We had an event today onboard our ship. Two of our thrusters were running, and only one diesel generator. This is possible during calm weather, but with a bit of wind, it can not be done, because the thrusters have to work more to keep the ship in position.
So the wind increased and the navigators decided to start a second generator. But the stand-by generator did not connect quite so successfully to the main bus bar. It connected, was connected for about 5 seconds, then got thrown off again, and we got the alarm "DG1 Abnormal MSB open"
First off, I think it took about 2 minutes to synchronize, which usually takes like 30 seconds, at most. Then when the generator got in for those 5 seconds, the "Produced effect" indicator got in reverse, counting from -1 kW and tapping out at -130 kW, 5 sec later.
Now, this generator usually counts reverse at first, but after a few seconds, it goes to 0 kW and then starts to produce power. But we usually connect it while there is low load on the main bus bar, around 500 kW.
This counting in reverse thing, is it because the voltage on the generator is so low, that the main bus bar (higher voltage at this point) starts to actually drive our generator/motor, instead of the generator supplying power? That is the only way for the generator to become a consumer, right?
If the voltage is low, then does it have something to do with the revolutions on the generator? I don't remember if we experienced a major drop of frequency, when generator 1 tried to connect. We probably did.
So the wind increased and the navigators decided to start a second generator. But the stand-by generator did not connect quite so successfully to the main bus bar. It connected, was connected for about 5 seconds, then got thrown off again, and we got the alarm "DG1 Abnormal MSB open"
First off, I think it took about 2 minutes to synchronize, which usually takes like 30 seconds, at most. Then when the generator got in for those 5 seconds, the "Produced effect" indicator got in reverse, counting from -1 kW and tapping out at -130 kW, 5 sec later.
Now, this generator usually counts reverse at first, but after a few seconds, it goes to 0 kW and then starts to produce power. But we usually connect it while there is low load on the main bus bar, around 500 kW.
This counting in reverse thing, is it because the voltage on the generator is so low, that the main bus bar (higher voltage at this point) starts to actually drive our generator/motor, instead of the generator supplying power? That is the only way for the generator to become a consumer, right?
If the voltage is low, then does it have something to do with the revolutions on the generator? I don't remember if we experienced a major drop of frequency, when generator 1 tried to connect. We probably did.
Attachments
-
108.3 KB Views: 11