Date post: | 07-Jul-2018 |
Category: |
Documents |
Upload: | naresh-pattanaik |
View: | 219 times |
Download: | 1 times |
8/18/2019 Grounding design basis
http://slidepdf.com/reader/full/grounding-design-basis 1/26
2x660 MW IB TPS (UNIT-3 4), BANHARPALLI
Design Memorandum For Grounding System
Doc. No. PE-DC-391-509-E002
Revision 0
2
DEVELOPMENT CONSULTANTS
PRIVATE LIMITED
Reviewed for general conformance with Contractdrawings and specifications.
ACTION : 1
1 Approved 4 Disapproved.
2 Approved except asnoted. Forward finaldrawing.
5For information/referenceonly.
3 Approved except asnoted. Resubmissionrequired.
Blank
Approval of Contract documents by the Consultant shallnot relieve the Seller of his responsibility for any errorsand fulfilment of Contract requirements.
Digitally signed by Shouvik Patari
DN: cn=Shouvik Patari, o=DCPL,
ou=DCPL,
m, c=IN
Date: 2014.01.30 16:08:27 +05'30'
8/18/2019 Grounding design basis
http://slidepdf.com/reader/full/grounding-design-basis 2/26
Design Memorandum For Grounding System2x660 MW IB TPS (UNIT-3 & 4), BANHARPALLI
Doc. No. PE-DC-391-509-E002
Rev No: 0
Date: 19.02.13
INDEX
S. No. DESCRIPTION SHEETNO.
1. SCOPE 3
2. DESIGN PHILOSOPHY – BELOW GRADE GROUNDING 3-4
3. DESIGN PHILOSOPHY – ABOVE GRADE GROUNDING 4-5
4. REFERENCES 5
5. ANNEXURE-A1: CALCULATIONS OF GROUNDINGCONDUCTOR SIZE
ANNEXURE–A2: ETAP REPORT –GROUND GRID INPUTDATA & RESULTS
6-7
8-10
6. ANNEXURE-B: MATERIAL AND SIZE DETAILS OF BELOWGRADE AND ABOVE GRADE GROUNDING SYSTEM
11-14
2
02.01.14
14
15-18
(i) SAMPLE CALCULATION 19
8/18/2019 Grounding design basis
http://slidepdf.com/reader/full/grounding-design-basis 3/26
Design Memorandum For Grounding System2x660 MW IB TPS (UNIT-3 & 4), BANHARPALLI
Doc. No. PE-DC-391-509-E002
Rev No: 0
Date: 19.02.13
1.0 SCOPE
1.1 This document covers the design of below and above grade grounding system forthe main plant area of 2x660 MW IB TPS (UNIT-3 & 4), BANHARPALLI.
1.2 The following aspects of below grade grounding system design are covered:(a) Determination of size of ground conductor.
(b) Establishing the ground grid configuration.(c) Determination of ground grid resistance.(d) Check on Step and Touch potential.
1.3 The methodology and material details of above grade grounding system are alsocovered in this document.
1.4 The following calculations/ details are not covered in this document:
(a) Grounding for switchyard areas (OPGCL Scope).(b) Grounding for Coal Handling area / Ash Handling area (CHP & AHP vendor
Scope).(c) Grounding for plants & facilities not part of Main Plant Package.
Further, interconnection of aux. Plants/ other areas grounding grid with mainplant grounding grid shall be in Customer’s scope inline with Cl. 2.1.2 below.
2.0 DESIGN PHILOSOPHY OF BELOW GRADE GROUNDING SYSTEM
2.1 Type of grounding
2
02.01.14
8/18/2019 Grounding design basis
http://slidepdf.com/reader/full/grounding-design-basis 4/26
Design Memorandum For Grounding System2x660 MW IB TPS (UNIT-3 & 4), BANHARPALLI
Doc. No. PE-DC-391-509-E002
Rev No: 0
Date: 19.02.13
details of electronic grounding, system supplier, BHEL/EDN documentation shallbe referred.
2.1.6 All system neutrals (including neutrals of power transformers), groundingterminals of EHV surge arrestors and EHV voltage transformers are connected totwo nos. treated test pits, which in turn are connected to the ground grid.
2.1.7 All lightning protection down conductors are connected to dedicated groundelectrodes through isolating links and then to the grounding system.
2.1.8 The sizes of conductors for below grade grounding are tabulated in Annexure-C,Table-1.
2.2 Design Criteria
2.2.1 Average soil resistivity has been computed based on Soil Resistivity Measurements(Test results are attached at Annexure-D) furnished by OPGCL as part of ContractSpecification “ Vol-A: Geo technical Investigation Report”.
