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Figure 1: Substation Layout
structure connection operating handle
10m
Third Party Equipment
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Figure 2a: Soil resistivity data.
10 -1 10 0 10 1 10 2
Average Inter-Electrode Spacing (metres)
10 1
10 2
10 3
ApparentResistivity(Ohm-metres)
METRIC/LOGARITHMIC X AND Y
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Figure 2b: 3 layer, 2 layer and uniform soil resistivity curve.
10 -1 10 0 10 1 10 2
Average Inter-Electrode Spacing (metres)
10 1
10 2
10 3
Apparent Resistivity (Ohm-metres)
METRIC/LOGARITHMIC X AND Y
2 Layer Equivalent
Uniform Equivalent
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Figure 3: First draft electrode system.
Earth electrode 0.6m deep
3.6m earth rods
Fence earth rods
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-17.5 -10.5 -3.5 3.5 10.5 17.5
X AXIS (METERS)
-14
-7
0
7
14
21
Y A
XIS
(M
ET
ER
S)
Top View of Conductors
ALL ELECTRODES/NO LABELING [ID:Basic_Model_3.6M]
Figure 4: Basic computer model.
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-17.5 -10.5 -3.5 3.5 10.5 17.5
X AXIS (METERS)
-14
-7
0
7
14
21
Y A
XIS
(M
ET
ER
S)
Top View of Conductors
ALL ELECTRODES/NO LABELING [ID:Detail_Model]
Figure 5: Detailed computer model.
Figure 6: Touch voltage above earth grid.
-15 -5 5 15
X AXIS (METERS)
-15
-5
5
15
25
Y A
XIS
(M
ET
ER
S)
1 1
11
11
11
1
2
22
22
2
2
3
3 3
33
3
4
4 44
4
5
55 5
5
5
5
5
6
66
66
6
6
7
7
7
7
7
7
8
8
8
8
9
9
9
9
10
10
10
11
11
11
12
12
12
12
1313
13
14
14
14
15
15
16
16
17
17
18
18
1920
Touch Voltage Magnitude (Volts)
SINGLE-ELECTRODE/TOUCH VOLTAGES/USER DEFINED [ID:Detail_Model] LEGEND
MAXIMUM VALUE : 765.9462
MINIMUM VALUE : 44.12939
Level 20 ( 240.000 )
Level 19 ( 210.000 )
Level 18 ( 197.000 )
Level 17 ( 190.000 )
Level 16 ( 180.000 )
Level 15 ( 160.000 )
Level 14 ( 145.000 )
Level 13 ( 140.000 )
Level 12 ( 135.000 )
Level 11 ( 130.000 )
Level 10 ( 120.000 )
Level 9 ( 115.000 )
Level 8 ( 110.000 )
Level 7 ( 100.000 )
Level 6 ( 95.0000 )
Level 5 ( 90.0000 )
Level 4 ( 80.0000 )
Level 3 ( 70.0000 )
Level 2 ( 60.0000 )
Level 1 ( 50.0000 )
Figure 7: Surface potentials across earth grid.
-30 -15 0 15 30
X AXIS (METERS)
-30
-15
0
15
30
Y A
XIS
(M
ET
ER
S)
1
2
3
4
Potential Profile (% reference GPR)
MULTIPLE-ELECTRODE/SCALAR POTENTIALS [ID:Detail_Model] LEGEND
MAXIMUM VALUE : 95.18864
MINIMUM VALUE : 19.55564
Level 4 ( 85.2000 )
Level 3 ( 62.9000 )
Level 2 ( 50.0000 )
Level 1 ( 36.6000 ) 33kV Fault
11kV Fault
Figure 8: Surface potentials across final earth grid installation.
-30 -15 0 15 30
X AXIS (METERS)
-30
-15
0
15
30
Y A
XIS
(M
ET
ER
S)
1
2
3
4
4
Potential Profile (% reference GPR)
MULTIPLE-ELECTRODE/SCALAR POTENTIALS [ID:Detail_Model] LEGEND
MAXIMUM VALUE : 96.47353
MINIMUM VALUE : 24.88441
Level 4 ( 91.1000 )
Level 3 ( 75.0000 )
Level 2 ( 65.0000 )
Level 1 ( 53.0000 ) 33kV Fault
11kV Fault
Figure 9: Touch voltage above final earth grid installation.
-15 -5 5 15
X AXIS (METERS)
-15
-5
5
15
25Y
AX
IS (
ME
TE
RS)
1
1
1
11
11
2
22
2
2
2
3
33
3
3
3
3
4
4
4
5
5
5
6
6
66
789
Touch Voltage Magnitude (Volts)
SINGLE-ELECTRODE/TOUCH VOLTAGES/USER DEFINED [ID:Detail_Model_final] LEGEND
MAXIMUM VALUE : 456.8643
MINIMUM VALUE : 23.53455
Level 9 ( 110.000 )
Level 8 ( 100.000 )
Level 7 ( 90.0000 )
Level 6 ( 80.0000 )
Level 5 ( 70.0000 )
Level 4 ( 60.0000 )
Level 3 ( 50.0000 )
Level 2 ( 40.0000 )
Level 1 ( 30.0000 )
Figure 10: Step voltage above final earth grid installation.
Figure 11: Leakage current along vertical rod.
-16.5 -13.5 -10.5 -7.5 -4.5 -1.5
X AXIS (METERS)
13.5
10.5
7.5
4.5
1.5
-1.5Z
AX
IS (
ME
TE
RS)
5.7
1.4
0.91
4.5
1.0
1.1
1.2
1.3
1.3
1.4
1.5
1.5
4.5
4.6
4.7
4.7
4.8
4.9
5.0
5.0
5.2
5.3
5.5
5.8
6.7
465
Side View of Leakage Currents (Amps)
ALL ELECTRODES/LEAKAGE CURRENTS (SINGLE & MULTIPLE) [ID:Detail_Model]
Soil Surface
59Ωm, 1.1m
104Ωm, 4.6m
35Ωm, infinite.
1.4A
11.21A
71.2A
Figure 12: Surface potentials above final installation, in 3D.