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WELCOME ABOUT
Installation, Testing & Commissioning of 800 KVA Sub-Station at
Euro Tech Bangladesh
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PREPARED BY :
Name: Ranjan Kanti Das ID-13305011
BSEEE-BACHELOR OF SCIENCE IN ELECTRICAL AND ELECTRONICS ENGINEERING
IUBAT-INTERNATIONAL UNIVERSITY OF BUSINESS AGRICULTURE AND TECHNOLOGY
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CONTENTS
 Introduction
 Objective
 Organizational Overview
 Sub-Station
 Single Line Diagram and Layout of 800KVA Sub-Station
 Room Lay-Out of 800 KVA Sub-Station
 Types of sub-Station
 Range of Low Voltage Sub-Station
 Equipment of 800KVA Sub-Station
 DOFC
 LA
 Different Part of a Transformer
 Technical Specification of 800KVA Sub-Station
 HT Switchgear
 LT Switchgear
 Power Factor Improvement
 Capacitor Bank of 480KVAR
 Transformer Meggar Test
 Earthing Test
 Bus-Bar
 LT Panel Bus-Bar Costing
 Recommendation
 Conclusion
 Questions
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INTRODUCTION
• Electrical power is the key of modern civilization.
• Power should be control and transfer.
• Power products helps to control & transfer power.
• Power products organization manufacture power products.
• Power products operation.
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OBJECTIVE
 Broad Objectives:
The Broad Objectives are mainly understand the Installation and operating of switchgear
devices for getting vast knowledge about it.
 Specific Objective:
 Collecting practical Knowledge regarding distribution substation.
 Study on Switchgear and protection in power system.
 To realize the organizational management system of Euro Tech Bangladesh.
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ORGANIZATIONAL OVERVIEW
Name:
Euro Tech Bangladesh
Established: 2003
Chairman:
Engr. Mohammed Rejaul
Islam
Ownership: ETB Group
Location:
H: 19, R: 11, S: 10 Uttara
Dhaka
Factory Location:
Damardi, Baiddar Bazar
Sonargaon, Narayangonj
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COUNT…….
Low Tension (LT)
Switchgear
High Tension (HT)
Switchgear
Transformer
Power Factor
Improvement (PFI)
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A sub-station is a part of an electrical generation, transmission and distribution system.
Sub-station transforms voltage from high to low between the generating station and
consumers, electric power may flow through several substations at different voltage
levels.
SUB-STATION
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SINGLE LINE DIAGRAM OF 800 KVA SUB-STATION
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ROOM LAY-OUT OF 800 KVA SUB-STATION
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TYPES OF SUB-STATION ON THE BASIS OF DESIGN
Sub-Station
Indoor Sub-Station Outdoor Sub-Station
Foundation Mounted
Sub-Station
Pole Mounted Sub-Station
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RANGE OF LOW VOLTAGE SUB-STATION
Sub-Station Rating Protection
100 KVA
HT Not Used
150 KVA
200 KVA
250 KVA
315 KVA HT Used with LBS
(Load Break Switch)
400 KVA
500 KVA
630 KVA
HT Used with VCB
(Vacuum Circuit Breaker)
750 KVA
800 KVA
1000 KVA
1250 KVA
1500 KVA
2000 KVA
2500 KVA
3000 KVA 12

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EQUIPMENT OF 800KVA, 11/0.415 KV SUB-STATION
 11 KV, Dropout Fuse Circuit (DOFC)
 11 KV, Lighting Arrester (LA)
 800 KVA Distribution Transformer
 630A, HT Switchgear
 1250A, LT Switchgear
 480 KVAr, PFI Plant
 Earthing for Sub-Station
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 DOFC is a combination of a fuse and a switch.
 Used in primary overhead feeder lines and to
protect distribution transformers from current surges and
overloads.
