Woodward 505XT, Инструкция по установке и эксплуатации

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Manual 35018V1 505XT Digital Control System for Steam Turbines
Woodward 194
Fault 5
– Process movement greater than
Process Limit
This fault indicates that the process input exceed the
Process Limit
.
Some causes of this fault could be:

The
Response Timeout
is too long, the PID cannot increase the output movement fast enough to
counteract system drift.

The system is not at steady state. As an example, if the Integral Gain input is relatively low, there
could be a large error between process and setpoint.

The
Process Limit
is too low

The
Act Limit
is too high, resulting in actuator movements that are too large for the
Process Limit
(this is unlikely).
Some solutions for this fault would include:

Decrease
Response Timeout
if the system is much faster than the time-out

Proportional Gain could be adjusted to make the system stable, if applicable.

Integral Gain could be adjusted to allow system to minimize error and/or slow hunt, if applicable.

Process Limit
could be increased, if the turbine system allows

Check for excessive noise on the process input, check shielding and grounding on the applicable
sensors and actuator(s).
Fault 6
– Optimizer time-out
This fault indicated that the optimizer time exceeded the allowable time-out time, of 40 times the specified
Response Timeout
, or 20 cycles of movement.
Some causes of this fault could be:

The
Act Limit
is too low, this is the most common cause of this fault

The
Response Timeout
is too short for the process input response.

The system response is restricted, by low steam pressure, a partially closed trip and throttle valve,
etc.

The valve or actuator is against a stop or at the end of its travel, not allowing the PID to control the
process completely.
Some solutions for this fault would include:

The
Act Limit
could be increased.

The
Response Timeout
could be increased, if the system was still increasing/decreasing at the time-
out times.

The operating point (Setpoint) could be adjusted, if an actuator or valve is close to the end of its
travel.

The system variables should be checked, ensure that inlet pressure is high enough, hydraulic
pressure is high enough, the trip and throttle valve is open, etc.
Fault 7
– Droop input movement, greater than limit.
This fault indicates that the Droop input exceeded its allowable movement, similar to fault 5 for the
process input.
Some causes of this fault could be:

The
Response Timeout
is too long, the PID cannot increase the output movement fast enough to
counteract system drift.

There is noise on the Droop input

The system is not stable, the Droop input is moving around too much with respect to the
Droop Limit
input.

The system is not at steady state. As an example, if the Integral Gain input is relatively low, there
could be a large error between droop and setpoint.

The
Droop Limit
is too low.

The
Act Limit
is too high, resulting in actuator movements that are too large for the
Droop Limit
(this
is unlikely).