Marine electrical systems

[pavement]

Do any of the experts have practical experience of marine power systems, with particular emphasis on protection?, i would love if someone could give me a pointer in the direction to a good website,book to illustrate the difference between utility protection techniques and the islanded system counterparts. I'm finding it hard to find any material relevant courtesy of the web etc, as it seems to be very sparse.

Many Thanks!

 

[RajT]

You can obtain Lloyds shipping regulations which defines electrical power systems on ships.
Note that when it comes to protection, there is no difference between say an electrical system on a ship and a industrial plants.

 

[jbartos]

Suggestion: Visit

http://www.ieee.org

for IEEE Std 45

 

[jbartos]

Suggestion: Visit

http://www.tc.gc.ca/marinesafety/TP/Tp127/construction.htm

http://www.uscg.mil/hq/msc/PRGuidance/e2-21.pdf

etc. for more info

 

[Midos]

Rajt, above is correct not a great deal of difference in electrical protection on ships or on industrial plants onshore if the budget is available $$, However! many FPSO's/ships utilise the "IT earthing system" (high Impedance earthing)This is where the fault level is reduced by a high ohm resistor say! 3810 ohm for a 6.6kv grid would reduce the fault current to 1amp on the HV bus bar. This system design is well used on ships/FPSO's as it would keep the boat sailing etc in bad weather even under a severe fault that would normally shut down essential plant. Cant think of any books that would explain this in great detail as it can take some time to get your head around. The IT earth system is not used much on onshore plants, however it is used in the UK a good deal to supply remote farms etc by overhead lines. The Llodys book on ship class does cover a bit but not enough to warrent the high £££ to buy it.

 

[advidana]

Try searching the US navy or maritime manuals for design of ship board electrical systems. Check United States Federal Documents web site.

 

[pavement]

Thats also another issue, because this vessel uses Ddo Tx's, which is complicated by the fact that this configuration is never covered is never covered by texts etc, though schemes such as BEF(balanced earth faults) are covered, which i'm assuming both sides will be protected by, does any experts who have practical experience could give me other schemes to be aware of, if possible.

Thanking yous.

 

[RajT]

Pavement,

You don't have to specify Ddo Txs as it is not a must.
You can design a marine distribution just like an industrial plant ie specifying Dyn11 arrangement if thats what you are uesd to or understand better.
Also on some application (ships/FPSO/Offshore platform) an unearthed system is specified (albeit only on the LV system) but its' merely out of choice noting that modern practice is to specify solidly earthed LV system which is familier to more engineers.