Electrical Systems

1
Electrical Systems

• Electrical Engineering in Railways
• Rolling Stock
• Communications Control
• Signalling
• LV Installations in Stations and Buildings
• Electrical Systems

2
Electrical Systems

3
Electrical Systems

• High Voltage Aerial Lines and Underground Cables
• Substations
• 1500V dc Traction System
• Overhead Wiring
• Traction Return
• Power Supply for signalling operation,
  communication equipment, station and buildings,
  etc
• LV installations in Railway Tunnels and Yards

4
Electrical Systems

• Statutory Environment
• Rail Safety Act 2002
• Electricity Supply Act 1995
• Electricity Supply (Safety Network Management)
  Regulation 2002
• RailCorp is one of the Electricity Distributors
  in NSW

5
High Voltage A.C. Distribution System

• Standard Voltages
• 11kV
• 33kV
• 66kV
• 132kV
• Modes of transfer
• Overhead Transmission Lines
• Underground Cable

6
HV Aerial Lines

• Conductors
• Copper
• Aluminium (AAC or Aluminium Alloy)
• Conductor Supports
• Wood Poles
• Steel Poles

7
HV Cables

• Conductors
• Copper
• Construction
• Paper insulated lead sheathed
• XLPE
• Configuration
• Underground
• Galvanised Steel Troughing / Ground Line
  Troughing

8
1500V D.C. System

• Electric Trains in NSW Run on 1500V D.C.
• Power is supplied from traction substations to
  trains by means of the overhead wiring (OHW)
  system
• Trains collect current through pantographs
  sliding under the contact wire
• Current returns to the substations via traction
  rails

9
Traction Substations

• Switchgear
• AC Circuit Breaker
• DC Circuit Breaker
• Transformers Rectifiers
• Convert the high voltage ac supply to 1500V dc
• Control and Monitoring
• SCADA (Supervisory Control and Data Acquisition)

10
Traction Substations

• Substation Spacing
• Typically 4km to 15km
• Depends on a number of factors including
• Train loads
• Track grades
• Losses
• OHW types
• Train headways
• Electrolysis

11
Overhead Wiring (OHW)

• Overhead Wiring Systems in RailCorp
• Simple Catenary
• One or two contact wires supported by a catenary
  wire
• Compound Catenary
• A main catenary supports an auxiliary catenary,
  which in turn supports the contact wire
• Contact Only

12
Overhead Wiring

• Tensioning Modes
• Fixed Anchored
• Wires rigidly anchored at both ends of the wire
  run
• Tension in the wire varies with temperature
• Wire sags down at high temperatures
• Regulated Tension
• Tension is the wire is held approximately constant

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Overhead Wiring (OHW)
14
Overhead Wiring (OHW)
15
Overhead Wiring
16
Power Supplies

• Supplied from High Voltage Distribution System
• Generally from the 11kV Network
• Transform voltage to 415V or 240V
• Signalling Supplies
• Generally two independent source of supplies are
  provided
• Normal supply from RailCorp HV Distribution
  System
• Standby supply from local electricity
  distributor
• Power supplies to stations, buildings, workshops
  and other LV installations.

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Electrical Systems

• Challenges
• Reliability
• On Time Running
• Single Contingency (Except for OHW)
• Double or Triple Contingency at Critical
  Locations
• Design to minimise restoration time after
  failures
• Safety
• Statutory Clearances
• Permit System
• Safety in Design