Woodward 505HT, Инструкция по установке и эксплуатации

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Manual 35116 505HT for Pelton Turbines
Woodward 52
Figure 3-4. Pond Level Control Accuracy
The smaller the “Desired Control Accuracy” value is, the steeper the slope will be on the above graph.
This will result in a very high “gain” on the Nozzle position, and small error fluctuations in the Pond/Tail
Level will move the Nozzles very quickly. The “Desired Control Accuracy” value should be made as large
as possible for each given application.
If “Fixed Speed in Level Control” is used the nozzle position demand will not be compensated by the
turbine speed (grid frequency). In other words, it won’t follow the position droop curve and will stay
exactly at the nozzle demand given by the level control loop.
While in Level Control the load droop mode is forced disabled and cannot be enabled.
See Appendix F, Figure F-2 for additional detail on Level Control.
Step Test
During the initial calibration of the control system, the control loops must be calibrated for optimum
performance. Four step test logic are built into the control to aid in the tuning of the following PID’s:
•
Offline PID
•
Online PID
•
Baseload PID
All step tests follow the same logic: there’s an Enable command, an expiration time, a step
amount/magnitude and a Boolean to say if the step is positive or negative. There’s no need to disable the
step test. Once the time expires the step demand automatically goes to zero.
Creep
The Control can be configured to detect unit Creep. Two discrete inputs are required to use this function.
The inputs come from proximity switches focused on the speed gear. Preferably one proximity switch
should be centered on a gear tooth, and the other proximity switch should be centered on a gear trough
(or in between two gear teeth), however this approach is not mandatory for this logic to work. The Control
will detect a creep as slight as one gear tooth of rotation.
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