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

13. 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.

17. 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