Coleridge G8 & G9

 

Coleridge G8 & G9

Click here for a PDF of the Coleridge G8 & G9 Project Sheet

DESIGN AND MANUFACTURING

Hydroworks was commissioned by TrustPower Ltd to redesign the two 1922 Escher Wyss cast steel Francis turbines at Coleridge power station to improve their efficiency and service life.

The new martensitic stainless steel runners were designed using computational fluid dynamics and the runner stresses were determined using finite element analysis.

OPERATION

Comparison of the tailrace of G8 post refurbishment and G9 pre refurbishment, both operating at the same power output of 3,000 kW,
shows significant reduction in turbulence indicating improved efficiency.

G8 also shows a weir height of 4.0 and steady versus a G9 weir height of 4.4 and fluctuating between 4.0 and 5.0. This difference in weir heights equates to a reduction in flow of 12% at the same power output.

Client: TrustPower Ltd
Location: Coleridge, New Zealand
Scope:
Replacement runner, seals, wicket gate wear plates and refurbishment of head covers and turbine shaft.
Head: 141.5 m
Discharge: 3.2 m3/s    
Nominal Output: 3,000 kW
Commissioning: 2008
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Original cast steel runner

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Redesigned martensitic stainless steel runner. 

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G8 after completion of refurbishment. 

 

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The adjacent G9 turbine in its original condition.

       

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G8 weir level at 3,000 kW    

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G9 weir level at 3,000 kW    

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G8 tailrace at 3,000 kW    

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G9 tailrace at 3,000 kW