Page 279 - Design of Solar Thermal Power Plants

4.4 CONTROL DESIGN OF THE HELIOSTAT FIELD 261

FIGURE 4.23 Heliostat tracking deviation correction control of the Badaling solar ther-
mal power plant.

of times for deviation correction can be modified on the “System
Maintenance” page.
Definition of range of deviation correction: when the absolute
value of the deviation is less than the lower limit of this range, it
means the respective deviation correction is qualified.
Once the heliostat has reached the deviation correction point, the
deviation correction camera is initiated. In the case where the
absolute value of the deviation is less than the lower limit of the
deviation-initiated range, the deviation-initiated process finishes,
and the azimuth deviation angle and elevation deviation angle are
recorded as the corrected values of X and Y separately in the
database while recording the completion date and time of deviation
correction.
In the event that the absolute value of deviation is greater than
the upper limit of the deviation correction range, and the number
of deviation corrections is less than the maximum number of
deviation corrections, new coordinates are calculated based on the
current deviation and sent to the heliostat control system; when the
heliostat once again reaches the deviation correction point, the
camera is initiated. In the event that the absolute value of deviation