Oliver PaishDerwent Hydro

Technical innovations in low head hydro

Siphon Propeller Turbines operating at Variable Speed

DTI R&D Project

Title:Siphon Propeller Turbines operating at Variable Speed

Partners:

IT Power

Derwent Hydro

GP Electronics

Reading University

Funding:

60% DTI

40% Project team

Background : Low-Head Hydro

High head hydro is the most economic -but the least available

The UK has an abundance of low-head sites at existing mills and river structures

But few low-head projects have proceeded in recent years

Site layouts

Historical Roots

Weirs and Sluices

Today’s technology

Turbine configurations as head reduces

HEAD

Project Rationale (1)

1. Siphon design:

Creates extra height to fit the turbine, eliminating excavation works

System shutdown by breaking the siphon

Turbine and generator both above upstream water level

Supplied as a complete pre-assembled unit

Project Rationale (2)

2. Variable-speed control:

For use with a simple, fixed-geometry turbine

Ensures maximum power achieved at all times

Vary speed to match changing head

Flow control without complex mechanisms

Project Phases

3D Hydraulic analysis of siphon shapes

Detailed mechanical and hydraulic design

15kW prototype construction

Sourcing and adaptation of variable-speed control unit

System installation at Borrowash, Derby

3-month test programme

Pow e r Ltd

Propeller runner

Guide vanes

Turbine and draft tube

Belt-drive and generator

Variable-speed control unit

Variable-speed concept

Input: 0 - 100 Hz

Output: 50Hz, 240V

Power vs speed characteristic

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

0 50 100 150 200 250 300 350 400 450 500 550 600 650 700 750 800 850 900 950 1000

Runner RPM

Pow

er (k

W e

lect

ric)

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

150 165 330 495 660 825 990 1155 1320 1485 1650 1815 1980 2145 2310 2475 2640 2805 2970 3135 3300

Generator RPM

Guide vanes at 20 deg (14-01-03).

Guide vanes at 10 deg. (24-2-03)

Flow vs Speed

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

0.45

0.50

0.55

0.60

100 150 200 250 300 350 400 450 500 550 600 650Normalised Speed

Norm

alis

ed F

low

Test Data

Runner Data

Efficiency

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

0.45

0.50

0.55

0.60

0.65

0.70

0.75

100 150 200 250 300 350 400 450 500 550Normalised Speed

Effic

ienc

y

Test Data

Runner Data

Borrowash Mill, May 2003

THE END