Basics of electric traction system . Covering technologies used and their use in Indian railway. Types of traction systems. Working basics of various types. Historical analysis to some extent.

1. ELECTRIC
TRACTION SYSTEM
SUBMITTED BY-HARMANJEET SINGH
ROLL NO-12264
SUBMITTED TO-Dr O.P RAHI
Dr NAVEEN SHARMA

2. ELECTRIC LOCOMOTIVES
ELECTRIC TRAINS RAPID TRANSIT SYSTEMS

3. CONTENTS
 INTRODUCTION
 TYPES OF TRACTION SYSTEMS
 ELECTRONIC SPEED CONTROL METHOD OF DC MOTOR
 PULSE WIDTH MODULATION
 AC TRACTION SYSTEMS
 MERITS AND DEMERITS OF VARIOUS METHODS
 BRAKING OF TRACTION SYSTEMS
 AUXILLIARY EQUIPMENTS
 RECENT TRENDS IN ELECTRIC TRACTION
 CONCLUSION
 INDIAN RAILWAY AND CAREER OPTIONS IN INDIA AND ABROAD
 REFERENCES

4. INTRODUCTION
ELECTRIC TRACTION IS MEANT FOR LOCOMATION IN
WHICH THE DRIVING (TRACTIVE) FORCE IS
OBTAINED FROM ELECTRIC MOTORS(CALLED AS
TRACTION MOTORS).
FOR TRACTION MOSTLY 3 PHASE INDUCTION MOTOR
AND DC MOTOR IS USED ,BOTH HAVE HIGH INITIAL
TORQUE,PREREQUISITE FOR HIGH SPEED
ACCELERATION.

5. TYPES OF ELECTRIC TRACTION
SYSTEMS
DC TRACTION AC TRACTION MULTI SYSTEM

6. DC TRACTION
DC TRACTION USES DIRECT CURRENT DRAWN FROM EITHER
FROM A CONDUCTOR OR OVERHEAD LINES.
MOST POPULAR LINE VOLTAGES FOR OVERHEAD SUPPLY
SYSTEM-1500V DC AND 3000V DC
600V DC-750V DC VOLT RANGE IS USED FOR THIRD
RAILSYSTEMS (ADDITIONAL RAIL IS PROVIDED FOR SUPLLYING
ELECRTRICITY TO TRAIN AND IS CALLED CONDUCTOR RAIL)

7. DC TRACTION USING SEPEX (ELECTRONIC
CONTROL)

8. DISADVANTAGES-
EXPENSIVE SUBSTATIONS ARE
REQUIRED AT FREQUENT INTERVALS
AND OVERHEAD LINE OR THIRD RAIL
MUST BE RELATIVELY LARGE OR
HEAVY.

9. PULSE WIDTH
MODULATION
 MAIN PRINCIPLE IS TO CONTROL
ELECTRIC POWER BY VARYING
POWER.
 CONDUCTION TIME TO LOAD IS
CONTROLLED.
 THE OUTPUT FROM THE
THYRISTOR VARIES FROM 0 TO
MAXIMUM IN PERIOD T.

10. AC TRACTION
• AC TRACTION UNITS DRAW ALTERNATING CURRENT FROM AN OVERHEAD LINE.
• TYPICAL VOLTAGES USED ARE-
 15 KV, 16.7 HZ
 25 KV, 50 HZ
 25 KV, 60 HZ
• FEWER SUBSTATION REQUIRED AND LIGHTER OVERHEAD CURRENT SUPPLY WIRE
CAN BE USED.
• REDUCED WEIGHT OF SUPPORT STRUCTURE.
• REDUCED CAPITAL COST OF ELECTRIFICATION.

11. AC MOTOR TRACTION

12. MULTI SYSTEMS
• BECAUSE OF VARIETY OF RAILWAY ELECTRIFICATION SYSTEMS, WHICH CAN VARY
WITHIN A COUNTRY TRAINS HAVE TO PASS FROM ONE SYSTEM TO ANOTHER.ONE
WAY TO ACCOMPLISH THIS IS BY CHANGING LOCOMOTIVES AT THE SWITCHING
STATIONS.
• THESE STATIONS HAVE OVERHEAD WIRES THAT CAN BE SWITCHED FROM ONE
VOLTAGE TO ANOTHER AND SO TRAIN ARRIVES WITH ONE LOCOMOTIVE AND
THEN DEPARTS WITH ANOTHER.
• OFTEN THIS IS INCONVINIENT AND TIME CONSUMING .ANOTHER WAY IS TO USE
MULTI SYSTEM LOCOMOTIVES THAT CAN OPERATE UNDER SEVERAL DIFFERENT
VOLTAGES AND CURRENT TYPES.
• IN EUROPE ,IT IS COMMON TO USE FOUR-SYSTEM LOCOMOTIVES(1.5 KV DC,3
K.V DC,15 K.V 16.7 HZ AC,25 KV 50 HZ AC)

13. ADVANTAGES OF AC TRACTION
SYSTEMS
• HIGHER POWER TO WEIGHT RATIO.
• RESULTS IN-
 FASTER ACCELERATION
 HIGHER PRACTICAL LIMIT OF POWER
 HIGHER LIMIT OF SPEED
 HIGHER HAULING CAPABILITY
• NO EXHAUST FUMES OR CARBON EMISSIONS.
• LESS NOISE POLLUTION.
• MAINTAINANCE COST LESS THAN DIESEL AND DC TRACTION.
• NO INITIAL HEATUP TIME REQUIRED CAN BE USED IMMEDIATELY AFTER
STARTING.
• HIGHER STARTING TORQUE ABOUT(1.5 TO 2.5 KM/H/S).