2.2.2 The size of grounding conductor is based on the maximum ground fault currentvalue of 50 kA for 1 second, with all below grade joints being welded type. Theminimum rate of corrosion of steel for selection of grounding conductor isconsidered as 0.12 mm per year. The grounding grid has been sized for a power
plant life of 40 years.
2.2.3 For a fault located within power station premises, the ground grid design is basedon the maximum fault current that is expected to occur during the design life of
2
02.01.14
8/18/2019 Grounding design basis
http://slidepdf.com/reader/full/grounding-design-basis 5/26
Design Memorandum For Grounding System2x660 MW IB TPS (UNIT-3 & 4), BANHARPALLI
Doc. No. PE-DC-391-509-E002
Rev No: 0
Date: 19.02.13
3.1.3 75x10 mm galvanised M.S. flats are run as main earth conductor along buildingcolumns / walls and securely fixed to the same by welding / clamping at intervalsnot exceeding 750 mm. Connections from runway conductor/submats are made tothe main earth conductor.
3.1.4 Railway tracks are bonded across fish plates and earthed at regular intervals. Atthe point where rail track leaves plant area, the rail section is provided with
insulated joint at both ends.
3.1.5 Metallic hand rails, fencing of transformer yard, etc. are connected to the belowground earthing system. Earthing conductor is buried at least 2000 mm outsidethe fence of electrical installations. Every alternate post of the fences and all gatesare connected to earthing grid by one lead.
3.1.6 Each street lighting pole/flood light pole and lighting mast will be grounded by
35x6 mm GS flat, which will be connected to two no. 40 mm dia & 3m longearthing spike, directly driven into ground at a depth of 1 meter from groundlevel. The junction box at each lighting pole is grounded at two (2) points fromtwo (2) nos. earthing terminals by 16 SWG GI wire. One 16 SWG GI wire shall betaken upto the junction box from lighting fixtures and connected to groundingpoint.
3.1.7 Cable screens and armour (wherever applicable) are earthed at both ends for
multi core cables. For single core cables, the same is done at switchgear end only.
3.1.8 Above grade ground conductor connections are welded except at the equipmentend, where the connections are bolted.
2
02.01.14
8/18/2019 Grounding design basis
http://slidepdf.com/reader/full/grounding-design-basis 6/26
ANNEXURE- A1
CALCULATION OF GROUNDING CONDUCTOR
SIZE
8/18/2019 Grounding design basis
http://slidepdf.com/reader/full/grounding-design-basis 7/26
Doc. No. PE-DC-391-509-E002
Rev No. 00
CALCULATION OF GROUNDING CONDUCTOR SIZE Annexure-A1
As per equation 40 of IEEE-80-2000 cross sectional area of earthing conductor shall be:
A (mm2)= I x sqrt [ {( tc x r x r x 104)/ TCAP}/ ln { (K 0 + Tm)/ (K 0 + Ta)}]
where,
A= Conductor cross section in sq. mm.I= Ground fault current (rms) in kA = 50 kA
tc= Time of flow of current = 1 sec.r= Thermal coefficient of resistivity = 0.00423 deg. C
(for mild steel as per CBIP manual TR-5) at 20 deg. C
r= = 15 micro-ohm cm
(for mild steel as per CBIP manual TR-5)
TCAP = Thermal capacity factor in J/cu.cm./ deg.C= 4.184 x SH X SW [As per Eq. 39 of IEEE-80-2000]
