
Manual 35116
505HT for Pelton Turbines
Woodward
46
Figure 3-1. Nozzle Limit
When a stop command is issued, there are some actions that can be taken:
1. If the generator Breaker is opened a command to close deflector will be issued, the nozzle limit will
decrease to zero, all nozzles in use will decrease to zero and the turbine will stop.
2. If the generator breaker is closed the nozzle limit will decrease to zero, all nozzles in use will
decrease to zero. When the load is less than the unload trip level a command to open breaker will be
issued (if used). When the breaker opens a command to close deflector will be issued and the speed
will still decreasing until zero.
3. If open breaker function is in use and the Nozzle Limit reference goes less than Speed no load for a
configured time before the load reaches unload trip level the command to open breaker will be
issued.
When an unload command is issued, there are some actions that can be taken:
1. If the generator breaker is opened, no action will be taken
2. If the generator breaker is closed the control will be forced to go to load droop mode and the load
reference will be reduced to unload trip level. When the load is less than the unload trip level a
command to open breaker will be issued (if used). When the breaker opens the turbine will keep
running at rated speed.
3. If open breaker function is in use and the load reference goes less than load trip level for a configured
time before the load reaches unload trip level the command to open breaker will be issued. When the
breaker opens the turbine will keep running at rated speed.
See Appendix F, Figure F-1 for additional detail of Nozzle Limit
Speed Signal Processing
The 505HT for Pelton turbines has two speed signal inputs, but only one speed signal is required. Using
the second speed signal provides redundancy. If one speed signal fails, the control sends out an alarm
but does not shut the unit down, if the other speed signal has not failed. When both speed signals are
used, the speed signals are passed through a high signal select bus. At least one speed input must be
configured either for MPU or Proximity Probe.
The Control accepts any sine wave or square wave provided by a speed sensor that is proportional to the
speed of the turbine. This can come from magnetic pickups, proximity switches, and active pickups or
directly from generator voltage (in this case a PT should be used to decrease the voltage).
Released
Содержание 505HT
Страница 23: ...Manual 35116 505HT for Pelton Turbines Woodward 21 Figure 2 2 505D Outline Drawing Released...
Страница 196: ...Manual 35116 505HT for Pelton Turbines Woodward 194 Figure F 10 Deflector Logic Released...
Страница 197: ...Manual 35116 505HT for Pelton Turbines Woodward 195 Revision History New Manual Released...
Страница 198: ...Manual 35116 505HT for Pelton Turbines Woodward 196 Declarations Released...