14. ADVANTAGES CONTINUED-
• IT IS POSSIBLE TO USE REGENERATIVE BRAKING ON TRACTION SYSTEM.IT LEADS
TO FOLLOWING ADVANTAGES-
 ABOUT 80 % OF ENERGY TAKEN FROM THE SUPPLY DURING ASCENT IS RETURNED
TO IT DURING DESCENT.AND PRESENTLY IT IS MADE AVAILABLE TO OTHER
VEHICLES ON NETWORK.
• SINCE HEIGHT OF ELECTRIC LOCOMOTIVE IS MUCH LESS THAN COUNTERPARTS
THIS ENEBLES LOCOMOTIVE TO TAKE CURVES AT HIGHER SPEEDS.
• NO WEIGHT OF FUEL NEED TO BE CARRIED LIKE(COAL OR DIESEL LOCOMOTIVE).
• FULLY UNIFORMLY ELECTRIFIED RAILWAY DON’T NEED SWITCHING ,MAKING
OPERATIONS MORE EFFICIENT. SWITZERLAND USES THIS.

15. DISAVANTAGES AC TRACTION
SYSTEMS
• SIGNIFICANT COST OF ELECTRIFICATION.
• INCREASED MAINTAINANCE COST OF LINES.
• OVERHEAD WIRES FURTHER LIMIT CLEARANCE IN TUNNELS.
• UPGRADING NEEDS ADDITIONAL COST ESPECIAALY IN CASE THERE ARE BRIGDES
AND TUNNELS.
• RAILWAY TRACTION NEEDS IMMUNE POWER WITH NO CUTS.

16. SYSTEM OF TRACK
ELECTRIFICATION

17. AUXILLIARY EQUIPMENTS
 CATENARY
 CURRENT COLLECTORS
 CIRCUIT BREAKERS
 ON LOAD TAP CHANGERS
 TRANSFORMER
 RECTIFIERS
 SMOOTHING REACTORS

18. • TYPES OF SYSTEM ELECTRIFICATION
• TROLLEY WIRE OR CONTACT WIRE-SUSPENDED WITH MINIMUM OF SAG SO THAT
CONTACT BETWEEN THE TROLLEY WIRE AND CURRENT COLLECTOR CAN BE
MAINTAINED AT HIGHER SPEEDS.
• THE WIRE IS SUPPORTED BY ANOTHER WIRE CALLED AS CATERNARY.
• TWO DIFFERENT TYPES OF CATERNARY
CONSTRUCTION CAN BE USED-
 SINGLE CATENARY
 COMPOUND CATENARY

20. SINGLE CATENARY CONSTRUCTION

21. CURRENT COLLECTORS
 CURRENT FROM THE OVERHEAD LINE IS COLLECTED WITH THE HELP OF A
COLLECTOR FIXED ON THE ROOF OF THE VEHICLE.
 TYPES OF COLLECTORS-
1. TROLLEY COLLECTOR
2. BOW COLLECTOR
3. PANTOGRAPH COLLECTOR

22. TROLLEY
COLLECTOR
• USED FOR TRAMWAYS AND
TROLLEY BUSES.
• HELD IN CONTACT WITH WIRE
AND SPRING
• SUITABLE FOR LOW SPEEDS 32
KMPH

23. BOW
COLLECTOR
• IT USES A METAL LIGHT STRIP OR
BOUGH FOR CURRENT
COLLECTION ABOUT ONE METRE
LONG.
• NOT SUITABLE FOR RAILWAY
WORK REQUIRING SPEEDS MORE
THAN 120 KMPH.
• REQUIRES REVERSING
ARRANGEMENT OF BOW.

24. PANTOGRAPH
COLLECTOR
• MAIN FUNCTION IS TO MAINTAIN
THE LINK BETWEEN OVERHEAD
CONTACT WIRE WIRE AND THE
POWER CIRCUIT OF THE
LOCOMOTIVE AT VARIOUS SPEEDS
IN DIFFERENT CLIMATE AND WIND
CONDITIONS.
• THIS CAN BE LOWERED OR
RAISED FROM CABIN WITH THE
HELP OF CONTROLLING
CYLINDERS.

