Powerful water in California
Two different American utilities have placed orders with VA TECH HYDRO for two power generating projects as a part of drinking water supply systems in southern California. One of the interesting aspects of these two projects is that much of the costly systems (piping/penstock, intake, bypass systems, access) are already in place, however the newly generated energy will guarantee a very short return on investment period.
Compact advantages
For the Palmdale project VA TECH HYDRO is to supply one horizontal Francis unit with overhung runner, electrical wicket gate servomotor and one induction generator. The general contractor, TURBOFLO in Pasadena, has ordered this new unit to replace a poorly performing reverse running pump currently installed in the existing powerhouse. The proposed unit is similar to a unit provided in 1998 for the Talbott project in Virginia, USA, thereby taking full advantage of the modular design of the Compact units.
Selecting what is right
At the Rancho Penasquitos plant, which belongs to the San Diego County Water Authority, the extremely long water supply system (35.5 km) requires a carefully selected turbine design having minimum flow change characteristics at runaway speeds. VA TECH HYDRO used an appropriate existing hydraulic profile and, to confirm its suitability, performed a complete transient analysis, including the model tested hydraulic behaviour of the turbine, prior the award of the contract.
The results of the calculations confirmed our design selection that the calculated flow variation at runaway speed can be kept within the tight acceptable range. The wicket gate closing time and the synchronizing time have also been checked and recommendations given to the customer. The supply to the general contractor, Archer Western Contractors Ltd, will include one horizontal Francis turbine with electrical wicket gate servomotor, one synchronous generator, the inlet valve and the erection and commissioning supervision. Delivery of the complete unit is planned in late summer 2005.
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