The document discusses the Supervisory Control and Data Acquisition (SCADA) system used by Indian Railways to control electric traction supply. Some key points: - SCADA allows centralized control of circuit breakers and switching stations along tracks from remote control centers. It also acquires field data. - The system includes remote terminal units (RTUs) in the field, communication networks, and a central control room with workstations and servers. - It monitors and controls over 17,000 km of electrified tracks through around 53 remote control centers. - SCADA uses protocols like IEC-870-5 for communication between the control center and RTUs to ensure interoperability between vendors.

1. 1
Supervisory control & Data Acquisition
(SCADA) systems on I.R.
• Indian Railways is having SCADA system for
controlling 25 kV electric traction supply since 1976.
• SCADA is meant for controlling switching ON / OFF of
circuit breakers, interrupters at unmanned traction
substations (TSSs) and switching stations located along
the track.
• SCADA is also used for data acquisition from field.
• Control is exercised through a centrally located Remote
Control Center (RCC).
• I.R. controls 25 kV Traction Supply of 17000 kms of
electrified territory through approx 53 Remote Control
Centers

2. 2
Modem Modem
Main
Communication
Processor
Hot Standby
Communication
Processor
1a
10/100 MBPS TCP/IP LAN
Modem
Modem
1b
Main SCADA
Server with
HDS
Hot Standby
SCADA Server
with HDS
Operator Workstation
2a 2b
Operator Workstation
DOT/OFC Cable
Controlled Post
PANKI
SSP
KANPUR ( W )
SP
SIRATHU
FP
KUNWAR
SP
KHAGA
SSP
RASULABAD
TSS
FAIZULLAHPUR
SP
FATEHPUR
SSP
MALWAN
FP
BINDKI ROAD
SP
KARBIGWAN
SSP
SARSAUL
TSS
CHAKERI
SSP
KANPUR ( E )
SP
SUJATPUR
SSP
BHARWARI
SP
SAIYAD
SSP
MANAURI
TSS
BAMRAULI
SP
ALLAHABAD
SSP
NAINI
FP
JEONATHPUR
SSP
JEONATHPUR
TSS
AHRAURA
SP
CHUNAR
FP
PAHARA
SP
MIRZAPUR
TSS
BIROHE
SP
JIGNA
FP
UNCHDIH
SP
BHEERPUR
TSS
KARCHNA
SP
WAN 1 (MGS -ALD )
WAN 2 (ALD -PNK )
SCADA Equipment

3. 3
Block Diagram of SCADA
Man Machine Interactive (PC)
Host computer (PC)
Front End Processor(PC)
RCC
modem
modem
R
T
U
modem
R
T
U
modem
R
T
U
modem
R
T
U
modem
R
T
U
modem
R
T
U

4. 4
Modern SCADA equipments e.g.
RTU, MODEM & CPU

5. 5
SCADA SYSTEM COMPRISES OF
THE FOLLOWING
• REMOTE CONTROL CENTRE
(RCC)
• REMOTE TERMINAL UNIT (RTU)
• COMMUNICATION MEDIUM

6. 6
FRONT END PROCESSOR
• Two Front End Processors One Main and
Other Standby( One Hot Standby )
• IF Both FEP Fails than one of MMI can be
made as FEP.(Cold Standby)
• Coded information from field are first
received by the Modem and then Modem
after digitizing gives it to FEP .
• FEP software validates and receives valid
data only other are rejected.

7. 7
Host computer
• Host computer is main SCADA Computer
having overall control on all other
computers.
• There are Two Host computers one is main
and other is Hot Standby.
• Addition deletion of RTUs and other
configuration application is carried out from
Host Computer.

8. 8
Host computer(Contd.)
• Host computer processes and decode the
information received and sends it to MMI
for Display.
• Similarly the command issued by operator
from MMI first received by Host and
generates data packets and send these
packets to FEP for further transmission on
Line

9. 9
MAN MACHINE INTERFACE
MMI
• MMI Displays the Single Line Diagram of
Traction Power supply.
• The Information received from Host is
displayed at relevant place on Mimic
diagram.
• Operator issues Telecommand on MMI
which is processed through Host & FEP as
explained.

