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I have a very interesting experience to share with all here. Last month we had a small short circuit at our interposing panel which cause the Mark V to unload and shutdown the GT. However the short circuit has also caused the 125Vdc supply for 52G operation to trip.
When this happened, 52G remained closed even after the GT when to shutdown mode. When the guys ring me up on the matter (i was about to have my dinner tho.. ), I asked them to check out the breaker position and once they normalize the breaker, 52G opened.
Due to this, the generator was on sync motoring for about 10 minutes. Although there were some bad burnt smell throughout the switchgear room, our inspection shows everything is in good condition (god bless those ABB SACE switchgear engineers ). I also monitored the generator winding temperature throughout the motoring period and there were no significant changes. The vibration level were also normal.
Throughout the motoring period, the speed and terminal voltage remained the same although the load has gone down to zero. We started back the unit and there were no problem.
What I'm still wondering is that from what I have read on books and articles before, motoring of the generator would cause some serious damage but in my case everything is 'seem' to be normal.
Any one have experienced similar situation before hope can share here.
Lastly I had one question by my guys that when the generator is motoring, should it be on the opposite rotation? I'm very sure that as long as the generator is sycnh to the grid, the phase sequence would be the same and hence the rotation should remain the same. Isn't it?
When this happened, 52G remained closed even after the GT when to shutdown mode. When the guys ring me up on the matter (i was about to have my dinner tho.. ), I asked them to check out the breaker position and once they normalize the breaker, 52G opened.
Due to this, the generator was on sync motoring for about 10 minutes. Although there were some bad burnt smell throughout the switchgear room, our inspection shows everything is in good condition (god bless those ABB SACE switchgear engineers ). I also monitored the generator winding temperature throughout the motoring period and there were no significant changes. The vibration level were also normal.
Throughout the motoring period, the speed and terminal voltage remained the same although the load has gone down to zero. We started back the unit and there were no problem.
What I'm still wondering is that from what I have read on books and articles before, motoring of the generator would cause some serious damage but in my case everything is 'seem' to be normal.
Any one have experienced similar situation before hope can share here.
Lastly I had one question by my guys that when the generator is motoring, should it be on the opposite rotation? I'm very sure that as long as the generator is sycnh to the grid, the phase sequence would be the same and hence the rotation should remain the same. Isn't it?