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Dieter Krompholz / VA TECH ESCHER WYSS GmbH / 1www.vatech-hydro.comsustainable solutions. for a better life.

THE CAT FROM VA TECH HYDRO

OVERVIEW

WHAT IS A CAT ?

HOW RELIABLE IS A CAT ?

WHAT FEATURES DOES A CAT HAVE ?

CAT COMPARED TO OTHER TURBINE CONCEPTS

TWO CATS IN SCANDINAVIA

CONCLUSION

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WHAT IS A CAT ?

CAT = Compact Axial Turbine

Part of modularized`Compact HydroTurbine programme

Turbine concept for smalland medium size HPP

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WHAT IS A CAT ?

Application range:

heads from 6m up toapprox. 30mflows up to 65 m3/s

Competes with:

S-Turbines andvertical direct-coupled KaplanTurbines

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HOW RELIABLE IS A CAT ?

First CAT sold 1987 in Spain

CAT as Compact Hydro concept launchedin 1992

Based on model tests from own laboratories

20 CATS sold CATS are running all over the world

Biggest CAT with 13 MW operating in Canada

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Three options for arrangement

Horizontal arrangement

Slant arrangement Vertical arrangement

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horizontal shaft position

usually 4-bearing-arrangement with intermediate shaft and flexible coupling

vertical shaft position 3-bearing-arrangement with axial thrust bearing ingenerator

modular concept allows fast installation on site

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water-lubricated radial guide bearing

Turbine bulb filled with water advantages for cooling and environment

wicket gate

guide vanestwo-side supported withlubrication-free bushes

safety spring element onevery second guide vane

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Standstill break to stop and hold the turbine after shut-down

coupling to generator usually direct-coupled is preferred

coupling via gear box also possible

excellent turbine efficiency level over 93% (up to over 94%) possible

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CAT COMPARED TO OTHER TURBINE CONCEPTSCAT vs S-Turbine

Horizontal S-Turbine

More excavation depth

Complicated pattern work for draft tube

Generator location above draft tube(possible difficulties if direct-coupled)

Horizontal CAT

Less excavation depth

Simpler pattern work for draft tube

Generator location below/besideintake pipe

CIVIL ENGINEERING

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CAT vs S-Turbine


Difficult access to oil feeder(located in bulb)

More complicated runner dismantling(due to removal of the shaft)

Horizontal CAT

Easier access to oil feeder

(located at generator)

Easier runner dismantling for CAT

MAINTENANCE AND SERVICE

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CAT vs S-TurbineEFFICIENCY AND POWER OUTPUT (for the same application)

Horizontal CAT

Tendency to better eta and power output no bend in draft tube

shaft position on intake side disturbsflow less


Tendency to lower eta and power output bend in draft tube

shaft position on draft tube sidedisturbs flow more

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CAT vs vertical Kaplan turbine

Vertical Kaplan

No major difference in excavation depth(similar draft tube)

Wider building and larger volume due towide spiral

Wider building for multi-turbinearrangement

Generator located lower

Vertical CAT

No major difference in excavation depth(similar draft tube)

Smaller building

Smaller building in a multi-turbine

arrangement Generator located higher

CIVIL ENGINEERING

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Vertical Kaplan

Easy access to generator

Difficult access to runner(removal of generator etc.)

Vertical CAT

Easy access to generator

Easy access to runner and wicket gate

SERVICE AND MAINTENANCE

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Vertical Kaplan

Tendency to lower eta and power output

more bends in flow direction

semi-spherical runner housing

Vertical CAT

Tendency to better eta and power output

just one intake bend

complete spherical runner housing

EFFICIENCY AND POWER OUTPUT (for the same application)

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Kongsfoss in Norway

Vertical CAT 1770

Customer: Modum Kraftproduksjon

Built in 2003

Flow:22m3/s, Head:15m, Power:2.9 MW

Approx. 15 GWh per year

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Tnger in Sweden

Horizontal CAT 1450

Customer: Fortum

Built in 2005

Flow:15m3/s,Head:34m,Power:4.6MW

Approx. 23 Gwh per year

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CONCLUSION

Compact Axial Turbine Concept is interesting

for small and medium Hydro power plants

for head range of approx. 6m to 35m

due to its high efficiency level (based on model tests)

due to its possibilities with regard to civil engineering

Documents

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