SH = Specific heat in Cal/gm/deg. C = 0.114
(for mild steel as per CBIP manual TR-5)SW = Specific weight in gm/cc = 7.86
(for mild steel as per CBIP manual TR-5)Hence,
TCAP = 4.184 x 0.114 x 7.86 = 3.749
Tm = Max. allowable temp. = 620 deg. C
(for mild steel as per CBIP manual TR-5)
Ta = Ambient temperature = 50 deg. C
Tr = Reference temperature 20 deg. C
Design Memorandum For Grounding System
2x660 MW IB TPS (UNIT-3 & 4), BANHARPALLI
Ground conductor resistivity
19.02.13
2
02.01.14
8/18/2019 Grounding design basis
http://slidepdf.com/reader/full/grounding-design-basis 8/26
ANNEXURE- A2
ETAP REPORT –GROUND GRID INPUT
DATA & RESULTS
8/18/2019 Grounding design basis
http://slidepdf.com/reader/full/grounding-design-basis 9/26
Location: BANHARPALI
Engineer: VKS Study Case: GRD1
5.5.6C
Page: 1
SN: BHARATBHEL
Filename: OPGCL
Project: 2X660 MW BANHARPALI TPSETAP
Contract: 391
Date: 02-01-2014
IEEE Std 80-2000
Number of Ground Conductors: 31
Number of Ground Rods: 60
Total Length of Ground Conductors: 9614.00 m
Total Length of Ground Rods: 180.00 m
Ground Grid Systems
Electrical Transient Analyzer Program
8/18/2019 Grounding design basis
http://slidepdf.com/reader/full/grounding-design-basis 10/26
Location: BANHARPALI
Engineer: VKS Study Case: GRD1
5.5.6C
Page: 2
SN: BHARATBHEL
Filename: OPGCL
Project: 2X660 MW BANHARPALI TPSETAP
Contract: 391
Date: 02-01-2014
Ground Grid Input Data
System Data:
kg
for
Factor Fault
Factor
CpSf TsTc
kA
Total
Body CurrentConductorsDuration°CAvailable
for
Tf
Ground
for Sizing
Total Fault
Fault Duration (Seconds)
%
Projection
%
Division
X/R
Short-Circuit Current
Current Ambient Temp. Weight Freq.
Hz 50.0 50 50.00 14.0038.880 1.00 1.00 1.0073.4 100.0
Soil Data:
mm m mm Resistivity
Lower Layer Soil
Resistivity Depth
MaterialType Material Type
Upper Layer Soil
Depth Resistivity Surface Material
Material Type Clean limestone 3000.0 0.15 Moist soil 50.0 1.00 Moist soil 50.0
Type %
Conductivity
1/°C
@ 20 °C
r Factor
K0 @
0 °C
Temperature
Fusing
°C
Resistivity of Ground Conductor
@ 20°C .cm
Capacity
Per Unit Volume
J/(cm³.°C)
Thermal
Conductor/Rod
Material Constants:
Mild Steel, MS 10.8 0.00423 216.4 620.0 15.00 3.75Conductor & Rod
8/18/2019 Grounding design basis
http://slidepdf.com/reader/full/grounding-design-basis 11/26
Location: BANHARPALI
Engineer: VKS Study Case: GRD1
5.5.6C
Page: 3
SN: BHARATBHEL
Filename: OPGCL
Project: 2X660 MW BANHARPALI TPSETAP
Contract: 391
Date: 02-01-2014
Ground Grid Summary Report
%
Calculated %
CalculatedPotential Rise
Rg Step Potential Touch Potential
Volts VoltsVoltsVolts Tolerable Calculated Tolerable Calculated
Volts Ground
GPR
Ohm Resistance Ground
0.076 2209.9 338.7519.5 107.31730.265.2 6.2
Total Fault Current: 38.880 kA Reflection Factor (K): -0.967
Maximum Grid Current: 29.167 kA Surface Layer Derating Factor (Cs): 0.773
Decrement Factor (Df): 1.022
Grid area is smaller than 6.25 m² or greater than 10,000 m²
Report of Intermediate Constants for IEEE 80 Methods
- Correction factor for grid geometry regarding touch voltage (Kim): 2.891