10. 10
MMI(Contd.)
• Man Machine Interface(MMI) provides basis
for all interactions between operator and
SCADA system
• A full graphics MMI presents the monitored
parameters in an easy to understand
graphical display.
• It also provides features to attract attention of
operator visually on occurrence of alarms.

11. 11
MMI (Contd.)
• System also provides three security levels for
access to different operations.
• a) Traction Power Controller level:- access to
view and control.
• b) RCC Engineer:- Access to edit
configuration, add user(TPC) in addition to
above.
• c) Higher level:-Facility to add RCC
engineer and manage user permission in
addition to above two.
• All actions are menu driven and prompting
such that errors are minimum.

12. 12
Flow diagram 1
M
RTU
Modem
FEP
PC
• Command Flow diagram RCC To RTU
HOST
PC
MMI
PC
Operator
Analog signal digital signal

13. 13
Flow diagram 2
• Command Flow diagram RTU To RCC
HOST
PC
Operator
M
FEP
PC
MMI
PC
RTU
M
Analog signal digital signal

14. 14
SOFTWARE FEATURES
(Telecommands)
• Execution of telecommands
• Time synchronisation of RTU and RCC
• Test procedure to check communication health
• “OFF” Scanning of RTUs to isolate defective
RTUs.
• Downloading of parameters from RCC to RTU
• Diagnostic of RTU’s from RCC upto card level

15. 15
• Interlocking of devices to avoid undesirable
operations.
• Locked out signals for various devices.
• Printing of data & Reports
• Monitoring of Power block like alarms and
their logging.
• Audible Alarm.
SOFTWARE FEATURES
(configuration)

16. 16
SOFTWARE FEATURES
(configuration)
• Maximum Demand(MD) monitoring.
• Under voltage range setting at SP’ RTUs for
tripping under extended feel conditions.
• Auto Fault Localisation .-software prompts
TPC to start AFL
• Picture editor- To add/delete device etc.

17. 17
REMOTE TERMINAL UNIT
• RTU is common interface between Field
devices and RCC
• RTU is Microprocessor based logic system.
• Accepts digital and analog input signals
from field
• Receives control command from RCC.
• Replies information asked by RCC.

18. 18
RTU Architectural Details
• Power Supply Unit
• CPU
• Digital Input Module (DIM)
• Digital Output Module (DOM)
• Analog Input Module (AIM)
• Signal Conditioning Card

19. 19
RTU Architectural Details(Contd.)
• Modem-For Modulation and Demodulation
• Contactors- To extend 110 supply to field
devices for operation.
• Transducers: For Voltage , Current and
Power factor measurement

20. 20
BASIC BLOCK DIAGRAM
OF RTU
• Battery 240 V AC
CPU DIT DOT AIT
Power supply unit
Modem
Trans-
ducers
Tx Rx
C O N T A C T O R
S.C.Card
input from Field devices

21. 21
RTU FUNCTIONAL DETAIL CPU
• CPU: Microprocessor based logic System
coupled with firmware Programming
performs as a brain of RTU
• 16 bit device
• 20 MHz Speed
• Built in RAM/Backup EPROM-128 KB
• Watchdog Timer

22. 22
Digital Input Module(DIM)
• Digital Input module provide Input point
for Status Information to CPU.
• This provides bistate field devices status to
CPU of RTU.
• Digital Input module accepts input from
field via Signal conditioning card

23. 23
Digital Output Module(DOM)
• Digital Output module receives Output from
CPU.
• The output signal from DOM derives a
interposing relay/Opto-coupler which in
turn extend 110 dc supply to contactor
• The Contactor extend supply to Field
device for operation.
• Each device has separate contactor for each
open and close operation

