Water and Energy Abstracts
Year : 2004, Volume : 14, Issue : 1
First page : ( 23) Last page : ( 24)
Print ISSN : 0021-1672.

55. Recent Pelton Turbine Upgrading Techniques

Risberg S., Haugen J.O., Rommetveit O., Bjerke M.

(Proceedings, Hydro 2003, Vol. I, Croatia, pp. 139–145).

Abstract

By utilisation of several new techniques, GE Hydro has gained new and valuable technical know how in the growing service and rehabilitation market for Pelton turbines. This brings along that Pelton turbines can be optimised using the newest turbine runner designs with tools that helps optimising the interplay between new and existing components in the turbine and thus exploit the fully performance potential of the unit. The techniques described in the paper are carried out in an ongoing upgrading contract for 12 Pelton turbines to four power stations owned by Statkraft, the largest power producer in Norway. For the customer, this process assures a high return on investment due to optimised hydraulic performance, shorten manufacturing cycle time and increased reliability due to robust engineering and manufacturing processes. The conclusions after utilisation of the different techniques described in this paper can be summarised as follows: Model tests offer a possibility to both study and measure interaction between components not easily gained from prototype inspections and efficiency tests alone. Accurate capturing of all relevant existing turbine geometries, actual alignments and clearances are important inputs to enable best possible adapted new designs and thus exploit the fully potential in the upgrading of the turbine. Model testing of turbines originated from five different turbine producers have given new and valuable information about the influence from turbine design on model to prototype efficiency scale-up prediction. It is concluded that direct use of formulas in Appendix K of the latest IEC60193 may lead to incorrect prototype performance expectations. It is evident that this incorrectness is strongly dependent on differences in turbine design philosophy. It is concluded that different design may cause different internal flow phenomena, which is not fully covered by the proposed formulas. Profitable use of model testing as a part of the turbine upgrading process is evaluated against the possibility to achieve increased improvements in the turbine performance. It will also demonstrate the capability of reaching the guaranteed prototype hydraulic performance. Whether using homologous or semi-homologous models are based on loss analysis of the relevant turbine components and a subsequent cost/benefit evaluation of the two alternatives. The “ParaPel” multi-parametric design optimisation technique has given improvements to the overall Pelton runner design and production process.

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Keywords

New techniques, Pelton turbines, Runner designs, Interplay, Exploit, Upgrading, Hydraulic performance..

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