dear sir,

We have 2 ge 7ea machines. both are completed hgpi but for one unit the MW output is lesser than the other unit. the diff is 4 MW normally 75 mw but now 74 mw.

so it was happend after hgpi we verified with ge observed cpd is less 0.4 than the actual value. and also verified pasiing of ibh and bleed valve and all other sources but everything found ok. igv showing 84 deg baseload so ge taken shutdown repalced lvdt and calibrated started back the unit but still at base load output is less and cpd also less value. so please give me the suggestions to rectify the problem

 

This question is not easily can be answered. But whenever a machine is producing less output after an inspection, its always ( and I mean always) the c&i guys that will get the blame. There are so many factors that can cause the reduction in output for example the state of the hot gas parts that were changed (is it new or refurbished). If it is refurbished, how many times it was refurbished before and so much is the reduction in the surface area and dimension. Was there an offline water wash done after the inspection? Some times some valves (esp in the atomizing air 20AA) never closed properly could also cause reduction in output.

As for you, my advice would be did you calibrate your cpd transducers, p2 tranducers,gcv or even the 96GG transducer during the inspection? If all that were done and indeed everything in good working order (nobody messed with the control constants), then it might not be a c&i issue at all.

 

Dear sir
during HGPI we replaced first stage nozzles and bucket as per ge and also replaced second stage honeycomb shroud because of erossion. we calibrated compressor discharge pressure transducers, igv calibration, ibh control valve inspection, p2 pressure transmitters calibration and all gcv and srv calibrations bleed valves replacement with new one. replaced inlet air filters with new one. These all activities are done properly but still we are not able to findout the reason why its not reaching baseload output. verified all wheelspace temperatures found normal.