- Correction factor for grid geometry regarding step voltage (Kis): 2.891
- Spacing factor for touch voltage (Km): 0.795
8/18/2019 Grounding design basis
http://slidepdf.com/reader/full/grounding-design-basis 12/26
One-Line Diagram - OLV1 (Short-Circuit Analysis)
Gr i d1
Bus1
21 kV 8. 8
9 7 k V
Bus2
21 kV 8. 8
9 7 k V
Bus3
400 kV5 0 .0 k A
43. 8
U130346 MVAsc
3. 1
62. 07
Gen Uni t #2
660 MW
GCB- 2
T2
810 MVA
HVCB- 2
3. 1
62. 07
Gen Uni t #1
660 MW
GCB- 1
T1
810 MVA
HVCB- 1
Gr i d1
U130346 MVAsc
660 MWGen Uni t #2
660 MW
T1
810 MVA T2
810 MVA
Bus1
21 kV
Bus3
400 kV
Bus2
21 kV
Gen Uni t #1
5 0 .0 k A
8. 8 9 7
k V
43. 8
3. 13. 1
HVCB- 1 HVCB- 2
GCB- 1
62. 07
8. 8 9 7
k V
GCB- 2
62. 07
8/18/2019 Grounding design basis
http://slidepdf.com/reader/full/grounding-design-basis 13/26
One-Line Diagram - OLV1 (Short-Circuit Analysis)
Gr i d1
Bus1
21 kV 8. 8
8 k V
Bus2
21 kV 8. 8
8 k V
Bus3
400 kV
244. 3 9
k V
4 4 .6 6 k A
25. 89
U130346 MVAsc
9. 4
0
0
Gen Uni t #2
660 MW
GCB- 2
T2
810 MVA
HVCB- 2
9. 4
0
0
Gen Uni t #1
660 MW
GCB- 1
T1
810 MVA
HVCB- 1
Gr i d1
U130346 MVAsc
Gen Uni t #1
660 MWGen Uni t #2
660 MW
T1
810 MVA T2
810 MVA
Bus1
21 kV
Bus3
400 kV
Bus2
21 kV
244. 3 9
k V
4 4 .6 6 k A
8. 8 8 k
V
0
25. 89
9. 49. 4
HVCB- 1 HVCB- 2
GCB- 1
0
8. 8 8 k
V
0
GCB- 2
0
8/18/2019 Grounding design basis
http://slidepdf.com/reader/full/grounding-design-basis 14/26
One-Line Diagram - OLV1 (Short-Circuit Analysis)
Gr i d1
Bus1
21 kVBus2
21 kV 9. 0
5 k V
Bus3
400 kV
2 5 2.6 k V
3 8 .8 8 k A
28. 54
U130346 MVAsc
10. 36
0
0
Gen Uni t #2
660 MW
GCB- 2
T2
810 MVA
HVCB- 2
Gen Uni t #1
660 MW
GCB- 1
T1
810 MVA
HVCB- 1
NO
Gr i d1
U130346 MVAsc
Gen Uni t #1
660 MWGen Uni t #2
660 MW
T1
810 MVA T2
810 MVA
Bus1
21 kV
Bus3
400 kV
Bus2
21 kV
2 5 2.6 k V
3 8 .8 8 k A
28. 54
10. 36
HVCB- 1
NO
HVCB- 2
GCB- 1
9. 0 5 k
V
0
GCB- 2
0
8/18/2019 Grounding design basis
http://slidepdf.com/reader/full/grounding-design-basis 15/26
ANNEXURE- B
MATERIAL AND SIZE DETAILS OF BELOW GRADE
AND ABOVE GRADE GROUNDING SYSTEM
8/18/2019 Grounding design basis
http://slidepdf.com/reader/full/grounding-design-basis 16/26
Doc. No. PE-DC-381-509-E002
Rev No. 0
19.02.13
Annexure-B:
SL. NO. TITLE MATERIAL
1 MAIN STATION GROUNDING
GRID
MS ROD
2 EARTH CONDUCTOR IN
CONCRETE FLOOR
GALVANISED MS
FLAT
3 ELECTRODES IN TEST PITS MS ROD
4 ELECTRODES FOR
LIGHTNING PROTECTION
DOWN CONDUCTORS
MS ROD
5 OTHER ELECTRODES MS ROD
SIZE
40 MM. DIA
75X10
40 MM. DIA
40 MM. DIA
Material and Size Details Of Below Grade & Above Grade Grounding System
Design Memorandum For Grounding System
2x660 MW IB TPS (UNIT-3 & 4), BANHARPALLI
40 MM. DIA
TABLE-1: BELOW GRADE GROUNDING SYSTEM - CONDUCTOR SIZES
2
02.01.14
8/18/2019 Grounding design basis
http://slidepdf.com/reader/full/grounding-design-basis 17/26
Doc. No. PE-DC-381-509-E002
Rev No. 0
19.02.13
Annexure-B:
Design Memorandum For Grounding System
2x660 MW IB TPS (UNIT-3 & 4), BANHARPALLI
SL.NO. TYPE OF EQUIPMENT SIZE (MM) MATERIAL NO. OF LEADS
1 RISERS 75 X 10 GALVANISED
STEEL FLAT
N.A.
2 SUB-MAT BURIED IN FLOOR
FINISH
75 X 10 GALVANISED
STEEL FLAT
N.A.
3 RUNWAY CONDUCTOR/ MAIN
EARTH LEAD ALONG COLUMNS
50 x 6 GALVANISED
STEEL FLAT
N.A.
