VRIOGS 010.4 RevA - Public Transport Victoria

VRIOGS 010.4 Revision A 7SECTION 4.0INTRODUCTIONA single rectifier unit Substation typically consists of equipment listed below:A 3 phase 22kV AC feeder is run from the 22kV isolator/switch (mounted on a poleoutside the Substation) in conduit to the AC busbar.The AC busbar distributes the AC supplies to one 2MW rectifier transformer, oneauxiliary supply transformer and one signal supply transformer located in thesubstation.The rectifier transformer steps-down the 22kV supply to approximately 581V ACwhich is passed to the rectifier stack where it is rectified to a nominal 1500V DC. Thepositive side of the rectifier is connected to the overhead wire catenary via a DCbusbar, DC circuit breakers and line isolators. The negative return from the runningrails is provided through the wall mounted negative busbar back to the rectifier.The auxiliary transformer supplies power at 415V, 3 phase to the 415/240Vswitchboard which then supplies the local auxiliary services which include batterycharging, lighting control and protection equipment.The substation is generally remotely operated by the Supervisory Control and DataAcquisition (SCADA) System. Local operation of all equipment is also available.An earthing grid is installed beneath the substation building and transformer yard.The DC traction circuit has no direct connection with earth. Stray return currents canbe controlled by the use of Electrolysis Mitigation Equipment which is designed tokeep electrolytic corrosion to a minimum. This will be fitted by others if required, afterthe location has been commissioned and placed into service. Tie stations andSubstations have similar layouts, but not necessarily all the equipment mentionedabove.NOTE: This document is controlled only when viewed on the DOT Engineering Standards website.Any other copy of this document is uncontrolled, and the content may not be current.