April 9-10, 2014

REFURBISHMENT OF MEDIUM HEAD FRANCIS TURBINES

-TUNGATINAH CASE STUDY-

Congrès SHF : «Enhancing Hydropowerplant facilities», Grenoble

Joseph VIRONE, Anne CUVILLIER, Celine GARNIER, Nicolas JUHEL Claude BUCHI

© ALSTOM 2013. All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided without liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authority, is strictly prohibited.

Presentation title - 29/04/2014 – P 2

TUNGATINAH CASE STUDY Location : Tasmania, Australia

Site Location

Hobart

© ALSTOM 2013. All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided without liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authority, is strictly prohibited.

Presentation title - 29/04/2014 – P 3

Power station description

• Five vertical shaft Francis turbines, designed for 28 MW limited to 26,1: vibrations.

• Turbine are of Boving design, directly coupled to a GE generator.

• Each turbine has a spherical inlet valve and a relief valve discharging directly from the spiral casing.

• The generating sets were first installed and put in operation between 1953 and 1956.

Design characteristics : • Rated output at 289.56 m net head:

26.100 MW Corresponding flow at rated output:10.36 m3/s

• Maximum output: 28.076 MW (37 650 BHP)

• Rated speed: 600 rpm • Maximum runaway speed: 1050 rpm

© ALSTOM 2013. All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided without liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authority, is strictly prohibited.

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Objectives of the refurbishment- 3 units

• HYDRAULIC

• MECHANICAL

• ENVIRONMENTAL

• SAFETY

© ALSTOM 2013. All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided without liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authority, is strictly prohibited.

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Site measurements - performances

CALCULATED EFFICIENCY CURVE

Efficiency

+1,5/2,5 %

Max output 31

MW

Designed for 28

Limited to 26,1

© ALSTOM 2013. All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided without liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authority, is strictly prohibited.

Presentation title - 29/04/2014 – P 6

TURBINE SECTION Turbine general cross section

Air axial valve

Distributor

New components :

• Spiral case

• Distributor

• Lower guide bearing

• Turbine bearing & Shaft

seal

• Turbine shaft

• New coupling bolts with

Gen shaft

• Runner with coupling

• Air axial valve at the top

• New Servomotor for PRV

© ALSTOM 2013. All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided without liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authority, is strictly prohibited.

Presentation title - 29/04/2014 – P 7

Replacement of spiral case

Existing spiral case Existing spiral case dismantling Existing spiral case evacuation

New spiral case : installation New spiral case : concreting

Exceptionnal replacement

© ALSTOM 2013. All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided without liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authority, is strictly prohibited.

Presentation title - 29/04/2014 – P 8

Pressure relief valve solution

Existing pressure relief valve with mechanical link to the

operating ring

New servomotor for oil transfert

© ALSTOM 2013. All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided without liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authority, is strictly prohibited.

Presentation title - 29/04/2014 – P 9

Distributor – new design for medium head Francis turbines

Distributor before refurbishment

Distributor top view during

installation

One of the servomotors

Distributor with turbine shaft Distributor during trial assembly at

woorkshop

© ALSTOM 2013. All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided without liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authority, is strictly prohibited.

Presentation title - 29/04/2014 – P 10

RUNNER

Runner during dynamic balancing

Runner during dye

penetrant test Runner at workshop

Old runner

Single casted parts:

- 17 blades

- Less than 3 t

- Outlet dia 1135 mm

- Dynamically balanced

Casting advantages :

• Reduced delivery time.

• Solves the welding access problem for

small runners.

• Suppresses the risk of weld defects.

European foundries with :

• High tec process

• Very accurate model 5 axis machining

• Overthicknesses reduced

• Until to 5 m

© ALSTOM 2013. All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided without liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authority, is strictly prohibited.

Presentation title - 29/04/2014 – P 11

AIR AXIAL VALVE

View from the installation bay

Air axial valve : cross section

The air valve is fully integrated in

existing cover.

• aeration through the shaft line • automatic with possibility to be piloted. • This arrangement improves unit stability.

© ALSTOM 2013. All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided without liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authority, is strictly prohibited.

Presentation title - 29/04/2014 – P 12

Hydrostatic water bearing

Compact

stiffen

Maintain the shaft in position: spring effect

Compact

Stiffen

Wearing rings gaps optimized

© ALSTOM 2013. All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided without liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authority, is strictly prohibited.

Presentation title - 29/04/2014 – P 13

Full assembly behavior checked by finite elements calculation

Hydrostatic water bearing deflection

The max allowable deflection transmitted by the structure, through the head cover, to the hydrostatic bearing was calculated using finite elements method.

© ALSTOM 2013. All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided without liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authority, is strictly prohibited.

Presentation title - 29/04/2014 – P 14

Hydrostatic water bearing

Hydrostatic turbine water bearing in reverse position

Turbine shaft & sleeve with ceramic coating

New automatic strainer 50µm

© ALSTOM 2013. All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided without liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authority, is strictly prohibited.

Presentation title - 29/04/2014 – P 15

Lower generator bearing

© ALSTOM 2013. All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided without liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authority, is strictly prohibited.

Presentation title - 29/04/2014 – P 16

CONCLUSIONS

Finally we can retain :

- efficiency & output > increased

- limitation due to vibrations removed

- CFD expectations confirmed

• Major innovation has been used : hydrostatic water bearing

• rare replacement has been performed : embedded spiral case

• Unit instabilities have been suppressed ( new air axial valve )

• Environment has been preserved thanks to the new hydrostatic water bearing.

• Safety of the power plant has been increased

suppressing oil vapour contamination ( lower bearing)

using modern & simplified distributor design and failure detection

Using new oil transfert operating mode for pressure relief valve

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