FAILED TO REACH FULL SPEED NO LOAD STAGE

We have a Taurus 60 generator turbine and in the start process is normal,but further up the compressor speed increases only up to 80% and trips off. The final stage which is the full speed no load is not archieved.
 
We have a Taurus 60 generator turbine and in the start process is normal,but further up the compressor speed increases only up to 80% and trips off. The final stage which is the full speed no load is not archieved.
Hi

Without getting/knowing datas/infos, such at least as:

1.Controls system model

2-Trip/alarms log event

We cannot make comments/advices, according to the for the" issue description" .
 
This is for GE GT Frame 6B and Mark VI system:

There is interstage pressure above 12 bar during start up so we bent from transmitter vent and kept below 6 bar so GT sequence running normal...after firing we close vent...
But GT not reach at FSNL,speed also Ok as required for FSNL(14HS indicated on display) is above interstage pressure issue effect on FSNL?
 
It would be necessary for you to tell us what Process- AND Diagnostic Alarms were present prior to reaching 14HS and what were present when the unit was at 100% TNH (14HS is usually 95% TNH--95% of rated speed, not 100% of rated speed). If it's reaching rated speed but not indicating it on the display, that could be (probably is) a different problem (see below). If you can't synch after getting to approximately 100.3% speed then something else is wrong and isn't being addressed (resolved).

12 bar in the interstage cavity is a LOT during firing and acceleration. The REAL problem during firing and acceleration is why is that pressure so high? Is 20PG-1 not working? Is the SRV leaking? Why is the pressure so high? P2 pressure SHOULD increase as TNH increases (the increasing P2 pressure assists with acceleration). P2 pressure should stay relatively constant once the unit reaches 100% TNH (which should also be the speed when the unit is synchronized to a grid with other units--a well-regulated grid, that is).

But to answer YOUR question about why the unit isn't reaching FSNL we need to know what speed it is reaching (either in TNH or RPM) and what alarms are present. What is the P2 pressure at the maximum speed the unit is reaching? What is the gas fuel supply pressure at the maximum speed the unit is reaching? What is the value of FPRG (the P2 pressure reference) at the maximum speed the unit is reaching? Is it just that the main display isn't saying the unit is at Full Speed-No Load? Are the Aux. Pumps (Lube Oil and Hydraulic) shut off when the unit is at the maximum speed it is reaching?
 
It would be necessary for you to tell us what Process- AND Diagnostic Alarms were present prior to reaching 14HS and what were present when the unit was at 100% TNH (14HS is usually 95% TNH--95% of rated speed, not 100% of rated speed). If it's reaching rated speed but not indicating it on the display, that could be (probably is) a different problem (see below). If you can't synch after getting to approximately 100.3% speed then something else is wrong and isn't being addressed (resolved).

12 bar in the interstage cavity is a LOT during firing and acceleration. The REAL problem during firing and acceleration is why is that pressure so high? Is 20PG-1 not working? Is the SRV leaking? Why is the pressure so high? P2 pressure SHOULD increase as TNH increases (the increasing P2 pressure assists with acceleration). P2 pressure should stay relatively constant once the unit reaches 100% TNH (which should also be the speed when the unit is synchronized to a grid with other units--a well-regulated grid, that is).

But to answer YOUR question about why the unit isn't reaching FSNL we need to know what speed it is reaching (either in TNH or RPM) and what alarms are present. What is the P2 pressure at the maximum speed the unit is reaching? What is the gas fuel supply pressure at the maximum speed the unit is reaching? What is the value of FPRG (the P2 pressure reference) at the maximum speed the unit is reaching? Is it just that the main display isn't saying the unit is at Full Speed-No Load? Are the Aux. Pumps (Lube Oil and Hydraulic) shut off when the unit is at the maximum speed it is reaching?
In addition to above checks, also check whether the compressor bleed valves are closed and their limit switches are indicating the same.
 
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