electric traction system ATUL GIRI, EN-E AJAY KUMAR GARG ENGINEERING CILLEGE.

1. ELECTRIC TRACTION
SYSTEM
Presented by:
ATUL GIRI
EN-E 4th year
1202721027

2. OVERHEAD
EQUIPMENTS This is an overhead wire of special cross
section. The contact wire is supplied at 25 KV;
50 Hz supply. AC voltage is trapped from contact
wire by pantograph.
 Stay Arm: It comprises of dia 28.4/33/7 mm (Small)
size tube and an adjuster at the end to keep the
bracket tube in position. It is insulated from the
mast by stay arm insulator.
 Bracket Tube: Catenary is supported from this
member by catenary suspension brackets and
catenary suspension clamp.
 Register Arm: It comprises of dia 28.4×33.7 mm
tube to register the contract wire in the desired
position with the help of steady arm

3.  Dropper is a fitting used in overhead equipment
construction for supporting the contact wire from
catenary.
 Neutral Section is defined as short insulated dead
overhead equipment separating sectors fed by two
adjacent substations which are normally connected to
different phases.
 Short Neutral Section – Section Insulator and PTFE .
The locomotive is switched off while negotiating the
neutral section to avoid flash over at the time of exit
and re-entering the live zone. For this, warning board
at 500M, 250M and final board for switching OFF and
ON are provided.
Neutral Section

4. SECTION
INSULATOR Section Insulator is a device installed along with the
contact wire for insulating two elementary sections
where the pantograph of the locomotive negotiates
smoothly and maintaining the current continuity.
 It is used in crossover, turnouts, maintenance pits
and yard line, etc. During movement of locomotive
pantograph, it first passes over the runner and
smoothly glides to the contact wire on the other side
without the break of continuity.

5. electrical continuity between contact and catenary
wires
jumper
Jumpers provided between out-of-run OHE and
anticreep wire as an anti-theft measure.

6. Booster Transformers
 Booster transformers are used in electric railway AC
catenary feeders to collect the return current from
the rails and the earth to the return conductor.
 Booster transformers are single-phase transformers
with the ratio 1:1. They have low impedance values,
but despite that, they must tolerate the stresses of
short-circuit currents.
 power ratings of booster transformers are 100-800
kVA. The nominal current is usually between 200A
...800 A.

8. Electrical Parameters of AC OHE system
Traction Supply Voltage:
Nominal Voltage: 25kV
Permissible Limits: 19.9kV to 27.5kV
Traction Supply Frequency:
Nominal: 50Hz
Permissible Limits: 48.5Hz - 51.5Hz
Traction Transformer Rating: 13.5MVA
Traction Transformer Resistance: 0.179Ω
Traction Transformer Reactance: 5

9. Power system installation
25 kV AC single phase
 For traction substation (TSS) the incoming EHV supply is
220/132/110/66KV through protective equipment it can
be transformed by using traction transformer to 25 KV AC
single phases.
 Spacing between TSS is 30 KM to 40 KM depending upon
the traffic (load).
 To avoid load on one phase and balancing the incoming
supply grid, the section TSS is divided into sub-sector
through switching posts.
1. S.P:- Sectioning and paralleling Post.
2. S.S.P:-Sub-sectioning and paralleling Post

10. Sectioning and paralleling post (SP)
 To facilitate the extension of traction power from one feed zone to half of the
adjoining feed zone during emergency.
 Parallel the UP and DN OHE in double the sections
Sub-sectioning and Paralleling post (SSP)
 Each section is subdivided into two or three subsection by the provision of SSP every 10-15
Km. This facilitates isolation of faulty sections.
 To sectionalize OHE
 To parallel the UP and DN OHE in double line sections.