25. TRACTION MOTORS
 DC MOTORS-
 DEVELOPS HIGH TORQUE AT LOW SPEEDS AND LOW TORQUE AT HIGH SPEEDS
EXACT REQUIREMENT OF TRACTION SYSTEMS. TORQUE IS INDEPENDENT OF
LINE VOLTAGE THEIRFORE UNAFFECTED BY VOLTAGE FLUCTUATIONS
 SINGLE PHASE AC MOTORS-
 STARTING TORQUE LESS THAN DC MOTOR BUT SIZE AND COST CONSIDERABLY
LESS.MAXIMUM OPERATING VOLTAGE IS 400V.
 THREE PHASE INDUCTION MOTORS-
 PROVIDES CONSTANT SPEED OPERATION,DEVELOPING LOW STARTING TORQUE
DRAWING HIGH STARTING CURRENT AND COMPLICATED CONTROL MAKES IT
UNSUITABLE FOR TRACTION WORKS.
 AUTOMATIC REGENERATION IS THEMAIN ADVANTAGE WITH THIS MOTOR

26. BREAKING OF TRACTION BASED TRAINS
 BREAKING CAN BE ACHIEVED BY TWO METHODS-
1. MECHANICAL BREAKING
2. ELECTRICAL BREAKING
 IN CASE OF ELECTRIC TRACTION SYSTEM ELECTRICAL BREAKING IS USED MAINLY
ALONG WITH MECHANICAL BREAKING.
MECHANICAL BREAKING HAS FOLLOWING DISADVANTAGES-
1. HIGH WEAR AND TEAR
2. NON UNIFORM BREAKING
3. LOSS OF ENERGY
 DUE TO ABOVE SAID DISADVANTAGES ELECTRICAL BREAKING IS USED.

27. ELECTRICAL BREAKING
 DYNAMIC BRAKING-WHERE MOTORS BECOME GENERATORS AND FEED THE
RESULTING CURRENT BACK.
 CLASSIFIED INTO THREE CATEGORIES-
1. PLUGGING
2. RHEOSTATIC BRAKING
3. REGENERATION
 PLUGGING- PLUGGING IS APPLIED BY CHANGING PHASE SEQUENCE OF
SYNCHRONOUS OR INDUCTION MOTORS.
 RHEOSTATIC BREAKING- MOTORS BECOME GENERATORS AND FEED RESULTING
CURRENT BACK INTO ONBOARD RESISTANCES.
 REGENERATIVE BRAKING- MOTORS BECOME GENERATORS AND FEED RESULTING
CURRENT BACK INTO SUPPLY SYSTEM.

28. LEADING TRACTION SYSTEMS AROUND
THE WORLD
 NOWADAYS MAGNETIC TRACTION IS BEING USED IN TRAINS (MAGLEV).
 SPEEDS UPTO 581 KMPH HAVE BEEN SUCCESSFULLY TESTED.
 SHINKANSEN (BULLET TRAIN) USES ELECTRICAL MULTIPLE UNIT
STYLE,OFFERING HIGH ACCELERATION AND DECELARATION.
 USES 25000 VOLTS OVERHEAD LINE.
 IT EMPLOYS AN AUTOMATIC TRAIN CONTROL SYSTEM (ATC),WHICH CONTROLS
ALL TRAIN MOVEMENTS ,TRACK ,STATION AND SCHEDULE ARE NETWOKED AND
COMPUTERIZED.

29. INDIAN RAILWAY
 4TH LARGEST NETWORK.
 EMPLOYS 1.6 BILLION PEOPLE.
 CONSUMES ONLY 1.7% OF TOTAL
OIL CONSUMPTION OF INDIA
,LARGELY DEPENDENT ON
TRACTION UTILITY.

30. CONCLUSION
 NO SINGLE MOTOR IS IDEAL FOR TRACTION WORK BUT DC SERIES MOTOR IS
MOST SUITABLE FOR ELCTRIC TRACTION.
 POWER ELECTRONICS HAS BEEN RESTORTED TO IN A MAJOR WAY FOR
CONVERSION AND CONTROL OPERATIONS.
 DIFFERENT TYPE OF BREAKING WERE DISCUSSED OUT OF WHICH REGENERATIVE
IS MOST EFFICIENT.
 IDEAL TRACTION SYSTEM SHOULD BE ABLE TO-
1. WITHSTAND SMALL VOLTAGE FLUCTUATIONS AND OVERLOADS FOR SMALL
PERIODS.
2. BRAKING SHOULD BE WITHOUT EXCESSIVE WEAR AND TEAR.
3. PARALLEL RUNNING(MORE THAN ONE MOTOR) SHOULD BE POSSIBLE.

31. REFERENCES-
 FUNDAMENTAL OF ELECTRIC DRIVE BY(G.K DUBEY)
 WIKIPEDIA (ELECTRIC TRACTION AND HIGH SPEED TRAINS)
 INDIAN RAIWAY OFFICIAL WEBSITE
 POWER ELECTRONICS BY (P.S BHIMBRA)

32. ANY QUERY ?