![Page 1: Lightning Research at the University of Floridapes-spdc.org/sites/default/files/presentations/...The content of this presentation are for educational purpose. You are welcome to](https://reader034.vdocuments.mx/reader034/viewer/2022050513/5f9d4b9528247c31ef1741c7/html5/thumbnails/1.jpg)
Lightning Research at
the University of Florida
Shreeharsh Mallick
![Page 2: Lightning Research at the University of Floridapes-spdc.org/sites/default/files/presentations/...The content of this presentation are for educational purpose. You are welcome to](https://reader034.vdocuments.mx/reader034/viewer/2022050513/5f9d4b9528247c31ef1741c7/html5/thumbnails/2.jpg)
2
The content of this presentation are for educational purpose. You are welcome to
use these materials as long as you acknowledge the source.
![Page 3: Lightning Research at the University of Floridapes-spdc.org/sites/default/files/presentations/...The content of this presentation are for educational purpose. You are welcome to](https://reader034.vdocuments.mx/reader034/viewer/2022050513/5f9d4b9528247c31ef1741c7/html5/thumbnails/3.jpg)
3
The phenomenon of lightning occurs through a set of complex processes. In the subsequent slides, some of the details are abstracted in order to present the fundamental aspects of these processes in a simple way. To learn more about lightning, please refer to the books/papers in the reference slide (at the end) or contact • Dr. Vladimir A. Rakov (E-mail: [email protected]) • Dr. Martin A. Uman (Email: [email protected])
For information regarding UF Lightning Research Group, visit http://www.lightning.ece.ufl.edu
![Page 4: Lightning Research at the University of Floridapes-spdc.org/sites/default/files/presentations/...The content of this presentation are for educational purpose. You are welcome to](https://reader034.vdocuments.mx/reader034/viewer/2022050513/5f9d4b9528247c31ef1741c7/html5/thumbnails/4.jpg)
Introduction
![Page 5: Lightning Research at the University of Floridapes-spdc.org/sites/default/files/presentations/...The content of this presentation are for educational purpose. You are welcome to](https://reader034.vdocuments.mx/reader034/viewer/2022050513/5f9d4b9528247c31ef1741c7/html5/thumbnails/5.jpg)
Photograph by: Dustin Hill
What is
Lightning?
Lightning is the discharge of
atmospheric electricity
![Page 6: Lightning Research at the University of Floridapes-spdc.org/sites/default/files/presentations/...The content of this presentation are for educational purpose. You are welcome to](https://reader034.vdocuments.mx/reader034/viewer/2022050513/5f9d4b9528247c31ef1741c7/html5/thumbnails/6.jpg)
Earth
Thundercloud
+ + + + + + + + + + + + + + + + _ _ _ _ + + + _ _ _ _ + + _ _ _ _ + Thundercloud
+ + + _ _ _ _ _ _ _ _ _
Cloud-to-ground flash
Cloud-to-air flash
Cloud-to-cloud flash
(intercloud)
Cloud-to-cloud flash
(intracloud)
TLE or Transient Luminous Events (sprites, elves)
![Page 7: Lightning Research at the University of Floridapes-spdc.org/sites/default/files/presentations/...The content of this presentation are for educational purpose. You are welcome to](https://reader034.vdocuments.mx/reader034/viewer/2022050513/5f9d4b9528247c31ef1741c7/html5/thumbnails/7.jpg)
7
Downward
Negative
Downward
Positive
Upward
Negative
Upward
Positive
Depending on direction of propagation and polarity of charges (Adapted from Lightning Physics & Effects by V. A. Rakov & M. A. Uman)
Downward
Negative
(90% of
CG flash)
![Page 8: Lightning Research at the University of Floridapes-spdc.org/sites/default/files/presentations/...The content of this presentation are for educational purpose. You are welcome to](https://reader034.vdocuments.mx/reader034/viewer/2022050513/5f9d4b9528247c31ef1741c7/html5/thumbnails/8.jpg)
