There are three STG sets operating in parallel mode and fourth is added to the system. we have to operate all the STG sets in parallel only there is no possibility of operating in island mode. All the STG sets are having Woodward Electronic Governor 505 with 4% Droop. In the fourth STG set programme the Use KW Droop is mentioned as NO as the KW transducer is wrongly selected and similarly use KW input it is mentioned as NO.

The result seen after synchronisation is the reference speed and actual speed there is hardly difference of 35 to 45 rpm during 60 % load. The other important phenemenon is that any load changing in the comman bus is effecting the new STg set. Kindly tell me the possibiliites.

 

If the STG is synchronized with Bus, then this behaviour is expected. Refer to earlier posts regarding synchronization.

Are you expecting something else?

Regards,
Tomy Zacharia

 

I think the "problem" is that it seems the Woodward 505 wants to use KWDroop and it has been disabled. Apparently, if KWDroop is disabled then the unit doesn't have any droop control?

That doesn't seem likely, but if I remember correctly the 505 has the ability to switch to Isoch mode on a contact closure (such as from a tie breaker). One wonders if that contact closure is causing the unit to be in Isoch control?

It's been many years (more than a decade) since I worked on a 505. I remember the manual wasn't very good (actually slightly worse than most GE manuals, but only slightly). I would suggest the problem with the load transducer input get corrected and KWDroop be enabled.

But, it does seem like the unit is trying to behave like it's in Isoch speed control instead of droop. Why? is the big question.

 

Sir,

I have a problem with the STG governor control by the Woodward 505 out put signal is swing between 75-100% caused the Woodward 505 alarm "kw limit".
I have observed the steam pressure input not fluctuated. pls. tell me the guideline to check.

Regards,
pichet