SEMINAR-2015 (abhishek)

MODERN TRENDS IN TRACTION SYSTEM OF
INDIAN RAILWAYS
Department of Electrical and Electronics Engineering
8th semester, B.E.
BY:-
ABHISHEK KUMAR
USN:-2SD11EE002
Presenting Seminar On
Subject code:-EE451
Date:-09-02-2015

Contents
 Introduction
 Working of traction system in INDIA
 Modern trends
I. Electrification
II. Conversion of 25kv system to 2×25kv system
III. Conversion of DC motor to AC motor
IV. Modernization of Equipment
V. Regenerative braking
VI. Use of SCADA and PLC
 Conclusion
2

 Rail transport in India began in the year 1853 from Bombay
to Thane.
 It is one of the world's largest railway networks comprising
115,000km of track over a route of 65,436 km and 7,172
stations.
 IR operates both long distance and suburban rail systems
on a multi-gauge network of broad(5 ft 6 inch),
metre(3ft 3 3⁄8 in) and narrow gauges(4 ft 8 1⁄2 in).
 Presently IR is working on three system 1500V AC system
and 25kv AC system and diesel engine system.
 Loco’s are designed by CLW,BHEL,TELCO.
3
Introduction

 Considering electric system there are 1500V dc and 25KV ac sys.
 The LOCO’s gets electricity supply through an overhead system of
suspended cables known as the catenary or OHE.
4Working of traction system in INDIA

5Working contd.
 The loco uses a pantograph(a metal structure which can be raised or
lowered) to make contact with the OHE cable.
 This pantograph collects the current from OHE and than through
transformer and other devices it goes to Motor.
 there are typically 4 or 6 traction motors in a locomotive.

 The return path is through body of the loco and wheels to the track
which are electrically grounded.
 Ground connections are provided from the rails at periodic intervals.
6Working contd.

7I. Electrification
Electric traction was introduced on 3rd February 1925.
Now 60 % of the total lines are electrified.
Considering electrical sys Mainly there are two system
presently working in India
1500V dc system
25 KV ac system
Latest trends is to convert the whole system into one 25kv
system means to convert all the dc system into 25kv ac
system.
 Advantage of Electrification :-
1. Higher acceleration and braking features for
frequent starts and stops (mainly for EMU).
2. Haulage of Heavier Freight Trains and Longer
Passenger Trains under Electric Traction.
3. Pollution free atmosphere.
4. Regenerative braking.

8Diesel Loco’s block Diagram

9Electric Loco’s block Diagram

10II. Conversion of 25kv system to 2×25kv
system
 There is 3 possible arrangement. Single system (AC) , Booster
Transformer (BT) System , Autotransformer (AT) System / 2 x 25kV System
/ 'Dual' System.
 The first two system is now being upgraded to 2×25 kv system.

12
1. Single AC system & Booster Transformer (BT) System:
 suffer from voltage drops along the length of the
catenary(by 5kv or more).
 More no. of substations (placed 35-60km apart
along the route). The substations are spaced
more closer (down to 10-20km) in areas where
there is high load / high traffic.
 In booster transfer system extra cost of
transformer increases the cost of system.

13ADVANTAGE OF 2×25KV SYSTEM
Improved voltage regulation and reduced
transmission line losses.
Increased traction substation spacing.
Improved load factor as number of trains fed
per feeding post are more.

14III. Conversion of DC motor to AC motor
Direct current motors with series field windings were the
oldest type traction motor.
Problems :-
1. speed control is done by tap changer on transformer or
resistance control and later by thyristor
2. high current low voltage design(750 V, 1000A) which
calls for expensive large diameter cables.
3. Restricted speed 2500 rpm.
4. Low power to weight ratio.
5. Need more maintenance(commutator, brush etc.)
6. More cost than a ac motor

AC motor :-Now latest trends is to use AC motor(3-phase
squeral cage indiction) in place of DC motor where all the
problems of dc has
Problem :-speed control
N=
𝟏𝟐𝟎×𝑭
𝑷
{where f is frequency and p is no
of pole}
Solution is to convert the ac into dc and again convert
the dc into ac so that The microprocessor controller can
vary the switching of the thyristors produce AC of a wide
range of frequencies and voltages and Various kinds of
thyristor devices are used to perform the switching.

16
 High power to weight ratio
 can easily operate at 4000 rpm no restriction of speed as
in dc motor( upto 2500rpm).
 High voltage and low current 2800 V, 300A. Results
heavy reduction in operating current, power cables are
much lighter and losses are reduced.
 regenerative braking can be used.
 robust and require little maintenance.
Advantage of AC motor over DC motor

17IV. Modernization of Equipment
 To bring down the maintenance cost and improve
the reliability of power supply system,
a. Use of Sf6 circuit breaker
b. Use of dry cast resin transformer
c. 8 wheeler self-propelled OHE inspection cars have
also been introduced to improve maintenance.

18
a. Use of dry cast resin transformer
 The main advantage of this type of transformer over the oil filled
ones is that they are practically maintenance free.
 The copper in the windings cannot be retrieved from the cast resin
and so the risk of theft is eliminated.
 There being no oil risk of fire and explosion are also absent.
 Dry cast resin transformers are currently under evaluation for their
service performance.

19
D. Conversion of semaphore signal system in colour LED signal.

20Use of LHB coaches at the place of old ICF coach
Advantages:-
 Microprocessor enabled ac
 Light weight high speed
 Plug point in all compartment
 do not get turned over or flip
in case of a collision
ICF rake LHB rake

21V. Regenerative braking
Regenerative braking works on the principle of converting th
e kinetic energy of the locomotive (and train) back
to electricity by using the
traction motors in reverse (as generators) and feeding the el
ectricity back to the OHE.
The newer AC locos have microprocessor control which
helps enormously as the waveform and phase of the
regenerated power can be adjusted precisely.
it is operated as a generator during braking and its output is
supplied to an electrical load; the transfer of energy to the
load provides the braking effect.
It can save 10% or more of the electricity costs if used in
busy traffic.

22VI. Use of SCADA and PLC
 220 / 132 / 25 kV power supply network for electrification extending
along the track over a zone of about 200/300 km is centrally controlled
from the division control center through remote control arrangements.
 Supervisory Control and Data Acquisition (SCADA) offers ease of
monitoring sensors placed at distances, from one central location.
 It consists of two main part RTU(remote terminal unit, RCC(Remote
Control Center).
 The RCC does the work of a supervisor and controls the activities of a
network through RTUs.
 Several RTUs are required for interfacing with other elements of a
network as a power network is very huge.
 The end devices which are to be monitored are interfaced with the RCC
through the RTU.
 This information is queried by the RCC and the RTU uploads the
information when required.
 This information that is collected from the RTUs is kept in databases and
is displayed through the GUI at RCC.
 The RCC configures and controls the RTUs

24Conclusion
 As discussed above all the steps taken by
Indian railways for up gradation.
 As a result of all above steps IR is been
upgrading at a faster rate
 specially Electrification of existing un-electrified
line is being done to adopt many new
technology like regenerative braking, ac loco
witch is less maintenance ,rugged.
 There are lots of research are going on to
upgrade the railway .

SEMINAR-2015 (abhishek)

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