Woodward 505HT, Инструкция по установке и эксплуатации

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Manual 35116 505HT for Pelton Turbines
Woodward 56
Small System Detection / Black Start
When the turbine is in parallel to the grid it may be desirable to detect if the turbine is in island mode. This
algorithm has this function. In order to do it monitors the turbine speed (when the turbine is in parallel to
the grid) and verifies if both the speed and its derivative value are within configurable windows. In case
either one of these parameters is outside its configurable window the controller automatically send a
disable Baseload, disable Level, and/or disable Remote Speed control. Therefore the unit will stay in
droop mode (load or position). In this case, as the unit is in not in a large system anymore a second set of
on-line PID adjustments are available. The control also issues an alarm.
If any control mode is enabled (baseload, remote baseload level, remote level or remote speed) the small
system will be disabled. The control can go to small system and back to large system voluntarily via either
Modbus or display commands.
Before starting the turbine it’s possible to set it for black start. If the unit is set for black start as soon as
the generator breaker closes the control jumps to small system mode. After that the same premises to
send the control back to large system are applicable.
Local / Remote
The control provides a local/remote feature. When local/remote discrete input is not used any
configurable discrete input and Modbus commands are accepted at any times. If local/remote feature is
used we have the following:
•
If we are in Local mode Modbus commands are NOT accepted
•
If we are in Remote mode discrete inputs commands are NOT accepted
•
Display commands are accepted at all times
Even if Remote mode is enabled a specific Modbus port (there are two Ethernet and one serial) can have
its commands (analog and Boolean writes) suppressed via configuration of the referred Modbus port.
Nozzle Sequencing
If a turbine has multiple nozzles the control can be optimized to not use them at all times. In order to do
that the control provides a way to “start” and “stop” the nozzles sequentially depending on the turbine
load/position setpoint. Nozzle #1 is always active and the other nozzles (up to 6) have and “ON” and
“OFF” configurations do define a load setpoint at with the referred nozzle is added or subtracted from the
control. For any given nozzle the “ON” value should greater or equal the “OFF” value. The “ON” and
“OFF” adjustments are thought in terms of:
•
Baseload setpoint if the control is in Baseload Mode
•
On-line setpoint if the control is at any other control mode, such as Level or pure droop mode. This
setpoint might represent load setpoint or average position setpoint depending if load droop or position
droop is enabled
Any time a given nozzle is requested to “start” it goes on a configurable ramp, given by “Open Time” until
and it takes part of the nozzle load sharing. This demand/flow equalizer between nozzles is done by the
“Load Share Gain”.
The equalizing nozzle demand logic compares the actual nozzle position (for each nozzle in operation)
with the desired demand and scale this error by the “Load Share Gain”. This error is then added to the
referred nozzle demand. This process is done all the time in order to make the nozzle demand equal for
all nozzles.
Any time a given nozzle is requested to “stop” the control starts to count down an internal timer and after
that timer expires the referred nozzle starts to close at a configurable rate, given by “Close Time”. The
remaining nozzles will stay in load sharing mode and will adjust their demands to compensate for this
nozzle going off.
Released