1 / 18

Shipboard Electrical Distribution

Shipboard Electrical Distribution. …“Shifting the Electric Plant to a Normal Full Power Lineup.”. Topics. Primary Power Electrical Distribution System Components of systems Selective tripping Other AC power generation systems DC Power generation Safety Considerations.

kato-sweeney
Download Presentation

Shipboard Electrical Distribution

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Shipboard Electrical Distribution …“Shifting the Electric Plant to a Normal Full Power Lineup.”

  2. Topics • Primary Power • Electrical Distribution System • Components of systems • Selective tripping • Other AC power generation systems • DC Power generation • Safety Considerations

  3. Primary Power Characteristics • US Residential • 115 VAC Power • 1 phase, 60 Hz frequency • Grounded system • US Navy • 450 VAC Power • 3 phase, 60 Hz frequency • Ungrounded system

  4. Primary Power Characteristics • Why AC? • More power than DC for same size • Why 3 Phase? • More power than single phase • Can operate with only 2 phases - redundancy • Why ungrounded? • NOT Safety • Reliability: at least two faults are required to cause system failure (grounded systems fail with one fault)

  5. Basic Components • Ship Service Generators • Primary source of power is rotating-field generator • Powered by prime mover • SSTG (steam) • GTGS (gas) • EDG (diesel) • Switchboard • Metal enclosure that serves as distribution center (contains buswork, breakers, instruments, etc)

  6. Basic Components • Bus Transfers • Allow transfer of load from one bus to another (normal -> alternate) • ABT: senses voltage loss quickly and auto transfers supply to alternate source to ensure continuity of power • MBT: manual transfer, used for non-vital loads • Disconnects • Used for infrequent connections (shore power)

  7. Basic Components • Circuit Breaker • Used as switches to connect buswork • Trip open and break circuit if unsafe condition (over current, under voltage, under frequency) • Arc Fault System • Fuse • Simplest protective device • Fusible strip of wire melts to provide protection • Must be replaced once blown

  8. Electrical Distribution • Ship Service Distribution System • Provides normal and alternate power • Power from generators switchboards sent to loads, power panels, etc. • Parallel requirements for closing circuit breakers • Emergency Power Distribution • Normally supplied by DG’s • Designed to provide power to vital systems during a casualty

  9. The “Electric Plant”

  10. Electrical Distribution • Casualty Power Distribution system • Use of portable cables for temporary routing of power in severe casualty • Selective Tripping • Principle under which faults are isolated as close to the fault as possible and furthest from power supply • Done via fuses, switches, and breakers (most current system is arc-fault) • Vital vs. Non-vital loads

  11. Other AC Generation Systems • 115 VAC, single phase, 60 Hz used for smaller loads • Used for lighting, outlets, etc. • Step-down transformer • 400 Hz Power • Most of electronics including fire control & sonar use 400 Hz • 400 Hz MG used to convert 60Hz to 400 Hz

  12. DC Generation Systems • Battery: chemical potential due to dissimilar metals (Pb vs. PbO2) in presence of electron bridge (electrolyte) • SSMG: converts AC <-> DC (large machine with an AC end & DC end) • Static Inverters: solid state to replace SSMG’s • Rectifier: converts AC -> DC

  13. Degaussing • Circulation of DC current around the hull to reduce the magnetic signature. • Degaussing stations • Magnetic exploders

  14. Safety Considerations • #1 On-the-job KILLER of sailors • Working in vicinity of energized gear requires CO’s permission • NUMEROUS electrical safety precautions • Electrical Tagout to de-energize where possible • Rubber gloves • Insulated tools • Diamond deck • CPR qualified personnel • Removal of jewelry/metal objects • Etc.

  15. Any Questions?

More Related