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Dear Friends,
We have a Hitachi H-25 (25 MW) gas turbine. recently due to tripping of one of our auxiliary transformers, our supply to Gas turbine auxiliary MCC had tripped. GT MCC has all gas turbine drives including MOP and MHOP (hyd. pump). we have no shaft attached auxiliary drives.
Normally whenever Mains supply fails in GT MCC, Emergency power comes up within 2 seconds and machine does not trip due to accumulator present in hydraulic line (which does not allow Hyd oil pressure to go low below tripping point). But this time when our GT MCC AC supply failed, local HMI UPS did not give back up. thus local HMI PC failed. also another phenomena happened was that during this whole process control shifted from remote HMI to local HMI, which now was in OFF condition, and all drives came in manual mode.
I am assuming that as all my drives were in manual none of them started again when power was restored and machine tripped on low Hyd pressure.
Unfortunately due to loss of local HMI supply all trends vanished after AC supply failure of GT MCC so i am having trouble for exact diagnosis.
Can anyone help me know is there any reason that my control shifted from Remote HMI to local? and why did all drives come in manual mode?
does AC supply failure to TCP have any effect on it?
Thanks
Manoj
We have a Hitachi H-25 (25 MW) gas turbine. recently due to tripping of one of our auxiliary transformers, our supply to Gas turbine auxiliary MCC had tripped. GT MCC has all gas turbine drives including MOP and MHOP (hyd. pump). we have no shaft attached auxiliary drives.
Normally whenever Mains supply fails in GT MCC, Emergency power comes up within 2 seconds and machine does not trip due to accumulator present in hydraulic line (which does not allow Hyd oil pressure to go low below tripping point). But this time when our GT MCC AC supply failed, local HMI UPS did not give back up. thus local HMI PC failed. also another phenomena happened was that during this whole process control shifted from remote HMI to local HMI, which now was in OFF condition, and all drives came in manual mode.
I am assuming that as all my drives were in manual none of them started again when power was restored and machine tripped on low Hyd pressure.
Unfortunately due to loss of local HMI supply all trends vanished after AC supply failure of GT MCC so i am having trouble for exact diagnosis.
Can anyone help me know is there any reason that my control shifted from Remote HMI to local? and why did all drives come in manual mode?
does AC supply failure to TCP have any effect on it?
Thanks
Manoj