R
There is an on going debate about the use of 1-E vs 3-E Drum level control in power boilers.
The debate is that 3-E control is only useful in conventional boilers where the heat input is changing. 1-E is all that is needed when the process change is in the steam flow only such as a combined cycle plant where the steam turbine load changes.
The side that states the above claims that when the steam turbine control valves open the drum swells and the steam flow increases, which in 3-E would add more water and trip the unit.
I contend that this first order zero is temporary and that 3-E increases stability IF that zero is taken into account in tuning the controllers.
I would like other to comment on there experiences with using 1-E and 3-E and see where this leads.
Thanks,
Ron
The debate is that 3-E control is only useful in conventional boilers where the heat input is changing. 1-E is all that is needed when the process change is in the steam flow only such as a combined cycle plant where the steam turbine load changes.
The side that states the above claims that when the steam turbine control valves open the drum swells and the steam flow increases, which in 3-E would add more water and trip the unit.
I contend that this first order zero is temporary and that 3-E increases stability IF that zero is taken into account in tuning the controllers.
I would like other to comment on there experiences with using 1-E and 3-E and see where this leads.
Thanks,
Ron