Woodward 505HT, Инструкция по установке и эксплуатации

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Manual 35116 505HT for Pelton Turbines
Woodward 45
Functions
The functions of the 505HT for Pelton Turbines are described in detail in this section. The values that are
in “quotes” can be configured for the specific application. Configuration of these values is discussed in
greater detail in this manual.
External Start Permissive
An external start permissive is available when one of the configurable inputs is configured to do it. When
the unit is started up and the control resets, the start permissive contact must be closed before the unit
issue a governor run command.
Start, Stop, Unload and Nozzle Limit
When the Control is given a start command, once all shutdowns have cleared and the optional input
“Start Permissive” is true, if used, the deflector will open, the Nozzle Limit ramps at “start nozzle rate” to
the “Breakaway Limit”, and stays there for the “Hold at Breakaway Time” (see Figure 3-1). Since the
control does not have any speed signal yet, the nozzles will follow the Nozzle Limit. After the “Hold at
Breakaway Time” expires, the Nozzle Limit ramps to the “Speed-No-Load Limit” at the “Start nozzle
Rate”. It will remain there while the control is synchronizing. At some point during this sequence, the
turbine should reach its rated speed and the Control will start controlling speed. If the control does not
sense at least the “Start Speed” by the time the “Time to Start Speed” timer has expired, then the control
issues an emergency shutdown due to an incomplete start. In case the “Speed-No-Load Limit” is not
enough to make the turbine achieve rated speed within the “Auto Raise Timer” time the Nozzle Limit
value will increase at the “Auto Raise Rate” until the offline PID takes control of the nozzle demand.
When the breaker closes, the nozzle limit steps to the “Maximum nozzle Limit”.
If the unit experiences a load rejection, the nozzle limit will automatically step to the “Speed-No-Load
Limit”. If the load rejection algorithm is used the nozzle limit will step to the load rejection nozzle limit and
while the algorithm is running and then step back to the “Speed-No-Load Limit”.
All nozzle limit configurations shall be done in terms of turbine total
flow, not in individual nozzle demand. Therefore depending on the
nozzle sequencing configuration the actual individual nozzle demand
will be greater than the nozzle limit values.
Released