Objects on
Ground
Thundercloud
+ + + + + + +
_ _ _ _ _ _ _
_ _ _ _ _ _
+
Charges in Cloud
+ + + + + + + + + +
+ + + + + + + +
Image Charges
on Ground
Streamer
Stepped
Leader
Striking
Distance Upward
Leaders
Attachment
1st Return Stroke
Current
Ionized Air
Dart/Dart-Stepped
Leader
2nd Return Stroke
3rd Return Stroke
Negative
downward
natural
lightning
![Page 9: Lightning Research at the University of Floridapes-spdc.org/sites/default/files/presentations/...The content of this presentation are for educational purpose. You are welcome to](https://reader034.vdocuments.mx/reader034/viewer/2022050513/5f9d4b9528247c31ef1741c7/html5/thumbnails/9.jpg)
Natural lightning at Camp Blanding Photograph by: Dustin Hill
![Page 10: Lightning Research at the University of Floridapes-spdc.org/sites/default/files/presentations/...The content of this presentation are for educational purpose. You are welcome to](https://reader034.vdocuments.mx/reader034/viewer/2022050513/5f9d4b9528247c31ef1741c7/html5/thumbnails/10.jpg)
10
Still-camera
image Streak-camera image
Channel-base current
(Adapted from Lightning Physics & Effects by V. A. Rakov & M. A. Uman)
![Page 11: Lightning Research at the University of Floridapes-spdc.org/sites/default/files/presentations/...The content of this presentation are for educational purpose. You are welcome to](https://reader034.vdocuments.mx/reader034/viewer/2022050513/5f9d4b9528247c31ef1741c7/html5/thumbnails/11.jpg)
Various Steps of Lightning Discharge Process over Time
11 (Adapted from Lightning by M. A. Uman)
![Page 12: Lightning Research at the University of Floridapes-spdc.org/sites/default/files/presentations/...The content of this presentation are for educational purpose. You are welcome to](https://reader034.vdocuments.mx/reader034/viewer/2022050513/5f9d4b9528247c31ef1741c7/html5/thumbnails/12.jpg)
12
M-component
(Adapted from Lightning Physics & Effects by V. A. Rakov & M. A. Uman)
![Page 13: Lightning Research at the University of Floridapes-spdc.org/sites/default/files/presentations/...The content of this presentation are for educational purpose. You are welcome to](https://reader034.vdocuments.mx/reader034/viewer/2022050513/5f9d4b9528247c31ef1741c7/html5/thumbnails/13.jpg)
Negative Lightning for Cloud-to-Ground • Overall duration: 200-300 ms
• Peak current: 1st stroke = 30 kA
Sub. stroke = 10-15 kA
M-comp. = 100-200 A
• 10-90% current rise-time: 1st stroke = 5 µs
Sub. stroke = 0.3-0.6 µs
M-comp. = 300-500 µs
• Current duration to HPW-value on tail:
1st stroke = 70-80 µs
Sub. stroke = 30-40 µs
• Max. current rate of rise: 1st stroke = ≥10-20 kA/µs
Sub. stroke = 100 kA/µs
(Adapted from Lightning Physics & Effects by V. A. Rakov & M. A. Uman)
![Page 14: Lightning Research at the University of Floridapes-spdc.org/sites/default/files/presentations/...The content of this presentation are for educational purpose. You are welcome to](https://reader034.vdocuments.mx/reader034/viewer/2022050513/5f9d4b9528247c31ef1741c7/html5/thumbnails/14.jpg)
14
Parameters Units Sample size
% exceeding tabulated values
95% 50% 5%
Peak current (min. 2 kA)
1st strokes kA
101 14 30 80
Sub. Strokes 135 4.6 12 30
Max. dI/dt 1st strokes
kA/µs 92 5.5 12 32
Sub. Strokes 122 12 40 120
Front duration (2 kA to peak)
1st strokes µs
89 1.8 5.5 18
Sub. Strokes 118 0.22 1.1 4.5
Stroke duration (2 kA to HPW-value on tail)
1st strokes µs
90 30 75 200
Sub. Strokes 115 6.5 32 140
Flash duration 1st strokes
ms 94 0.15 13 1100
Sub. Strokes 39 31 180 900
Time interval between strokes
ms 133 7 33 150
Parameters of downward negative lightning based on channel-based current.
