Hi All,
We are experiencing a high vibration trip from Brg #2 seismic prob during the combustion mode changeover from lean lean to Premix. So far we have experience couple of trips and the vibration value goes up as high of 27mm/s to 35mm/s and at around 60MW. It does not reach trip limit all the time and during a successful changeover, vibration value goes up about 12mm/s. The Brg #2 is fitted with proximity probs and their values have spikes with slight time lag (around 14sec as per system 1 data and increase in value around 50-100%). Unable to capture the frequency domain of this fast spikes . rest of the turbine bearings seismic probs do not experience in any spikes, but Brg #3 shaft vibration experience in spikes with aforementioned time lag of 14 seconds. (change in value from 30-50%, not sure if the system 1 does have a time sync issue with trends)
I've attached two files of Trip event and successful mode changeover events showing gas valve positions/IGV and flame scanner intensities. Turbine is a peaking unit, approximately 5 starts per week.
Any of the forum member has experienced similar issue in the past? any view would be highly appreciated
Ken
We are experiencing a high vibration trip from Brg #2 seismic prob during the combustion mode changeover from lean lean to Premix. So far we have experience couple of trips and the vibration value goes up as high of 27mm/s to 35mm/s and at around 60MW. It does not reach trip limit all the time and during a successful changeover, vibration value goes up about 12mm/s. The Brg #2 is fitted with proximity probs and their values have spikes with slight time lag (around 14sec as per system 1 data and increase in value around 50-100%). Unable to capture the frequency domain of this fast spikes . rest of the turbine bearings seismic probs do not experience in any spikes, but Brg #3 shaft vibration experience in spikes with aforementioned time lag of 14 seconds. (change in value from 30-50%, not sure if the system 1 does have a time sync issue with trends)
I've attached two files of Trip event and successful mode changeover events showing gas valve positions/IGV and flame scanner intensities. Turbine is a peaking unit, approximately 5 starts per week.
Any of the forum member has experienced similar issue in the past? any view would be highly appreciated
Ken
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