MICRO HYDROELECTRIC POWER PLANT WITH CHAIN TURBINE

Nguyen Minh Duy

Content

1. Overview about hydroelectric power plant2. Analysis chain turbine3. Governor using for chain turbine4. Work in the future

Hydropower to Electric Power

PotentialEnergy

KineticEnergy

ElectricalEnergy

MechanicalEnergy

Electricity

Hydropower to Electric Power

How Hydropower Works

Water from the reservoir flows due to gravity to drive the turbine.

Turbine is connected to a generator.

Power generated is transmitted over power lines.

How Hydropower Works (2)

A water turbine that cover the energy of flowing or falling water into mechanical energy that drives a generator, which generates electrical power. This is a heart of hydropower power plant.

A control mechanism to provide stable electrical power. It is called governor.

Electrical transmission line to deliver the power to its destination.

Vietnam Hydroelectric Potential

Vietnam Hydroelectric Potential (2)

Vietnam, the nation yearly average of rainfall is about 1,861mm.

There are more than 2,200 big-to-small rivers and streams. So Vietnam is rich hydropower resource.

Vietnam is agricultural country (agriculture: 20.1%). This is a goal to invest SHP.

Sizes of Hydropower Plants Pico hydroelectric plant

Up to 10kW, remote areas away from the grid Micro hydroelectric plant

Capacity 10kW to 300kW, usually provided power for small community or rural industry in remote areas away from the grid

Small hydroelectric plant Capacity 300kW to 1MW

Mini hydroelectric plant Capacity above 1MW

Medium hydroelectric plant 15 - 100 MW usually feeding a grid

Large hydroelectric plant More than 100 MW feeding into a large electricity

grid

Micro Hydropower Systems

Many creeks and rivers are permanent, they never dry up, and these are the most suitable for micro-hydro power production

Micro hydro turbine could be a waterwheel Newer turbines : Pelton wheel (most

common) Others : Turgo, Crossflow and various axial

flow turbines

Turbine Classified

Impulse Turbines

Uses the velocity of the water to move the runner and discharges to atmospheric pressure.

The water stream hits each bucket on the runner.

High head, low flow applications. Types : Pelton turbine, Turgo turbine

Pelton Turbine

Turgo Turbine

Reaction Turbines

Combined action of pressure and moving water.

Runner placed directly in the water stream flowing over the blades rather than striking each individually.

Lower head and higher flows than compared with the impulse turbines.

Francis Turbine

Kaplan Turbine

Turbine Selection Chart

Chain Turbine It is a gravity machine It is built up of two parallel

chain systems joint together at the chains with a series of buckets.

The flow rater entering the buckets is controlled by the water valve through a motor to open or close the valve.

Buckets fill full of water go down to bring to rotary sprocket system.

Analysis of the Chain Turbine

With flow rate is 1m3/s, and the head is 20m.

Assume H1=19m, H2=1m, the diameter of the sprocket is 1m.

Analysis of the Chain Turbine (2) The gross power output:

Apply the principle of work and energy with the bucket of chain turbine:

The maximum speed of bucket

The angular velocity the sprocket would be

The rotational speed of the sprocket would be

kWQgHP grossgross 1962081.911000

22

00 2

1

2

1tt mvmghmvmgh

12gHvt

sec/5.195.0

75.9rad

R

vop

rpmrpm 1862.1862

604.9

2

60

Analysis of the Chain Turbine (3)

Number of buckets

The volume of a bucket (m3)

8 0.50

10 0.40

12 0.36

Number of buckets in chain turbine

11

1 02.4)2(

QQv

QDHN

op

Analysis of the Chain Turbine (4)

The power output is

The power out of the turbine shaft

The efficiency of the chain turbine is given by

2opopout QvrQvTP

kWQvP opout 1.9575.911000 22

49.0196

1.95

kW

kW

P

P

gross

out

Analysis of the Chain Turbine (5)

Rotational velocity of sprocket depends on the distance of between two shafts of turbine H1.

Rotational velocity of turbine shaft is slow, so it cannot directly connect with generator. It need a power transmission

Efficiency of chain turbine is low.

Advantages of Chain Turbine

It is run-of-river power plant. Do not worry about the turbidity of water. There is no danger of cavitations. It is simple to construct, repaired and

maintenance.

Disadvantages of Chain Turbine

The slow rotation of chain turbine leads to high speed ratios when connect to generator at 600 rpm – 1500 rpm.

This chain turbine operation is very noise. Structure of turbine is very big

Governor

To maintain the generator at a constant 50Hz frequency, it is necessary to maintain the generator shaft at a constant rotational speed. In the independent hydroelectric power plant, the rotational speed of the micro hydro power generator can be change when loads are added or subtracted from the electrical system.

1200 pN

f

Governor (2)

The system frequency can be maintained constant by eliminating the mismatch between generator and load.

Governor is to receipt the frequency signal from the output of generator. And it is compared with standard frequency signal. From these results, governor output signal is coming-out to control the

valve of water at the entrance to the turbine.

Transfer Function Block Diagram of Hydro Plant

power system gain constant (Hz/p.u) nominal starting time of water in penstock (s) integral gain constant for servo system proportional gain controller constant for servo motor

PK

WT

ISK

PSK

Governor Transfer Function

Chain Turbine transfer function

water starting time at full load

So transfer function of chain turbine is

sT

sT

G

P

w

wm

5.01

1

wT sg

gH

LUT r

w 022.02081.9

121

s

s

sT

sT

G

P

w

wm

011.01

022.01

5.01

1

Generator Transfer Function

Assume nominal load Frequency 50Hz The latter load assumption yields

So, the system gain constant and time constant are given by

The transfer function of generator

kWPL 90

ssT

KSG

p

pp 22.21

55.55

1)(

sfD

HTP 22.2

018.050

122

upHzD

KP ./55.551

HzupkWHz

kW

fP

PD

R

L /.018.010050

90

Transient responses of system for step changes in load, showing deviations in system frequency

Transient responses of system for step changes in load, (1.5kW) for different integral gain value, showing deviations in system frequency (1)

Transient responses of system for step changes in load, (1.5kW) for different integral gain value, showing deviations in system frequency (2)

Transient responses of system for step changes in load, (1.5kW) for different integral gain value, showing deviations in system frequency (1)

Transient responses of system for step changes in load, (1.5kW) for different integral gain value, showing deviations in system frequency (2)

Governor Discussion

It is more flexible than classical governor. This governor effectively eliminate the

frequency deviations due to load disturbances for different nominal loadings of the system

It is importance as the saved water can be used for irrigation.

Work in the Future In China, YiuHwa Engineering Company is building a hydroelectric

power plant with chain turbine to experiment and research with capacity 200kW.

This plant has two turbines and built with head 20m and flow rate 1.03m3/sec