Adapted from Berger et al. (1975)
![Page 15: Lightning Research at the University of Floridapes-spdc.org/sites/default/files/presentations/...The content of this presentation are for educational purpose. You are welcome to](https://reader034.vdocuments.mx/reader034/viewer/2022050513/5f9d4b9528247c31ef1741c7/html5/thumbnails/15.jpg)
Ground-Based
Tall Object
Thundercloud
+ + + + + + +
_ _ _ _ _ _ _
_ _ _ _ _ _
+ Charges in Cloud
+ + + + + + + + + +
Image Charges
on Ground
Streamer
Upward
Positive
Leader
Initial
Continuous
Current
Subsequent
Return Stroke
Ionized Air Dart/Dart-Stepped
Leader
Upward
lightning
![Page 16: Lightning Research at the University of Floridapes-spdc.org/sites/default/files/presentations/...The content of this presentation are for educational purpose. You are welcome to](https://reader034.vdocuments.mx/reader034/viewer/2022050513/5f9d4b9528247c31ef1741c7/html5/thumbnails/16.jpg)
Lightning striking Burj Khalifa in Dubai
(unknown source)
![Page 17: Lightning Research at the University of Floridapes-spdc.org/sites/default/files/presentations/...The content of this presentation are for educational purpose. You are welcome to](https://reader034.vdocuments.mx/reader034/viewer/2022050513/5f9d4b9528247c31ef1741c7/html5/thumbnails/17.jpg)
17
Still-camera
image Streak-camera image
Channel-base current
Note initial continuous current in place of first return stroke
(Adapted from Lightning Physics & Effects by V. A. Rakov & M. A. Uman)
![Page 18: Lightning Research at the University of Floridapes-spdc.org/sites/default/files/presentations/...The content of this presentation are for educational purpose. You are welcome to](https://reader034.vdocuments.mx/reader034/viewer/2022050513/5f9d4b9528247c31ef1741c7/html5/thumbnails/18.jpg)
Rocket
Launcher
Thundercloud _ _ _ _ _ _ _
_ _ _ _ _ _
+
Charges in Cloud
+ + + + + + + + + +
Image Charges
on Ground
Wire connected
to Ground
Streamer
Upward
Positive
Leader
Natural Channel
Exploded Wire
Initial
Continuous
Current Ionized Air
Dart/Dart-Stepped
Leader
Subsequent
Return Stroke
Triggered
lightning
using rocket-
and-wire
technique
![Page 19: Lightning Research at the University of Floridapes-spdc.org/sites/default/files/presentations/...The content of this presentation are for educational purpose. You are welcome to](https://reader034.vdocuments.mx/reader034/viewer/2022050513/5f9d4b9528247c31ef1741c7/html5/thumbnails/19.jpg)
Rocket Triggered Lightning at Camp Blanding
![Page 20: Lightning Research at the University of Floridapes-spdc.org/sites/default/files/presentations/...The content of this presentation are for educational purpose. You are welcome to](https://reader034.vdocuments.mx/reader034/viewer/2022050513/5f9d4b9528247c31ef1741c7/html5/thumbnails/20.jpg)
20
Subsequent strokes in triggered lightning are
similar to those in natural lightning
(Adapted from Lightning Physics & Effects by V. A. Rakov & M. A. Uman)
![Page 21: Lightning Research at the University of Floridapes-spdc.org/sites/default/files/presentations/...The content of this presentation are for educational purpose. You are welcome to](https://reader034.vdocuments.mx/reader034/viewer/2022050513/5f9d4b9528247c31ef1741c7/html5/thumbnails/21.jpg)
Interceptor Rocket
Launcher
Thundercloud _ _ _ _ _ _ _
_ _ _ _ _ _
+
Charges in Cloud
+ + + + + + + + + +
Image Charges
on Ground
Wire not
connected to
ground
Streamers
Leaders
Current
Return Stroke
Altitude
triggered
lightning
![Page 22: Lightning Research at the University of Floridapes-spdc.org/sites/default/files/presentations/...The content of this presentation are for educational purpose. You are welcome to](https://reader034.vdocuments.mx/reader034/viewer/2022050513/5f9d4b9528247c31ef1741c7/html5/thumbnails/22.jpg)
22
Lightning
strikes plane
while take off in
Japan
(unknown
source).
(classical
example of
altitude
triggered
lightning)
![Page 23: Lightning Research at the University of Floridapes-spdc.org/sites/default/files/presentations/...The content of this presentation are for educational purpose. You are welcome to](https://reader034.vdocuments.mx/reader034/viewer/2022050513/5f9d4b9528247c31ef1741c7/html5/thumbnails/23.jpg)
23
UF Lightning Research
Group
![Page 24: Lightning Research at the University of Floridapes-spdc.org/sites/default/files/presentations/...The content of this presentation are for educational purpose. You are welcome to](https://reader034.vdocuments.mx/reader034/viewer/2022050513/5f9d4b9528247c31ef1741c7/html5/thumbnails/24.jpg)
Facilities
• The Lightning Center for Lightning Research
and Testing (ICLRT) at Camp Blanding, FL
– Rocket-Triggered Lightning Experiments
• The Lightning Observatory in Gainesville, FL
(45 km from Camp Blanding)
• Starke Site (3 km from Camp Blanding)
• The Lightning Research Laboratory
24
![Page 25: Lightning Research at the University of Floridapes-spdc.org/sites/default/files/presentations/...The content of this presentation are for educational purpose. You are welcome to](https://reader034.vdocuments.mx/reader034/viewer/2022050513/5f9d4b9528247c31ef1741c7/html5/thumbnails/25.jpg)
