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Hi All,
there is a frame-V gas turbine which runs in natural gas. This machine had a smooth performance history till date. recently, we have upgraded its control system from mark-v to mark-VIe. After up-gradation during commissioning tests it was ok. after loading, around 3/4 days later it was observed that hydraulic oil pressure is getting a jerk from 85kg/cm2 to 97kg/cm2 (~for 0.5 sec in every 10sec). The pressure surge was present only during MHOP, when AHOP was running before FSNl no hunting observed.
In addition to it, IGV LVDT feedback trouble alarm was also appearing.
To solve the MHOP pressure surge issue, we take down the machine to FSNL then, checked the release valves of AHOP & MHOP line (interchanged the valves MHOP & AHOP for sure), checked almost every part mechanically but no improvement.
So being failed to solve the MHOP pressure hunting by mechanical checks, we started machine again.
Again after 7 days, machine put shut down and LVDT of IGV was replaced. After that, when we started the machine the MHOP pressure hunting just vanished like a magic.
My question is What may be the reason
1. for MHOP pressure hunting?
2. How it vanished after only rectified the IGV LVDT?
there is a frame-V gas turbine which runs in natural gas. This machine had a smooth performance history till date. recently, we have upgraded its control system from mark-v to mark-VIe. After up-gradation during commissioning tests it was ok. after loading, around 3/4 days later it was observed that hydraulic oil pressure is getting a jerk from 85kg/cm2 to 97kg/cm2 (~for 0.5 sec in every 10sec). The pressure surge was present only during MHOP, when AHOP was running before FSNl no hunting observed.
In addition to it, IGV LVDT feedback trouble alarm was also appearing.
To solve the MHOP pressure surge issue, we take down the machine to FSNL then, checked the release valves of AHOP & MHOP line (interchanged the valves MHOP & AHOP for sure), checked almost every part mechanically but no improvement.
So being failed to solve the MHOP pressure hunting by mechanical checks, we started machine again.
Again after 7 days, machine put shut down and LVDT of IGV was replaced. After that, when we started the machine the MHOP pressure hunting just vanished like a magic.
My question is What may be the reason
1. for MHOP pressure hunting?
2. How it vanished after only rectified the IGV LVDT?