Shipboard Electrical Distribution - PowerPoint PPT Presentation

1 / 18
About This Presentation
Title:

Shipboard Electrical Distribution

Description:

Provides normal and alternate power ... Designed to provide power to vital systems during a casualty. The 'Electric Plant' ... Casualty Power Distribution system ... – PowerPoint PPT presentation

Number of Views:2352
Avg rating:3.0/5.0
Slides: 19
Provided by: LTChad
Category:

less

Transcript and Presenter's Notes

Title: Shipboard Electrical Distribution


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 -gt 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 DGs
  • 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 lt-gt DC (large machine with an
    AC end DC end)
  • Static Inverters solid state to replace SSMGs
  • Rectifier converts AC -gt 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
    COs 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
(No Transcript)
16
(No Transcript)
17
(No Transcript)
18
Any Questions?
Write a Comment
User Comments (0)
About PowerShow.com