11. POWER
TRANSFORMERThere are two traction transformer connected in parallel
of same rating for the purpose of reliability the rating of
transformer are
Capacity: 20,000 KVA. Frequency: 50 Hz
Full load: 25 KV Preferred: 0.9
Zero load: 27 KV

12. CIRCUIT
BREAKERS
220/132/110/66KV,double pole:
- Minimum oil type
- SF6 type
A circuit breaker is an automatically operated
electrical switch designed to protect an electrical
circuit from damage caused by overload or short
circuit
25kv,single pole
- Minimum oil type
- SF6 type
- Vacuum tube

13.  Lighting arrestors are provided to protect every sub-sector against voltage surges.
 Auxiliary transformers are provided at all the posts and also at certain intermediate points to
supply AC at 240 V, 50 HZ required for signalling and operationally essential lighting
installations. To ensure fairly steady voltage, automatic voltage regulators are also there,
where required.
 Potential transformers are provided at the various switching stations for monitoring supply
to each sub-sector.
Equipments at switching sections
 Buchholz relay is a safety device which is generally used in large oil immersed
transformers (rated more than 500 kVA). It is a type of oil and gas actuated protection
relay. It is used for the protection of a transformer from the faults occurring inside the
transformer,

14. Control
Equipments A Remote Control Centre (RCC) is set up near the traffic control office on each
division having electric traction to work in close liaison with the traffic control
 The RCC includes the main control room, equipment room, uninterrupted power
supply (UPS) room, remote control laboratory and battery room and is the nerve
centre of the traction power control.
 To segregate the faults and to isolate the faulty section, the circuit breaker at
traction substation and interrupters at SP/SSP’s are being remotely control through
remote control centre

15. The following types of remote control equipment are mainly in use on
Indian Railways at present
Frequency modulated voice frequency telegraph (FMVFT): This equipment was
in use for all electrification schemes prior to 1980. Being mainly all relay system, the
equipment has become outdated although some remote control centers still continue
to operate on this system
The FMVFT equipment has one send channel panel and receive channel panel. The
equipment works on 24v dc battery power supply
Supervisory control and data acquisition (SCADA) systems with
microprocessor: The SCADA equipment based on state of the art technology has
come into use after 1980. Considering the fast growth and development of computer
based equipment, newer types with enhanced capabilities are being introduced.
The SCADA equipment at the RCC is called master station while that of the controlled
station is referred as remote terminal unit (RTU).

16. SCADA
EQUIPMENTTRANSMISSION PATH:-
Underground telecommunication trunk cable is provided for transmitting the signals from and to
the RCC and controlled remote terminal unit.
REPEATER STATION:-
Voice frequency repeaters are provided at interval of 40-50km to boost the signal and to make the
good the line attenuation. The amplifier gain at the repeater station is about 20db, with an equalizer
incorporated to compensate up to 0.02db/khz/km.
MICROWAVE COMMUNICATION
In some of the sections on Indian railways dedicated microwave channel at carrier frequency of 18
GHz has been provided for the purpose of Communication.
OPTICAL FIBRE CABLE
Optical fibre cable has also been introduced for communication in some section of Indian railways,
which is also used for Remote Control equipment. Details of interface between latest
communication system and the RCC/RTU equipment may be seen in the relevant technical
document.

17. UPS and Batteries
at RCC1. Dual stand-alone UPS system of adequate capacity to supply 240V A.C., 50 Hz
single phase supply to the SCADA system at master station is provided. Both the
UPS work in parallel sharing the load.
2. In case of failure of one the entire load is automatically taken over by the healthy
UPS without affecting the working of the system.
3. In case of outage of both the UPS at the same time, the load of SCADA
equipment is directly connected to input main though a static switch without
any break.
4. A single battery is provided with both the UPS with adequate capacity to
provide the supply to various equipments is case of failure of input for 415V A.C.,
50 Hz supply.

18. Pantograph is a current collecting device which is
mounted on both ends of locomotive roof on
insulator and collect the current from Over Head
Extension and supply it to power system of locomotive
at various speed and different climate/wind condition
smoothly
Pantograph

19.  The traction motor is a dc series motor, four pole or six pole, forced ventilated machine
arranged for axle mounting on sleeve baring and supported on the opposite by the
resilient suspension unit, transverse movement is limited by the flanges of axle.
 These motors are axle hung, nose suspended type and are provided with grease
lubricated roller bearings for armature as well as for suspension.
 Special provision has been made in design of the motors to ensure the locomotive
operates satisfactorily on flooded track, to max. Flood level of 20 cm , above rail level
Traction Motors (DC Series
Motor)
Rating: A traction motor has following ratings:
Voltage - 285 volts
Current - 980 ampere
Speed - 360 rpm
Power - 248 kw

21. Thank you