）Hydroelectric Power Generation in Consideration of Environment",2002

National Convention Record, IEE Japan,Vol.7, pp.134（2002-3）.

[3] Y. Kainuma, K. Yukita, Y. Goto, and K. Ichiyanagi: "A Basic Study of

Micro Generator by changing Number of Poles", 2006 National

Convention Record, IEE Japan,Vol.6, pp.32（2006-3）

[4] C. Marinescu, L. Clotea, M. Cirstea, I. Serban, C. Ion: "CONTROLLINGVARIABLE LOAD STAND-ALONE HYDROGENERATORS",

IECON, pp.2554-2559 (2005)

[5] S. Ogasawara, H. Funato, H. Takakamo, K. Kunio, K. Kazuo, T. Kobayasi:"Fundamental Experiment of a Micro Hydroelectric Power Generation

System Using an IPM Synchronous Generator", IEEJ-IAS Technical

Meeting on Semiconductor Power Converter, SPC-07-59（2007） [6] T. Sakurai, H. Funato, S. Ogasawara, K. Kunio, K. Kazuo, T.

Kobayasi:"Fundamental Experiment of a Siphon Type MicroHydroelectric Power Generation System Using an IPM Synchronous

Generator", IEEJ-IAS Technical Meeting on Semiconductor Power

Converter, SPC-08-84（2008）

[7] H. Takada and S. Ogasawara: "A Position-Sensorless IPM Motor Drive

System Using Field Prgramble Gate Array With CPU Core", IEEJ-IAS

Technical Meeting on Semiconductor Power Converter, SPC-04-28（2004

）

hydro turbine model

Fig.10. One example of simulation

micro hydro testing

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