4 11 kV/3.3 kV/ 415 V
SWITCHGEAR / MCC
75 X 10 GALVANISED
STEEL FLAT
TWO
5 SYSTEM NEUTRALS 75 X 10 GALVANISED
STEEL FLAT
TWO
6 415 V DISTRIBUTION BOARDS 50 x6 GALVANISED
STEEL FLAT
TWO
7 FUSE DISTRIBUTION BOARDS 50 X 6 GALVANISED
STEEL FLAT
TWO
8 11 kV & 3.3 kV MOTORS 50 X 6 GALVANISED
STEEL FLAT
TWO
9 415 V MOTORS : ABOVE 90 KW 50 X 6 GALVANISED
STEEL FLAT
TWO
Material and Size Details Of Below Grade & Above Grade Grounding System
TABLE-2: ABOVE GROUND EARTHING SYSTEM - CONDUCTOR SIZES
2
02.01.14
8/18/2019 Grounding design basis
http://slidepdf.com/reader/full/grounding-design-basis 18/26
Doc. No. PE-DC-381-509-E002
Rev No. 0
19.02.13
Annexure-B:
Design Memorandum For Grounding System
2x660 MW IB TPS (UNIT-3 & 4), BANHARPALLI
18 RAILS & METAL PARTS, FENCE 35 X 6 GALVANISED
STEEL FLAT
ONE
19 TRANSFORMER TANKS/
RADIATORS
75 X 10 GALVANISED
STEEL FLAT
TWO
20 GENERATOR ENCLOSURE 75 X 10 GALVANISED
STEEL FLAT
TWO
21 WELDING OUTLETS 3-PHASE
RECEPTACLES
35 X 6 GALVANISED
STEEL FLAT
TWO
22 LOCAL PANELS, LIGHTING
POLES
35 X 6 GALVANISED
STEEL FLAT
TWO
23 LIGHTING FIXTURES,SINGLE -
PHASE RECEPTACLES
16 SWG GI WIRE ONE
24 LIGHTING DISTRIBUTION
BOARDS
50 X 6 GALVANISED
STEEL FLAT
TWO
2
02.01.14
8/18/2019 Grounding design basis
http://slidepdf.com/reader/full/grounding-design-basis 19/26
1.0 TYPICAL SIZING CALCULATION FOR EARTHING CONDUCTORS OF PLANT AUXILIARIES
1.01
A=
I= 40000.00 Amperesc= . ec
A= 486.40 Square mm
Hence the Size chosen 65 x 10 mm is adequate
1.02 11 kV EQUIPMENT
A=
I= 40000.00 Amperesc= . ec
A= 486.40 Square mm
Hence the Size chosen 65 x 10 mm is adequate
1.03 11 KV/ 3.3 KV/ 415 V SWITCHGEAR , MCCS
A=
I= 50000.00 Amperesc= 1.00 Sec
A= 608.00 Square mm
Hence the Size chosen 65 x 10 mm is adequate
1.04 RISER, SUB-MAT
SAMPLE CALCULATION
NEUTRAL & ENCLOSURE EARTHING OF GENERATOR TRANSFORMER, STATION
TRANSFORMER, LT AUXILIARY TRANSFORMER, LT BUSDUCT, LT PCC/PMCC
( As per equation 33 of IEEE-80-2000 )
( As per equation 33 of IEEE-80-2000 )
( As per equation 33 of IEEE-80-2000 )
ct I 01216.0
ct I 01216.0
ct I 01216.0
8/18/2019 Grounding design basis
http://slidepdf.com/reader/full/grounding-design-basis 20/26
ANNEXURE- C
SOIL RESISTIVITY DATA ANALYSIS
8/18/2019 Grounding design basis
http://slidepdf.com/reader/full/grounding-design-basis 21/26
Doc. No. PE-DC-391-509-E002
Sl. No. AVERA GE SOIL RESISTIVITY (IN
OHM METER) AT 2 METER DEPTH
1 21.100
2 21.850
3 23.110
4 21.350
5 20.220
6 21.850
7 26.870
8 26.250
9 24.860
10 25.240
23.270
ERT 3
ERT 4
ERT 5
Net Average Resistivity (Ohm-m) at 2 M depth
ERT 6
ERT 7
ERT 8
ERT 9
ERT 10
Since the below grade earthing system is to be laid at a depth of 1M.
Soil resitivi ty value considered after taking suitable margin of over
100% = 50 (Ohm-m)
GROUNDING SYSTEM DESIGN MEMORANDUM Rev No. 01
2x660 MW IB TPS (UNIT-3 & 4), BANHARPALLI Date:19.02.13
Annexure-C: Soi l Resis tivi ty Data Analysis
ERT NO.
