AVR Auto control swings

We operate a baseloaded steam turbine. Lately we have been experiencing load control swings when our AVR is in Automatic. We find ourselves placing the AVR in manual until the load settles out and then restoring back to automatic mode. We have been sending trends to our OEM for months with no identification as to why this is happening, the causes or solutions. We are replacing our AVR's in 6 weeks and am hoping this resolves the issue. Is there anything else we should be looking at?
 
We operate a baseloaded steam turbine. Lately we have been experiencing load control swings when our AVR is in Automatic. We find ourselves placing the AVR in manual until the load settles out and then restoring back to automatic mode. We have been sending trends to our OEM for months with no identification as to why this is happening, the causes or solutions. We are replacing our AVR's in 6 weeks and am hoping this resolves the issue. Is there anything else we should be looking at?
What kind of utility/facility is it?

Which mode do you see there is load swingings in the PF Volt/Var control modes??

Can we know more on OEM Steam turbine /generator /AVR and associated grid ..

Is there kind of PSS need to be tuned and activated during transients modes/times ...
Many questions and advises can be related to this specific case.

Tell us more by answering these questions then we can try to support !

James
 
What kind of utility/facility is it?

Which mode do you see there is load swingings in the PF Volt/Var control modes??

Can we know more on OEM Steam turbine /generator /AVR and associated grid ..

Is there kind of PSS need to be tuned and activated during transients modes/times ...
Many questions and advises can be related to this specific case.

Tell us more by answering these questions then we can try to support !

James
This is a biomass facility, one boiler one turbine. It is an Alstom turbine with a WEG generator. There is no PSS system associated with this unit. The loads appear to swing in both the voltage and var modes. We did have our PT's and taps serviced last fall. We saw no issues for approximately 2 months. We are not seeing any swings in the grid either.
 
This is a biomass facility, one boiler one turbine. It is an Alstom turbine with a WEG generator. There is no PSS system associated with this unit. The loads appear to swing in both the voltage and var modes. We did have our PT's and taps serviced last fall. We saw no issues for approximately 2 months. We are not seeing any swings in the grid either.
Okay.

Are you saying that the Facility is connected to a infinite grid ...
No swings in the grid... doesnt means that your AVR and associated equipment is well tuned ...

James
 
No it is not infinite, I am only saying we are not seeing the local grid swinging that would cause our AVR's to swing. Lat evening it go so bad we were forced to run our AVR in manual. It still swings in manual and auto mode.
 
No it is not infinite, I am only saying we are not seeing the local grid swinging that would cause our AVR's to swing. Lat evening it go so bad we were forced to run our AVR in manual. It still swings in manual and auto mode.
Okay i was just also saying that your AVR may be not tuned properly to get that swings damped or at least avoid such event ...

Did you get a system/grid stability studies done ? during design /engineering of the Plant..

We may need to get some trends on that event so we can offer better help!

Is there any nuisances alarms/trips log event related to this swings ...

If yes it would be helpful to share them here...*

Thanks for sharing such case ...we may support you on how to avoid such nuisances..

James
 
Is it a PID control system?
If it worked ok before, there can be something wrong with either the feedback measurement (partially broken/too slow) or the response of the process actuator (i.e. broken heating element in a heater).
 
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