Environmental Engineering Reference
In-Depth Information
Figure 4-5. Typical electrical one-line diagram for a grid-connected wind turbine.
of improper electrical connectors has caused significant machine downtime. Many commer-
cial developers have used step-up transformers with marginal ratings, and failures of these
components have been a problem at some wind power stations. Generator failures, such as
short circuits and overheating, have sometimes occurred and are usually caused by moisture
in the windings. Today's generator designs generally employ heaters and temperature sen-
sors in the windings to prevent these problems.
Control and Monitoring Systems
Nearly all commercial wind turbines employ a
system control and data acquisition system
(SCADA) with a
microprocessor
to control wind turbine operation and monitor performance.
Most new wind power stations are equipped with central monitoring and control, in which an
on-board microprocessor
in each wind turbine sends performance and machine status informa-
tion to a
central computer
equipped to constantly monitor and record these data. Automatic
alarms are widely used to notify an operator of a wind turbine or utility line problem. Most
of the problems encountered with microprocessor controls have been related to the associated
software programs. The onboard microprocessor generally controls the following functions:
-
cut-in
and
cut-out
wind speeds (defining the operating range)
-
connection of the generator output lines to the grid
-
nacelle orientation (active yaw systems)
-
blade pitch angle (active pitch systems)
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