Technical Specification:
Rated Voltage (Nominal) : 11KV
Rated Maximum Voltage : 15KV
Rated Frequency : 50Hz
Rated Current (RMS) : 100A
DROPOUT FUSE CIRCUIT (DOFC)
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A lightning arrester is a protective device which conducts
the high voltage surges on the power system to the ground.
Technical Specification:
Rated Voltage (RMS) : 12KV
Frequency : 50Hz
Minimum spark over voltage(RMS) : 14KV
LIGHTING ARRESTER (LA)
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DIFFERENT PARTS OF A TRANSFORMER
Figure: Different Part of 800KVA Distribution Transformer
Conservator
Silica gel
HT Terminal
LT Terminal
Name Plate
Radiator
Tank
Earthing Point
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SWITCHGEAR
630A, HT Switchgear 1250A, LT Switchgear 17

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HT SWITCHGEAR
Line In
KV
A IDMT
Relay
Connection
CT
CT
CT
PT PT
Inner Part Upper Part
Isolator
H
a
n
d
l
e
VCB
A Selector KV Selector
3-phase Line In
3-phase Line Out
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TECHNICAL SPECIFICATION OF HT SWITCHGEAR
1 no. 11KV, 630A, TP spring charged energy mechanism operated fixed type Vacuum
Circuit Breaker (VCB).
3 no. 11KV, Current Transformer (CT) having ratio 60/5/5A, for metering & Protection.
2 no. 11KV, Potential Transformer (PT) having ratio 11000/110V.
1 no. Triple pole IDMT relay for the Over Current, Short Circuit and Earth Fault
Protection.
3 no. Indication Lamp.
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LT SWITCHGEAR
Line In Line In
KA V
MCCB/ACB
MCCB/ACB
Line In
MCB MCB
Line Out
CT CT CT
CT
Inner Part Upper Part
KA Selector V Selector
H
a
n
d
l
e
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Incoming:
1 No. 1250A, TP MCCB with adjustable thermal overload & short circuit protection.
4 Nos. Current transformer having ratio 1250/5A with suitable accuracy & burden.
1 No. Ammeter having scale 0-1250A with selector switch.
1 No. Voltmeter having scale 0-500V with selector switch.
3 No. Phase indicating lamps.
Outgoing:
1 no. 800A, TP MCCB with thermal over load and magnetic short circuit releases.
2 no. 400A, TP MCCB with thermal over load and magnetic short circuit releases.
1 no. 300A, TP MCCB with thermal over load and magnetic short circuit releases.
1 no. 100A, TP MCCB with thermal over load and magnetic short circuit releases.
TECHNICAL SPECIFICATION OF LT SWITCHGEAR
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Power Factor: The value of the cosine (cosθ) between the voltage and the current is called the power
factor.
POWER FACTOR IMPROVEMENT
Voltage
Current
Improving power factor means reducing the phase difference
between voltage and current. Since majority of loads are of
inductive nature, they require some amount of
reactive power for them to function. This reactive power is
provided by the bank of capacitors installed parallel to the load.
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Line In Line In
Power Factor
Regulator
Power Capacitor
Magnetic Contactor
HRC Fuse
PC
HRC Fuse
HRC Fuse
M.C.
HRC fuse
Inner Part Upper Part
PFI PANEL
H
a
n
d
l
e
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480 KVAR CAPACITOR BANK
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1 no. 12 stages automatic power factor correction relay with auto/manual selector switch,
indication lamp & digital P.F. meter.