ERT 1
ERT 2
02.01.14
02
8/18/2019 Grounding design basis
http://slidepdf.com/reader/full/grounding-design-basis 22/26
ANNEXURE- D
SOIL RESISTIVITY TEST RESULTS
8/18/2019 Grounding design basis
http://slidepdf.com/reader/full/grounding-design-basis 23/26
-
,.,.-
51.
No.
ERT No.
Location
Spacing
in M tr.
1
2
3
4
2.00
I
3.00
-
9
9 00
Coo li
ng
Tower
4.00
,Ar
ea
6.00
8,00
2.00
-
3.00
10
10.00
Panel Bui lding
4.00
Area
6.0 0
8.0 0
Resistance
fn .(1
Mtr.
5
1.98
1 32
0.93
-
-
0 48
0 21
2 0i
1.82
1.45
0. 95
5
Resistivity In n crn.
6
2486 88
2486 88
2336 16
1808
64
1055 04
2524.56
3428. 88
3642 40
3579 60
1758 40
114
SWAYIN &
ASSOCJ.ATES
OPGC
j l r
8/18/2019 Grounding design basis
http://slidepdf.com/reader/full/grounding-design-basis 24/26
- -
•.
-
.
cr I
SI. No.
ERT N o.
Location
Spacing In Mtr Re
slstarice In
n
Mtr.
Re
sistivity
in
n
cm
I
1 2
3 \
4
5
6
I
I
2. 00
2.1 4 268 7 84
I
I
3 00
1 12
21 10 08
7
7.0.0
SWitchya rd
Area
4 00
. 0.76
1909
12
6
00
0. 32
1205 76
8..00
0.0 7
351 68
2 00 2.09
2625 04
I
.
3 00
1.03
1940 52
S
8 00
Sw
itc
h
yard
Area •
4 00
0.68
17
08 16
6 00
0.28
1055 04
8 00
0.06
301 44
113
SWAYIN .
ASSOCIATES
OPG.C
8/18/2019 Grounding design basis
http://slidepdf.com/reader/full/grounding-design-basis 25/26
I .
1
51.
No.
ERT No.
Location
Spacing .hi Mtl'.
1
2 3
4
2..00
3.00
TG Suilding
.
- '
4
4;
00
4.00
Are a
6.00
. 8.00
2.00·
3;0 0
5
5.00
Bo
ller Ar
ea
4.00
6. 00 .
8. 00 .
2.0 0
3.00
6
6.0
0 ·
Bo ner Area
4..00
6.00
8.00
-
112
'
,,-
,
,
. .
_
Resistance Ii ,
n
Nt-r;
t{esisthiity In n ·em.
. 5
I
(;
1.70
2135.20
0.85 · 1601 .40
0 30
753.60
0.07
263.76
0.00 0.00
1.61
2022. 16
-
0.79
1488.36
0. 29
728.48
0.04
J
150.72
0.00
0.00
1.74
2185 .44
0.98
1846.32
0.
47
1180.64
0.19 715.92
0.02
100.48
a·
r
. ;
.,
.
'
;
..,
,
'
'
OF GC
. ' - - - - ~ . - . - . --. . . . .
--
.
.
- : - . , . - ..,.__if.
8/18/2019 Grounding design basis
http://slidepdf.com/reader/full/grounding-design-basis 26/26
A
SWAY
IN
ASSOCIATES
OPG
51
No.
1
1
2
3
ERT No.
2
1..00
2.00
3.0
·0
Location
3
Transformer
Area
Transformer
Area
TG
Building
Area
I ~ U L I I Q ~ Q
5QIL
B r ; ~ 5 T I V I T Y
.-
Spacing in Mtr. Resistance in
n
Mtr
4
I
5
2 00
\
1.68
3.00 0.84
4.00
0.26
6.00
I
0.06
8.00
0.00
2.00
1.74
3.00
0.92
i
4.00
0.41
6.00
0.12
8.00
0. 00
2.00
1.8
4
3 .00
1. 13
4.00
0 .77
6.00
0 .4 1
8 00
0 .09
111
I
-
I
Resistivity
in
n
e
m
6
2110.08
15
82.56
6
53.12
22
6.08
0.00
21
85.44
1733.28
1029.
92
45.2.16
I
0 .00
231
1.0
4
2
128.9
2
1
93
4 .24
15
44.
88
452.16