24. 24
Analog Input Module(AIM)
• Transducers receives analog signals from
CTs /PTs.
• Transducers convert them to proportional
digital values.
• These values are fed to Analog Input
module(AIT) and then to CPU.
• CPU transmits them to RCC as per protocol

25. 25
STATUS &TELESIGNAL FLOW
DIAGRAM
T DIM Mod
em
Mod
em
FEP
Host
MMI
TPC
RCC
CPU
• .
SC card
Field
device
RTU

26. 26
TELEMETRY FLOW DIAGRAM
.
CT/
PT
Transduc
er
AIM CPU Mod
em
Mod
em
FEP
Host
MMI
TPC
Field
RCC
RTU

27. 27
WHAT IS A PROTOCOL ?
• What is a Communication Protocol ?- A
defined rules and regulations for
Communication between two Intelligent
devices. i.e. between RCC and RTU.
• Why a standard Protocol? To ensure
interchangeability of RTU of different
vendors.
• Based on International Standard IEC-870-5
Standard Communication Protocol is based
on IEC-870-5 .

28. 28
Equipment layout of standard system
at RCC

29. 29
29
Maintenance of Remote Control
Centre / RTU
Remote Control Centre
• Monthly Schedule
Dust cleaning
Level checking (RCC & POST)
• Half Yearly Schedule
Dust cleaning
Level checking (RCC & POST)
Voltage / Current checking

30. 30
30
Maintenance of Remote Control
Centre / RTU (Contd.)
Remote Control Centre
• Yearly Schedule
Dust cleaning
Slot & contact cleaning with contact cleaner
Level checking (RCC & POST)
Voltage / Current checking

31. 31
31
Maintenance of Remote Control
Centre / RTU (Contd.)
Remote Terminal Unit
• Half Yearly Schedule
Dust cleaning
Level checking (RCC & POST)
Voltage / Current checking
• Yearly Schedule
Repeat half yearly schedule
Slot & contact cleaning with contact cleaner

32. 32
32
Maintenance of Remote Control
Centre / RTU (Contd.)
Remote Terminal Unit
• Four Yearly Schedule
Dust cleaning
Slot & contact cleaning with contact cleaner
Remove all cards/module clean & refix
Level checking (RCC & POST)
Voltage / Current checking

33. 33
Traction Power Control (TPC)
Organization
RCC
• Heart of Control System
• Manned 365x24
• No operation in system without TPC approval
Traction Power Controller
• Contact with power supply authority
• Liasion with section controller
• Breakdown. Co-ordination & control
• Record Maintenance, Log Books, Shift registers

34. 34
Traction Power Control Organization
(Contd.)
• Isolation of Faulty Section.
• Faulty Section to be kept isolated.
• Advice to Section Controller.
• Information to Traction Staff.
• Action to Rectify Fault.
• Monitoring faults on Railway Equipments,
Grid, Power supply.
34

35. 35
Emergency Arrangement
• T&P Spares in TOWER WAGON/
TRUCK/ART
• Vehicle Truck/TW/Jeep/Wiring train
• Emergency Stores
• Emergency staff
• Emergency telephone
• Role of TPC
35

36. 36
Co-Ordination with Operating
& other departments
OPERATING
 Request for Power Blocks from traffic department.
 Tower wagon movement control.
ENGINEERING
 Power block for P Way maintenance.
 Bonds maintenance
 Maintenance of overhead structures.
36

37. 37
Co-Ordination with Operating &
other departments (Contd.)
S&T
• TPC/ SCADA/ Emergency Telephoning Circuit
operation
• Protection of signal structures (Earthing/Bonding)
• AT supply to CLS panel.
• BT/RC Circuit
37

38. 38
Liaison with Power Supply
Authorities
• Agreement between Railway Authority &
Supply Authority.
• Periodic meeting meetings at different level.
• Reliability of supply & maintenance of
voltage frequency.
• Treated as essential load
• Frequent Power Supply interruption.
• Power line crossing maintenance issues.
38