08 No. 50KVAr, 415V, TP dry type power capacitor bank with built in discharge resistor.
02 No. 25KVAr, 415 V, TP dry type Power capacitor bank with built in discharge resistor.
01 No. 15KVAr, 415V, TP dry type Power capacitor bank with built in discharge resistor.
01 No. 5KVAr, 415 V, TP dry type Power capacitor bank with built in discharge resistor (Fixed )
12 No. TP, 415V Magnetic contractor of adequate rating.
39 No. HRC fuses with base of adequate rating.
12 No. Indication Lamps.
TECHNICAL SPECIFICATION OF PFI PANEL
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MAGNETIC CONTACTOR AND FUSE SELECTION DEPENDING
ON KVAR
Sl Capacitor Stage of Controller
Magnetic
Contactor(Amp)
Fuse (Amp)
1 5 KVAR Fixed/Direct 12A 14 A
2 10 KVAR 1 25A 30 A
3 15 KVAR 2 32A 40 A
4 25 KVAR 3 40A 63 A
5 25 KVAR 4 40A 63 A
6 50 KVAR 5 85A 125 A
7 50 KVAR 6 85A 125 A
8 50 KVAR 7 85A 125 A
9 50 KVAR 8 85A 125 A
10 50 KVAR 9 85A 125 A
11 50 KVAR 10 85A 125 A
12 50 KVAR 11 85A 125 A
13 50 KVAR 12 85A 125 A 26

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Here the insulation resistance varies the different condition. Mainly in transformer have
three special part LT winding, HT winding, and Transformer body. That should be like
that value
• HT- LT: 2000MΩ
• HT- Body: 2000MΩ
• LT- Body: 2000MΩ
TRANSFORMER MEGGAR TEST
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EARTHING TEST
Earthing Metarials:
 Earthing conductor size should be 2-4 SWG
 Earthing result will be less than 1 ohm
 LA and X-F neutral grounding should be separated from the main mesh
 Depth of LA & X-F neutral grounding boring point at least 25 M
 X-F body will be grounded at least 2 points
Earthing Test (Earth Tester No: 26180204)
 Earthing resistance in Electrode-1 = 0.93 Ohm
 Earthing resistance in Electrode-2 = 0.88 Ohm
 Earthing resistance in Electrode-3 = 0.86 Ohm
 Earthing resistance in Electrode-4 = 0.92 Ohm
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BUS-BAR
Bus-Bar is a type of electrical junction in which all the incoming and outgoing electrical
current meets. Thus, the electrical bus bar collects the electrical energy at one location.
LT Panel Bus-Bar Selection:
We will multiply incoming breaker capacity 1250A by 1.25.
1250 × 1.25 = 1562.5 A
We know that,
2 Amp = 1 mm2
1562.5 A = 781.25 mm2
So according to 781.25 mm2 we need (65 ×12) mm2 Bus bar but this is not available in
market so we will take (70×12) mm2.
N.B: A little or more increasing is good for Bus bar but not decreasing from rated value.
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LT PANEL BUS-BAR COSTING
We need 1 m length bus bar then
N.B.: Here we choose (70×12) mm2 Bus bar
L = 1 m = 1000 mm
W = 70 mm
H = 12 mm
So,
V = L x W x H
V = (1000× 70× 12) mm3
V = 840000 mm3
V = 0.00084 m3
Now we know that the density of
cupper is,
ρ = 8960 kg/m3
So Mass,
m = ρ v
m = 8960 kg/m3 × 0.00084 m3
m = (7.5) kg
Let,
1 kg = 800 Tk.
7.5 kg = 6000 Tk.
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RECOMMENDATION
 To avoid fault in Substation, ELB should take care of overall test on substation like, Transformer
magger test, Dimension of substation equipment, Earth test etc.
 Transformer oil and silica gel should be checked after one month or any type of fault. Oil should be
changed if it is decomposed.
 Need separation between Transformer and LT switchgear for their safety purpose.
 Depends on ambient temperature we should manufactured transformer for in terms of area, to
minimize cost.
 The direct capacitor which used in PFI, it should be used low rating capacitor to avoid assess by
DESCO, BREB, DPDC etc.
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CONCLUSION
For a technical service provider plant I&C activities are very important as its service
mostly depends on the availability of its equipment. By using proper I&C schedule of
substation cost can be reduced and supply can be increased. I&C are traditionally
classified as a part of output that comes from the system. During my internship, I could
learn about Substation on, its Installation, Testing and Commissioning. During this study,
it has been observed from the organizational point of view where it has been
implemented.
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