A GOVERNMENT OF WEST BENGAL ENTERPRISE
A PROJECT ON
LILUAH 132/33/25 KV SUBSTATION
PRESENTED BY:- PRABHAT KUMAR (EE/11/012)
ARIJIT DAS (EE/11/015)
DIPTESH KOLEY (EE/11/033)
We had a great pleasure in expressing our sincere gratitude to
the TPO of our college and Mr. D.Bose, GM(HR &
A),W.B.S.E.T.C.L for allowing summer training at Liluah
132/33/25 KV substation.
We are greatly thankful to Mr. Rakesh Kundu, assistant engineer
of Liluah transmission(O & M) substation for his immense help
and suitable guidance during training period.
We are also thankful to all other staffs of substation for their day
to day help and assistance.
It is the collector of electrical energy at one location at
Types:- 1. Rigid type: - made up of aluminium alloy tubes of 50
to 250 mm diameter and supported on post insulator with
clamps and connector.
2. Flexible type:- made up of A.C.S.R. conductor and
supported at both ends by strain insulators clamps and
Acts as common point when a number of generator or feeder
operating at same voltage is to be connected together.
TYPES OF ARRANGEMENT
1. Single busbar system
2. Duplicate busbar system
3. Triple busbar system
PROTECTIVE SCHEME IN
The capital investment involved in a power system for the
generation, transmission & distribution of electrical power is
so great that proper precaution must be taken to ensure
that the equipment not only operate as nearly as possible
to peak efficient but also that it is protected from accident
There are two main components of protection scheme:
1. Protective relay.
2. Circuit breakers.
1. Protective relay:- A relay is an automatic device which
senses an abnormal condition in an electrical circuit
and closes its contacts.
There are two operating principle of relay:
I. Electromagnetic induction.
II. Electromagnetic attraction.
Relays used for line protection :
(a) Earth fault relay (b) over current relay (c) distant protection relay
(d)Zone protection relay
Relays used for transformer protection:
(a)Earth fault relay. b) Over current relay. (c) buchholz relay
(d)differential relay (e)back up earth fault relay (f)restricted earth
fault relay (g)high temp relay (g)high temp relay (h)supervision relay.
• Isolate the faulty part of the power system in case of abnormal
•A protective relay detects the abnormal condition & sends a tripping
signal to circuit breaker. After receiving that relay trips the circuit and
circuit breaker isolates the faulty part
•In normal condition, the two contacts(fixed and moving) remain in
1. Oil circuit breaker
2. Air blast CBs
3. Sulphur hexafluoride CBs
4. Vacuum CBs
PROTECTION AGAINST LIGHTNING
The most commonly used devices for protection
against lightning surges are:
1. Earthing screen.
2. Overhead ground wires.
3. Lightning arrester or surge diverters.
An Isolator is a disconnecting switch being operated under the condition
of no load negligible current.
Used for disconnecting the circuit breaker from the circuit and to isolate
the electrical circuit at the time of maintenance work and repair.
Interlocking arrangement are generally provided in the isolators.
1. Vertical break type single, double and triple pole insulator
2. Horizontal two rotating post, centre break insulator
3. Horizontal break ,centre rotating double break insulator
4. Extra high voltage column insulator
These capacitors have an important role to investigate the
behavior of the breaker towards the restricting voltage.
1. Controls and improves the voltages.
2. Removes the reactive components of VARS component of the
power which is not desirable.
3. Improves power factor.
POWERLINE CARRIER COMMUNICATION
Protection signaling, speech and data transmission for
system operation and control, management information
system etc. are predominantly met by PLCC .
It is the most economical and reliable method of
communication because of higher mechanical strength
and insulation of high voltage power-lines which
contribute to the increased reliability of communication
and lower attenuation over the longer distances
b) Coupling capacitor
c) Line Matching Unit(LMU)
d) Protective equipments.
Provide unit charge to the entire system & behaves as back-up
In Liluah 132 KV substation these units provide control voltage of 220
VOLT DC back-up of entire system.
Makers- Amra Raja Make
Charging & discharging is needed to keep it healthy.
SL. No. : 4/2008/2
AC Input: 415± 10%
Ph: 50 Hz
DC Output to charge: 250 V
Cells at quick/boost: 2/2.7
A.P.L.: 60 A
V.P.C.: 1602 /480 M
An Earth Transformer is
connected in those areas
where earth point is not
available like a system
connected to delta side of
transformer, an artificial
neutral point is created
using earth transformer.
