what will happen to gas turbine operation

[paktoon]

hello"
if we have two gas turbine and both are running in parallel, if we place both turbine in droop mode what will be the result, and if in ischo mode, then what will happen .is there will be any change in the frequency ? will both work in normal condition? what will be the ultimate result?

 

[peterb]

Both in droop mode, same droop setting = normal system operation, with frequency dependent on load (assuming the GTs are operating as an isolated island) and the two generators sharing load in proportion to speed setpoints; adjust frequency by adjusting speed controls of both GTs in turn to achieve desired frequency (or use automatic controller to achieve this)
Both in isochronous mode = unstable load sharing, unless additional load control mode is available & is selected; frequency will be steady
Try operating one machine in isochronous mode to set frequency and the other in droop mode. The droop machine will operate at a fixed load (assuming the frequency is maintained constant by the isoch machine); the isoch machine will take any load swings that may occur

 

thanks"
but when the both tuebine in droop mode and suddenly a 2MW motor starts then will there will b a frequency jerk,and and the load will be shared. and if the same situation occur to both turbine when in ischo mode and a 2MW MOTOR STARTS?

 

[tomatge]

Depending on the size of the GTs you are likely to experience a dip in frequency when you apply a step change in load, regardless of governor mode. The larger the size of the GTs in comparison to the load, the lower the frequency dip will be.
The effect of governor mode will determine the steady state (rather than transient) effect on frequency. If both machines are in droop mode, then increasing the load on the machines will cause a drop in frequency setpoint for the governors (this is what governor droop is). The way in which the load is shared between the GTs will depend upon respective droop settings.
If you run one machine in isochronous governing mode, then that machine will take up all load changes. The other GT will run at virtually constant load.
You should not run both machines in isochronous governing mode. There is a real danger of unstable operation of the machines in that condition.