Turbine

Tripping the turbine (from Base Load or ANY load, even unloaded!) occurs when:

1) A serious condition was detected by the turbine control system that required immediately closing the fuel supply valve

2) The fuel supply dropped below that required to maintain operation (flame cannot be maintained); this will usually be preceded by a drop in load as fuel supply decreases

3) An Emergency STOP pushbutton was actuated

4) An external system sent a TRIP signal to the turbine control system

Condition 1 could be the result of problems with field devices, wiring or even printed circuit cards in the turbine control system.

If some serious conditions occurs to cause the generator breaker to be opened, the turbine doesn't need to be tripped. It MIGHT trip on overspeed, but simply opening the generator breaker (called "tripping the breaker") IS NOT always accompanied by a turbine trip. Some generator or transformer conditions require that the turbine be shut down at the same time as the generator breaker is opened ("tripped")--but not always.

IF the unit has a digital Mark* turbine control system, there will be an Alarm Printer and some kind of Alarm Display on the operator interface that SHOULD indicate the cause of the trip. UNFORTUNATELY, GE turbine control systems have not included a "first-out" trip indication, and sometimes two or more conditions can be detected AFTER a trip--and they will be alarmed (printed or displayed on the Alarm Display) and that can complicate trying to understand what tripped the turbine.

Just about any operator SHOULD know how to use the Alarm Printout (IF the Alarm Printer is even working...!) and the Alarm Display. Many GE turbine control HMIs also have a "TRIP DISPLAY" that can be consulted after a trip to indicate all the trip conditions that were detected (again--lack of a "first-out" filter sometimes makes this difficult; more difficult than it should be). But, that's the place to start--either the Alarm Printout and/or the Alarm Display, and if the HMI has a TRIP DISPLAY it can be accessed and reviewed to see (most) all of the conditions that would result in a turbine trip.
 
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