GE frame 6b the IGV actual closed 34 Deg but feed back 64.9 Deg. we replaced the servo and hydraulic filter and down load I/O Confg. the calibration to verified opening and feed back matched more than 64.9 Deg not open at 57 Deg.

any help and guide to adjusted the LVDT very difficult to reach in very closed placed.

 

Dear Samtronic,

Looks like the io_cfg values are not calculated and fed to the configurator.

Please recalibrate, check zero and Max opening angle voltages during the next shutdown from the LVDT's and calculate zero and 100% as per the equation in the manual. and feed them in IO_Cfg

Approach to LVDT is difficult but a coordination with Mechanical persons is required to open up manhole and IGV cover plate at Bellmouth compartment.

All the best
Mambo

 

Dear Mambo

we start the Turbine by force L3IGVF2 force to <0> and L86GVT force to <0>. the IGV angle still closed 34 DEG until loaded 10 MW then open to 68DEG. I get the 96TV-1 feedback 0.396 V RMS and 96TV-2 feed back 0.67 V RMS when the IGV 34 DEG. I think 96TV-2 this make a problem to high value select CSGV_B. I remove the input 7 V RMS to check. all thing now normal so we need to adjusted the 96TV-2 but we cannot. the place its very closed required remove many support to reach the LVDT no any procedure to do that.

 

Dear Samtronic,

Never start turbine with logic forced signals until one is expert in what he is doing. This is a serious problem that IGV opens only after 10 MW loading. What about the exhaust temperatures, I think they are well above the normal at this load.

OR, IGV's are opening but values calculated are wrong.
Normally for a frame 6 turbine around 86% turbine speed the IGV starts opening to 57 DGA.

Please shutdown the machine and check mechanical travel of IGV's, 34 DGA is close angle and 84 DGA is open angle sometin=mes 86 DGA is also considered full open angle.(Mechanical stop close is around 28 DGA and Mech Open stop is around 90 DGA)

Check both LVDT's and set the correct volts, open and close angles and set them after calculation to IO Configurator.

All settings to be done by a qualified person with knowledge on turbines( Controls Engineer), many previous discussion are found for IGV Controls and calibration if you search for the topic on control.com

All the Best
Mambo

 

Dear Mambo

thanks for guide. we start the unit by force and remove the force at FSNL. this is as urgent start. the unit after remove the force every thing normal IGV DEG 65 loading the unit normal. but when stop, the machine take trip not complete normal shutdown. we under stand the problem. I do some temporary remedy till time inspection. I remove the LVDT. it has a higher feed back and now working normal by one LVDT so no need to force any more.

best regards
Sam