Sl.no Specifications Earthing Transformer 1 Earthing Transformer 2
1. Makers name GEC GEC
2. Std IS3151-1982 IS2026-1977
3. KVA Rating 100 100
4. Volts at no load HV:33KV,LV:415V HV:33KV,LV:415V
5. Amperes rating HV:1.75A,LV:139A HV:1.75A,LV:139.3A
6. Phases 3 3
7. Types of Cooling ON AN ON AN
8. Frequency 50 Hz 50 Hz
9. Vector group ZNyn-11 ZNyn-11
10. Impedance volt 4.5077% 3.796%
11. Earth fault current 550 A for 30 sec 287 amp for 30 sec
12. Year of mfg. 1990 1986
It is used to supply the Indian Railways. The Railways use 25 KV Single
phase line, so the Traction Transformer takes 2 phase 132 V Input supply
and gives 2 phase 25 KV Output out of which one phase is grounded and
made neutral and other phase is used by the Indian Railways.
Specifications Traction Transformer 1 & Traction
1. Maker’s Name Crompton Greaves Ltd.
2. MVA Rating 12.5/18.75
3. MVA (As per I.S) 13.5/20
4. KV Rating (at no load) H.V=132 KV;L.V=15KV
5. Line Current(Amps) H.V=102/151.5amp;L.V=500/750amp
6. Output Phase Single
7. Frequency(Hz) 50Hz
8. Type of cooling ON AN/ON AF
9. Total Oil(ltrs/kg) 15300/12900
10. Total Mass(Kg) 47600
11. Untanking Mass Core & winding=18900 kg
Bell tank=4200 kg
12. Heaviest Package With oil=33500 kg
Without oil=24800 kg
13. Hot Spot temperature Ref<1150C
14. Ambient temperature 45OC
15. Insulation level (H.V./L.V.) LI650AC275/LI250AC95
16. Guaranteed temperature rise of oil(0C) 50
17. Guaranteed temperature rise of winding(0C): 50
18. Maker’s w.o no.: T8174
19. Maker’s sl no.: 24749
20. Customer reference No.: LOI REF PLN/TRACTION/TRANS/491
21. Year of mfg: 06-04-1987
STATION SERVICE TRANSFORMER
Station Service Transformer converts HV 33 KV TO
LV 400KV which is used by the Substation for its own
needs like to run the air conditioner, fans and to run
the control panel and relay panel.
Maker’s Name: - Transmake Electrical Pvt. Ltd.
STD:- IS2026 & 1180
Volts at no load:-HV-33KV & LV-400V
Current at no load(A):-HV-1.75 & LV-144.34
Type of cooling:- ON AN
Frequency:- 50 Hz
Vector Group:- DYn11
Core & Winding weight:- 430 Kg
Weight of oil:- 260 Kg
Total weight:- 930 Kg
Oil quantity:- 300 Ltrs
Year Of Mfg:- 12/2002
Guaranteed Max temp. rise in oil:450C
Maker’s Name: - Bharat Heavy Electricals Ltd.
MVA Rating: - 30/40/50
Vector Symbol: - YnD1
Phase: - 3
Frequency: - 50 Hz
Type of cooling: - ON AN/ON AF/OF AF
Diagram Drg. no:-14561950473
Sl. No.:- 2013511
Year of mfg:- 2001
OLTC With oil, transport with oil heaviest package:- 50
Complete transformer including oil:- 97 Tonnes
Bil: HV:- 550 kvp & LV:-170 kvp
Impedance volts(at 750C):- 12.5 ± 13%
KV(No load):- HV-132 KV & LV-33 KV
Amps:- HV-218.95 & LV-875.81
At taps: normal tap(9b)
Maker’s Name:- ABB
Ref. Std: IS2026
Sl. No.: AAA-003
Year of mfg:- 2008
Frequency:- 50 Hz
Type of cooling:-ON AN/ON AF/OF AF
% Impedance Voltage HV/LV:
Nominal Power(ON AN/ON AF/OF AF):-30/40/50 MVA
Nominal voltage:- HV-132 KV & LV-33 KV
OLTC Type:- EASUNMR
Rated current:- 350 A
Insulation Ground:- 725 KV
Step Voltage:- 953 V
Control Voltage:- 110 V
Variation:- +10% to -10% of HV
No. of steps:- 16
Temp. rise of oil/winding:- 500C/550C
Vector Group:- YDn1
Short circuit current(max duration 3 sec):- HV=1.749 KA &
•% Impedance Voltage HV/LV:
Tap No. Guaranteed at N tap Actual (after test)
12.5% (± 10%)
Tap 9b 11.64%
Tap 17 11.33%
Testing Voltage HV HVN LV
Um(Highest sys V) 145 36
AC(Power frequency) 230 38 70
Lightning Impulse 550 95 170
•Core & Winding Mass:- 45670 Kg
•Tank & Fitting Mass:- 12520 Kg
•Oil Mass:- 17830 kg
•Total Transformer mass:- 76020 Kg
•Transformer mass(oil filled):- 68420 kg
•Total oil quantity:- 20030 litres
POWER TRANSFORMER 4
POWER TRANSFORMER 3
Oil level indicator