Does 63EA alarm activation actuates opening of gas turbine bypass damper in GE frame 6 mark vi ?

A

Thread Starter

ARM

I wanted to know that in GE Frame 6 machine Mark VI logic- will exhaust pressure high alarm 63EA will lead to opening of bypass duct damper in combined cycle?

what is the logic of exhaust pressure high for damper cycle in frame 6 GE machines?
 
ARM,

Since GE doesn't typically supply HRSGs and dampers (but it might) it's not typical for them to use any turbine input devices to control dampers in the turbine exhaust.

Another control.com contributor, otised, might have some other experiences since he worked in the Projects department.

You would need to look at the application code running in the Mark VI and see if it somehow communicates a high exhaust back-pressure alarm (from 63EA) to the DCS (which is where the damper control is usually implemented) and then if the DCS takes some action based on that information. The "communication" between the Mark VI and the DCS (which might also be a Mark VI if GE or one of it's packagers provided the balance of plant control system, the DCS) might be a relay output (contact closure) or if it's Mark VI-to-Mark VI communication it might be over the EGD so it would be a software communication.

We just don't know enough about the configuration of your site. But, again, control of elements in the exhaust downstream of the gas turbine is not typically done by or using the gas turbine control system I/O so it's not possible to say with any degree of certainty what was done at your site without actually being able to see the .m6b file from the Mark VI at your site, and possible the sequencing or application code in the DCS at your site (which is where the damper control is usually implemented).

Hope this helps!
 
GE would typically open the bypass damper on the 63EA high exhaust pressure alarm. The logic for that would likely be in the HRSG controller rather than the gas turbine control. It has been a long time (over 20 years) since I worked on any unit with a bypass damper, but back then we always put the damper control in the HRSG controller, with some hardwired protective interlocks wired direct to the gas turbine control.

Also, if you have any supplemental firing of the HRSG, that would also be shut off any time the bypass damper opened.
 
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