ELECTRICAL ESTIMATION AND
COSTING
Module 5
Substations
• INDOOR SUBSTATION
1. Substations of the integrally built type
2. Substation of the composite built-up type
3. Unit type factory fabricated substations and metal
clad switch boards
• OUTDOOR SUBSTATION
1. Pole mounted substation
2. Foundation mounted substation
Selection and location of Site
• Type of Substation
• Availability of land
• Communication facility
• Atmospheric pollution
• Availability of essential amenities to the staff
Indoor Substation- Layout
Indoor Substation- Single Line Diagram
Out-door Or Pole Mounted Substation
33kV Substation
220/11KV Substation
Substation auxiliaries supply
Earth Mesh
Substation
Earthing
Earthing Electrodes
Earthing risers
Earthing connection
Problem 1
• A 37KW connection is to be given to an agriculture
field at 415 V, 3 Phase 50Hz. The connection is to be
given from a 3 phase 11 kV OH line which is available
at a distance of 40M. The motor has a full load
efficiency of 85% and power factor of 0.8.
•
•
•
•
•
Load (O/P)= 37kW
Load (i/p) = (37/0.85) = 43.53kW
Load KVA = KW/pf = 43.53/0.8 = 54.411kVA
Primary Side current = (54.41*1000)/Sq.rt of 3* Vp) = 2.855
Secondary side current = (54.41*1000/Sq.rt of 3 *Vs) = 75.695
• 63KVA, 11/0.433kV Delta to Start connected 3 Phase transformer.
• Al Armoured cable 3 ½ core, 25mm2 cable b/w transformer and the
agricultural motor room.
• ACSR 6/1 *2.11 conductor, b/w the transformer and OH line.
•
Length of cables
• ACSR conductor= 3*30+ 3*1(Wastage)+4*3(till the transformer)=
93m+12m=105m
• AI Armourd cable= 6+10+3+1+1 = 21m
Sl No
Description of the material
with full specification
Quantity required Rate
Amount
300
Remarks
HT Connection
1
MS Channel
100mm*50mm*7.5mm*
1.5m
1
300
2
ACSR 6/1 *2.11
conductor
93m or 9.3kg
160/kg
3
GI Wire 7/16 SWG
30+1=31=
3.1KG
270/kg
4
Disc type insulator
3
960
2880
5
Pin type insulator
3
300
900
6
Stay Set complete in all
aspects
1
2100
2100
7
Earth wire clamp
1
60
60
8
T clamp for MS Channel
1
600
600
10m = 1kg
Sl No
Description of the material
with full specification
Quantity required Rate
Amount
Remarks
Pole Mounted Substation
9
RS Joists
175mm*100mm*11m
long
2
7500
15000
10
11kV Lightning arresters
3 or 1 set
2000/each or
6000/set
6000
12
Disc insulator
3
960
13
GO Switch( Air break
triple pole switch) with
operating pipe and handle
1
7500
7500
14
Expulsion type fuse 11kV
installed with insulators
Insulators
3
960
2880
Fuses
3
800
2400
MS Angle (2m each)
3
150
450
MS Angle
10mm*50mm*6mm*2m
2
900
1800
15
Distance b/w the
two poles where
the transformer is
places is 2m
Sl No
Description of the material
with full specification
Quantity required Rate
Amount
19
PG Clamps
3
150
450
20
PG Bimetallic clamps
3
150
450
21
Al Armoured cable 3 ½ core,
25mm2 cable
3m
200
600
22
GI pipe
3
250
750
23
GI bend
2
75
150
24
Earthing set with plate
earthing
2
5500
11000
25
Stay rod set
2
2100
4200
26
Stay insulator
2
100
200
27
Binding Wires
0.5kg
270/kg
135
28
Danger plate
1
100
29
Number plate
1
100
30
Barbed Wires
5kg
31
Nuts and bolts
32
Concreating
50
250
200
2
1000
2000
Remarks
LT side of the
transformer
