Generators running in partalle on board a ship

 

Very well, actually.

Your question is very vague. Generators aboard ships are run in parallel just like they are on shore. The difference may be that on board ships there is likely some kind of automated control method for controlling frequency and sharing load and monitoring and sharing reactive load (VArs)--something often called a PMS: Power Management System.

But, the act of paralleling--synchronizing--AC (Alternating Current) generators (more correctly called alternators) is the same as it is everywhere else on Planet Earth. It's just that possibly on some newer vessels frequency control and load sharing (real and reactive loads--MW and MVArs) may be done with an "extra" control system sending commands to the various generator sets to automate what can be done by humans.

If you have more specific questions, we will try to answer them.

(Most prime mover governors (diesel engine- and/or turbine control systems) are operated in Droop Speed Control mode, whether aboard ships or on shore. There are some forms of Isochronous load-sharing for smaller generation, transmission and distribution systems (which does also describe an electrical power system on a ship as well as on land!), and some other schemes--but, in one form or another, they are all some version of Droop Speed Control which allows multiple generators and their prime movers to act as one large generator and prime mover to power a load, usually made up of many smaller loads. Droop Speed Control allows the various machine which are paralleled--synchronized--together to stably and smoothly share in the production of power to power a larger load than any single generator might be able to power individually.)

So, that's my best attempt at answering your vague and unspecific questions, @Beyan Dukuly.

 

Lots of posts on here, many from @WTF? , about droop speed control. Pay close attention to ones that cover island operation because that's what you have.

I worked on a diesel-electric workboat (offshore oil industry) for a number of years. It was built in the early 1980s and the generator controls were analog electronics. Each of the 4 gensets had a control module and they were connected together in a daisy-chain configuration so that the lowest-numbered generator that was online was the master and the others the slaves. The master's frequency setting would set the frequency of the system. However, if a higher-numbered genset was online and had a higher frequency setting, there would be instability. When adding a higher-numbered generator, we would have its frequency setting slightly higher than the bus (as usual) and then turn it back down a little once its breaker was closed. Taking the lowest-numbered generator offline was also a process where we would have to make sure that the remaining generators were properly set.

That system handled load sharing automatically. We had very little control over how the real load was managed. We could tweak the VARs a little by adjusting the voltage regulator but we never messed with it in real life. The system was well designed and "just worked".

All that to say, that the PMS was old, primitive, and very effective as long as we took basic precautions. If your ship is newer, its PMS will likely be more sophisticated and my answer will be less useful to you.