Woodward 2301E-HT, Руководство по эксплуатации продукта

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Manual 35092 2301E-HT Hydro (Francis Turbines)
Woodward 19
Sometimes it is not desirable to have the unit responding to these slight frequency fluctuations. The
speed deadband can be enabled and the deadband window adjusted accordingly. When the speed
deadband function is set up, there are three options. The speed deadband function can be enabled at all
times, disabled at all times, or only when the unit is online.
Off-line/Isochronous Speed Control
The 2301E-HT control for Francis turbines has two PID control algorithms, an on-line/droop algorithm and
an off-line/isochronous algorithm. When the unit is off-line or in isochronous on-line control, the Off-line/
Isochronous algorithm is used. The Off-line/Isochronous algorithm controls the turbine speed to a set
point determined by the operator. The droop setting does not affect off-line or isochronous control.
For example, if the unit is off-line and the operator adjusts the set point to 95% rated speed, the 2301E-
HT will position the gates appropriately to control the turbine speed at 95% rated speed. If the operator
raises the set point to 100% rated speed, the control reacts by opening the gates and raising the turbine
speed to 100%. The operator can synchronize the turbine to the system and close the generator breaker.
The control functions exactly the same way when the turbine is on-line and in isochronous control
(isochronous controls means that the unit is acting as a slave of a load controller).
When the control is given a Start command, the control pre-
positions the speed set point to the “Speed-
No-Load Ref
.” The speed set point can be adjusted from the Raise and Lower discrete inputs, or Modbus.
The r
ate at which the set point changes is configured as the “Off-line/Isoch Raise/Lower Rate.” (This rate
is in percent of rated speed/second) The high and low limits for the speed set point are set up as “Upper
Limit-
Ref” and “Lower Limit-Ref.”
The speed set point follows actual speed when the turbine is on-line and not in Isochronous control, or
when the turbine is off-line and in Manual or Auto-Follow control. This provides a bumpless transfer into
Off-line or Isochronous control.
When the generator breake
r opens, the speed set point returns to the “Speed-No-Load Ref.”
The 2301E-HT digital control has two sets of PID gains, off-line and on-line. The only difference between
off-line control and isochronous control is that the off-line gains are used during off-line control and the
on-line gains are used during isochronous control.
When the off-line/isochronous PID algorithm is in control, a temporary compensation function is available
to help dampen any control instability. The PID gains should be tuned properly for optimum control
response before the “Temporary Compensation” is adjusted. The temporary compensation acts much like
a mechanical dashpot. As the gates open or close, the speed set point is temporarily lowered or raised
depending on the speed of the gates to slightly dampen the control
’s response.
When a Synchronizer/Load Control unit is used with the 2301E-HT, the speed reference in the internal
ramp of the control is fixed to 100%, so the final speed reference becomes 100% ± Speed Bias, and the
off-line/isochronous PID algorithm is used to control the unit. The Synchronizer/Load Control unit controls
the turbine by biasing the fixed speed set point through the Synchronizer/Load Control signal input. The
Synchronizer/Load Control signal input can
be scaled by the “SPEED BIAS ANALOG GAIN” in the
2301E-HT. The Synchronizer/Load Control speed set point biasing is ignored by the 2301E-
HT if it isn’t
being used with a Synchronizer/Load Control unit, if the speed is not stable, or if the unit is on-line but not
in Synchronizer/Load Control.
On-line/Droop Speed Control
The On-line/Droop PID algorithm is used when the unit is on-line and in Level Control, Remote Reference
Control, or Droop Speed Control. The On-line/Droop PID algorithm allow the unit to be paralleled with
other units and still remain stable. The droop value, the droop speed set point, and the turbine speed,
together determine how far the gates move, or how much load the turbine picks up.
For example, if the speed is fixed at 100% rated speed and the droop is set to 5%, a 1% droop speed set
point change will move the gates 20%. If the droop is set to 3%, the gates will move 33.3% for a 1%
change in the droop speed set point. The speed is always being monitored and reacted to by the control,
but the control will only respond by an amount determined by the droop setting. For example, at 5% droop
Released