Woodward 505HT, Инструкция по установке и эксплуатации

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Manual 35116 505HT for Pelton Turbines
Woodward 53
When Creep inputs have been configured, the Control will start looking for the following conditions:
•
The unit is given a “Stop” command
•
The speed has decreased below the 2%
•
All nozzles are closed
•
Generator breaker is opened
After all the above conditions are met and the “Dead Stop Time” has expired the Creep logic starts
looking for undesired turbine movement. Once a creep is detected, the control will stay in the alarm
condition until the “Reset Creep Time” expires. The Control will look for creep again when the “Look
Again Time” has expired.
The Creep alarm is sent to the general governor alarms and to Modbus. A configurable relay outputs can
be configured to energize upon a Creep Detection.
Overspeed Test
When the overspeed test is enabled, the electronic overspeed trip is disabled, the isochronous speed
reference ceiling is raised to “Overspeed Test Limit” and the raise/lower rate on the isochronous speed
reference is increased to configurable rate.
To perform the overspeed test, the following permissives must be met:
•
The unit is given a “Run” command
•
The speed has increased above 97%
•
Generator breaker is opened
•
All nozzles must be in Automatic Mode
Then the speed reference can be raised until the unit trips from the mechanical overspeed. If the
mechanical overspeed device does not trip the unit, the speed reference will have to be manually lowered
or the unit can be tripped manually to prevent a trip if the test is disabled and the speed is greater than
the overspeed limit. If the test is forgot enabled it will be disabled automatically after the “Time to Disable
Test” expires. When the test is disabled the following things can happen:
•
If the actual speed is above the “Overspeed Level” for at least the “Overspeed Delay” the unit will trip
•
If the actual speed is between the “Maximum Speed Reference” and “Overspeed Level” the speed
will be ramped back to the “Maximum Speed Reference”
•
If the actual speed is below the “Maximum Speed Reference” no speed action is taken
When this test is performed, there is NO internal overspeed
protection in the Control. If the mechanical overspeed device does
NOT trip the unit, the speed reference will have to be manually
lowered below the “Overspeed Level” or the unit can be tripped
manually.
To prevent possible serious damage or injury from an overspeeding
engine, be prepared to make an EMERGENCY SHUTDOWN when
performing this test, to protect against runaway or failure of
mechanical or other secondary overspeed devices.
Valve Driver
The Control's valve driver can be configured for many different applications. The valve driver (actuator
output) can be configured as a proportional signal or as an integrating signal.
For explaining purposes let’s suppose that the actuator output has been configured for 4–20 mA.
A proportional signal is a 4 to 20 mA signal that is proportional to the actuator set point, 0 to 100%. The
proportional signal is 4 mA for 0% nozzle position, 12 mA for 50% nozzle position, and 20 mA for 100%
nozzle position. No gain or offset adjustments are available in the Control when a proportional signal is
supplied due to the nature of the signal.
Released