39. 39
Liaison with Power Supply
Authorities (Contd.)
• Supply failure actions
• Tariff revision issues
• Load revision issues
• Reliability of SEB protection system
• Maximum demand management.
39

40. 40
Safety Precautions for Electric Section
(Contd.)
Rules For S&T Installation
• Effect of OHE on S&T Equipment.
• Precaution in Event of Breakage of wires.
• Working on Signal Post & Fittings.
• Precaution against built up of Potential due
to Return Current in Rails.
• Induction Potential in Metallic.
40

41. 41
Safety Precautions for Electric Section
(Contd.)
Over-Dimensioned Consignment
• Precautions for movement of ODCs.
• Power Block for movement of ODC.
Other Precautions
• Hoarding Boards.
• Rubber Tyred Vehicles on Railway Wagons
• Loading & Unloading of Petroleum Product
41

42. 42
Safety Precautions for Electric Section
(Contd.)
Rules Applicable to P-Way staff.
• Continuity of Track.
• Permanent Way Tools.
• Track-Circuited Rails.
• Care in Handling Pipes etc.
• Steel Measuring Tapes not to be used.
• Traction Structure Foundation.
42

43. 43
Safety Precautions for Electric Section
Watering of carriages
• Watering Section
• Controlling Switches
• Sequence of Interlocking & Operation.
• Authorized to open Interrupters & Isolators.
• Custody of Keys, Watering of Carriage.
• Restoration of supply.
43

44. 44
TRACTION STORES & ITS
ACCOUNTAL
Main Central Depot
• Sub Depot Store (OHE & PSI Depots)
• Emergency Store
• Store at Tower Wagon/Tuck
• T&P/Spares/Consumable
• Ledgers maintained at sub depots

45. 45
TRACTION STORES & ITS
ACCOUNTAL
• Standardization of stores
• Stock item & NS items
• Stocking on basis of AAC
• Stock items directly by stores department
• Special requisitions.
• Liasion with stores department

46. 46
TRACTION STORES & ITS
ACCOUNTAL
• Non stock procurements on basis of demand
• Preparation of indents
• Requisition to stores
• Local purchase
• PAC & Imported items

47. 47
TRACTION STORS & ITS
ACCOUNTAL
• Custody & accountal
• Inspection of stores
• Inventories of dead stock
• Accountal & disposal of scrap etc.
• Condemnation & verification of stock
• Stores computerization

48. 48
Regulation for Electrical Crossing of
Railway tracks.
General
• Approval of Works by Railway.
• Compliance with Indian Electricity Act
• Compliance with Indian Standard Spec.
• Protection of Communication Line.
• Maintenance of Crossing, Defects & Failure.
48

49. 49
Regulation for Electrical Crossing of Railway
tracks. (Contd.)
49
Item Remarks
Angle of Crossing  At right angle to the railway track.
 In special cases, a deviation of upto 30°.
 Deviations < 30° – Authorized by EIG/CEE.
Crossing span  Crossing span – 300 m or to 80% of the normal span,
whichever is less.
Wind pressure  Maxm wind pressure – As prescribed in IS:802 (Part-1)-
1977 for load and permissible stresses.
Temperature  Maxm & Minm temperatures for design of conductors &
other wires – As prescribed in IS:802 (Part-1, Clause-4)

50. 50
Regulation for Electrical Crossing of
Railway tracks. (Contd.)
Overhead Line Crossings
• Minimum clearances between crossing
conductors & any Railway structure.
• Minimum vertical clearance between power
line crossing.
• Clearance bet. Power & communication line.
• Insulators & Guarding.
50

51. 51
Regulation for Electrical Crossing of
Railway tracks. (Contd.)
Overhead Line Crossings
• Anti-Climbing device & warning notice.
• Protection from moving road vehicles.
• Communication line.
• Earthing.
• Fire Hazards.
51