| The The Pine Valley Hydro Plant was originally constructed
in 1941 and provided power to St. George until 1981. The plant sat idle
for a number of years - and was rebuilt on the same location (7 miles North
of the city on a culinary water line) and was rededicated in May 1995. The
maximum output is 600 kW from an induction motor that is turned by a dual
nozzle Pelton Wheel Turbine. The rated flow is 10.5 CFS which is 4712.4
GPM. This type of turbine requires high pressure to be efficient and the
system uses a head box 2 miles up the line that is controlled by a Programmable
Logic Controller (PLC). The PLC maintains 6' of water in the head box and
has a 900' drop in elevation which creates 450 PSI at the plant. The PLC
also changes the nozzle opening depending on the water flows to maintain
that 6' in the head box, when the flow increases the nozzle opens to compensate.
If there is an interruption in power, the plant is programmed to maintain
water flow. The nozzles will freeze where they were running and a by-pass
valve opens to keep the precious water flowing to St. George residents. |
| Click on picture for larger image |
Pine Valley Hydro |
In line view of Pelton Wheel
Turbine housing & Generator
drive coupling |
Side view showing nozzle
positions: #1 at top, #2 down
in recess in floor |
Control panel in control room |
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