Sl No
Description of the material
with full specification
Quantity required Rate
Amount
21m
200
4200
Service Connection
33
Al Armoured cable 3 ½ core,
25mm2 cable
34
LT cable box indoor type with 1
all fittings
500
500
35
LT cable box for Outdoor
type
1
600
600
36
IC Cutouts fitted with fuse
and all the fittings
1 set
750
750
37
Meter box
25*30cm
1
400
400
45*60cm
1
1000
1000
3 Phase
1
3000
3000
1 PHASE
1
1200
1200
39
8 SWG GI Wire
21 or 2.1kg
300/kg
630
40
Nuts and bolts
150
41
Sand and Bricks
2000
38
Energy meter
Remarks
Sl No
Description of the material
with full specification
Quantity required Rate
Amount
Total
238463
Storage and Transportation (5%)
11923
Labour Charge (10%)
23846
Contingency (1%)
2384
Electrical inspection charge
3000
Grand Total
279617
Remarks
Problem 2
• Electric supply to a factory is taken from an
11kV overhead, 3 phase which is terminated at
2 pole structure at a distance of 20m from the
main board of the factory. The supply is to be
given through a 11/0.433kV transformer and
the factory has a load of 80 kVA. Estimate the
quantity of materials required and the total cost
Problem 3
• Estimate the quantity of materials and cost for
erection of a 250KVA pole mounted substation.
– Primary current = 250*1000/(sq.rt of 3 * 11000)
= 13.12A = ACSR conductor 7/2.11mm
– Secondary Current = 250*1000/(sq.rt of 3 * 415)
= 61/2.6mm, 1100V PVC cable
Problem 4
• Prepare the list of material required and
calculate the cost of installation of a 400kVA
indoor type 11/0.433kV transformer.
Sl No
Description of the material with full
specification
Quantity
required
Rate
Amount
1
400kVA, 11/0.433kV 3 Phase
transformer complete with all the
accessories.
1
400000
400000
2
XLPE insulated Al conductor
10mm2, 3 core 11kV cable
30m
800/m
32000
3
11kV outdoor terminal box
1
2700
2700
4
11kV indoor terminal box
1
1800
1800
5
GI pipe 76mm diameter heavy
gauge
5m
300/m
1500
6
Clamps for fixing cable pipe
10 no
80/each
800
7
Indoor type Oil CB, 11kV with
50/5 CT & accessories
1
150000
150000
8
Earthing of OCB
2
5200/earthi 10400
ng
9
Sand
5000
10
Bricks
15000
11
Slabs
100 nos
1600/each`
160000
Remarks
Trench
Sl No
Description of the material with full
specification
Quantity Rate
required
Amount
12
Empire tape
20 rolls 120
2400
13
HT tape
3
180
540
14
Foundation of Transformer
1
6000
6000
15
Earthing of Transformer
2
5200
10400
16
OCB FOR 415V 800A, 500/5 A
CT
Overload trip coil
1
75000
75000
17
LT cubicle board with locking
arrangement
1
125000
125000
18
LT Cable 3 ½ core
30m
1200/m
36000
19
Aluminum Lugs
16
300
4800
20
Earthing of LT panel
2
5200
10400
21
Fire extinguisher
1
10000
22
Shock treatment chart
1
200
23
First Aid box
1
1000
24
Miscellaneous
15000
Remarks
Sl No
Description of the material
with full specification
Quantity required Rate
Amount
Total
Storage and Transportation (5%)
Labour Charge (10%)
Contingency (1%)
Electrical inspection charge
Grand Total
3000
Remarks
Problem 5
• Estimate the quantity of materials and cost for
installation of10 MVA, 33/11KV substation
33kV Substation
• Instead of one 10 MVA transformer we will be
using two 5 MVA transformer.
