DLN 2.6 Mode Transfer Temperatures
A common misunderstanding in operating the GE 7FA is actually “when” the unit transfers between operational Modes. In fact, the MKV determines when to change Modes based on a calculated combustion reference temperature (TTRF1) not at what MW load you’ve reached. You may hear someone speak of a transfer related to a specific load point… which is really only a rough estimate of where the unit may be when the controls determine the optimum point to fuel additional nozzles. Several variables may change the MW load at which the unit transfers, including ambient temperature, fuel gas constituents, and barometric pressure…but the transfer reference temperature will remain the same. In addition, the unit will transfer “out” of a Mode at a lower reference temperature to prevent the unit from cycling in and out of Modes at a specified load.
Below are the DLN 2.6 transfer temperatures from Mode 1 to Mode 6Q. You can find this reference temperature displayed on the DLN page of the MKV. These temperatures may be slightly different than listed below as they can be modified as part of the tuning process. Prospective Shift Leads should take note of actual transfer temperatures and commit these to memory.
The importance of knowing these transfer points is for Air Permit start-up emissions levels in relation to dispatched load points (we want to get to Mode 6Q as quickly and safely as possible). There are certain loads at which we don’t want to reside for any period of time due to high Nox and/or CO levels, thereby resulting in a Permit violation. You can also reference the GE Emissions vs. Load chart found in the O&M manuals.
- Mode 1 transfer into Mode 3: initiates at 1615 F, completed at 1650 F
- Mode 3 transfer back to Mode 1: initiates at 1590 F
- Mode 3 transfer into Mode 4: initiates at 2000 F, completed at 2050 F
- Mode 4 transfer back to Mode 3: initiates at 1990 F
- Mode 4 transfer to Mode 5 transient: initiates at 2190 F
- Mode 5 to Mode 6Q: initiates at 2220 F, completed at 2250 F
- Baseload TTRF is approximately 2425 F
- Mode 6Q transfer back to Mode 4: initiates at 2170 F
View revised transfer temperatures according to the Mark V studio in this pdf file.