Full load current at 33kV side
= 5000000/(sq.rt 3*33000)=87.5A
Full load current at 11kV side
=5000000/sq.rt 3 *11000)=262.5A
Sl No
Description of the material with full
specification
Quantity
required
Rate
Amount
1
5MVA, 33/11kV transformer with all
fillings and accessories
2
400000
800000
2
33kV GO switch complete all the
structure
3
75000
225000
3
33kV Lightning arrestors
1 set of 3
5000
5000
4
Power factor correction device 11kV
shunt type (Capacitive banks)
2
130000
260000
5
4 SWG hard drawn copper conductor
100m=
100 kg
400
40000
33kV line to
Bus bar
6
6 SWG hard drawn copper conductor
200m=
100kg
400
40000
33kV Bus bar
to Transformer
7
11kV 3 core XLPE 240mm2 Al
conductor armoured cable
50
3000
150000
Transformer to
Panel
8
Cable box, 33 kV, 3 core
4
1500
6000
9
Cable box, 11kV
4
1000
4000
10
11kV, 3 Phase, 50Hz metal clad switch
board
8 or 2 set
of 4
200000
1600000
OCB 400A, complete with CT and PT
Remarks
Sl No
Description of the material with full
specification
Quantity
required
Rate
Amount
11
Transformer platform
2
25000
50000
12
Cable trench
35m
600
13
Substation structure for GO switch,
Isolators, breakers
2 sets
38000
76000
14
33kV OCB
3
300000
900000
15
Control Cables 1.5mm2 copper cable
50m
500/m
25000
16
Earthing
26
5500
17
Empire tape
30 rools
150
18
HT tape
10
180
19
Jointing materials
16
600
20
Miscellaneous
Remarks
1 incoming 2
towards
transformer
4
(transformer)+6(3
33kV panels)+ 16
(8 11kV panels)
8 outgoing lines
15000
Sl No
Description of the material
with full specification
Quantity required Rate
Amount
Total
Storage and Transportation (5%)
Labour Charge (10%)
Contingency (1%)
Electrical inspection charge
Grand Total
3000
Remarks
Problem 6
• Estimate the quantity of materials required
and cost of installation of 132/33kV substation
with main and transfer bus scheme having
2*40 MVA transformer.
Sl No
1
2
3
4
5
Description of the
material with full
specification
Quantity required
Rate (Lakhs)
Amoun Remarks
t
(Lakhs)
132 kV
6
8.15
5+1(Bus Coupler)
33kV
10
2.3
9+1(Station
transformer)
132kV
17
0.62
3*5+2
33kV
18
0.34
7*2+2*1+1+1
132
5*3 Phase =15
1
33
9*3 Phase =27
0.25
132kV
3*3 Phase +1 Bus bar = 10
0.95
33kV
2
0.2
5
0.35
CB
Isolators
CTs
CVT
LA
132
Sl No
Description of the material
with full specification
Quantity required
Rate (Lakhs)
6
Post Insulators
90
0.09
7
Transformer
132/33kV
2
275
33/0.433kV
1
3.75
Control and relay panel
2
4.86
B/C panel
1
0.91
Double feeder panel
1
1.62
Distance protection panel
2
4.62
33kV triple feeder panel
3
2.5
9
Relay panel
1
5
10
Energy Meter
1
5.42
11
Control and Power cables
25
12
Structures
30
13
DC Equipment
3.5
8
Amoun Remarks
t
(Lakhs)
(Aproxima)
550
Control Panel
Sl No
Description of the material
with full specification
Quantity required
14
Bus bar and insulators
10
15
lighting on the control
room
12
16
Earthing mat and Earthing
30
17
Firefighting equipment
4
18
Boundary wall, Fencing,
Control room building
100
19
Land
40
Total
Spare 3%
Civil Wrk 5%
Transportation 5%
Supervision charges 25%
Erection 7.5%
Contingency 3%
T&P 1.5%
Grand Total
Rate (Lakhs)
Amoun Remarks
t
(Lakhs)
Assignment
• Estimate the quantity of materials required for
the augmentation of 33 kV grid substation of
500KVA to 1000 kVA, 33/11kV grid substation.
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