Activities
• Studying the various physical
processes in natural and rocket-
triggered lightning
– Current shunts/Pearson coil
– Electric and Magnetic field antennas
– X-Ray detectors
– HF and VHF systems
– Optical equipments
25
![Page 26: Lightning Research at the University of Floridapes-spdc.org/sites/default/files/presentations/...The content of this presentation are for educational purpose. You are welcome to](https://reader034.vdocuments.mx/reader034/viewer/2022050513/5f9d4b9528247c31ef1741c7/html5/thumbnails/26.jpg)
ICLRT at Camp Blanding, Florida
26 (Adapted from Lightning Physics & Effects by V. A. Rakov & M. A. Uman)
![Page 27: Lightning Research at the University of Floridapes-spdc.org/sites/default/files/presentations/...The content of this presentation are for educational purpose. You are welcome to](https://reader034.vdocuments.mx/reader034/viewer/2022050513/5f9d4b9528247c31ef1741c7/html5/thumbnails/27.jpg)
Rocket Triggered Lightning
(Click on the photograph to start video)
![Page 28: Lightning Research at the University of Floridapes-spdc.org/sites/default/files/presentations/...The content of this presentation are for educational purpose. You are welcome to](https://reader034.vdocuments.mx/reader034/viewer/2022050513/5f9d4b9528247c31ef1741c7/html5/thumbnails/28.jpg)
Rocket Triggered Lightning
(Click on the photograph to start video)
![Page 29: Lightning Research at the University of Floridapes-spdc.org/sites/default/files/presentations/...The content of this presentation are for educational purpose. You are welcome to](https://reader034.vdocuments.mx/reader034/viewer/2022050513/5f9d4b9528247c31ef1741c7/html5/thumbnails/29.jpg)
Rocket Triggered Lightning
(Click on the photograph to start video)
![Page 30: Lightning Research at the University of Floridapes-spdc.org/sites/default/files/presentations/...The content of this presentation are for educational purpose. You are welcome to](https://reader034.vdocuments.mx/reader034/viewer/2022050513/5f9d4b9528247c31ef1741c7/html5/thumbnails/30.jpg)
30
LOG is located 45 km from CB. Starke site, which is located 3 km
from CB, is not shown on the map.
![Page 31: Lightning Research at the University of Floridapes-spdc.org/sites/default/files/presentations/...The content of this presentation are for educational purpose. You are welcome to](https://reader034.vdocuments.mx/reader034/viewer/2022050513/5f9d4b9528247c31ef1741c7/html5/thumbnails/31.jpg)
Single-station expt. (Natural lightning around Gainesville)
Lightning Observatory in Gainesville
X-ray detector
dE/dt antenna
E-field antenna
Glass Cupola
![Page 32: Lightning Research at the University of Floridapes-spdc.org/sites/default/files/presentations/...The content of this presentation are for educational purpose. You are welcome to](https://reader034.vdocuments.mx/reader034/viewer/2022050513/5f9d4b9528247c31ef1741c7/html5/thumbnails/32.jpg)
Multi-station expt. (RTL at CB; far-field measurements at 45 km)
Lightning Observatory in Gainesville
![Page 33: Lightning Research at the University of Floridapes-spdc.org/sites/default/files/presentations/...The content of this presentation are for educational purpose. You are welcome to](https://reader034.vdocuments.mx/reader034/viewer/2022050513/5f9d4b9528247c31ef1741c7/html5/thumbnails/33.jpg)
Flash UF 09-25
33
Near and far field measurement
![Page 34: Lightning Research at the University of Floridapes-spdc.org/sites/default/files/presentations/...The content of this presentation are for educational purpose. You are welcome to](https://reader034.vdocuments.mx/reader034/viewer/2022050513/5f9d4b9528247c31ef1741c7/html5/thumbnails/34.jpg)
Multi-station expt. (RTL at CB; far-field measurements at 3 km)
Single-station expt. (Natural lightning around Starke)
Starke Site
![Page 35: Lightning Research at the University of Floridapes-spdc.org/sites/default/files/presentations/...The content of this presentation are for educational purpose. You are welcome to](https://reader034.vdocuments.mx/reader034/viewer/2022050513/5f9d4b9528247c31ef1741c7/html5/thumbnails/35.jpg)
Study on distribution line done at Camp Blanding
![Page 36: Lightning Research at the University of Floridapes-spdc.org/sites/default/files/presentations/...The content of this presentation are for educational purpose. You are welcome to](https://reader034.vdocuments.mx/reader034/viewer/2022050513/5f9d4b9528247c31ef1741c7/html5/thumbnails/36.jpg)
Study on underground cable done at Camp Blanding
Fulgurite
![Page 37: Lightning Research at the University of Floridapes-spdc.org/sites/default/files/presentations/...The content of this presentation are for educational purpose. You are welcome to](https://reader034.vdocuments.mx/reader034/viewer/2022050513/5f9d4b9528247c31ef1741c7/html5/thumbnails/37.jpg)
Study on underground cable done at Camp Blanding
![Page 38: Lightning Research at the University of Floridapes-spdc.org/sites/default/files/presentations/...The content of this presentation are for educational purpose. You are welcome to](https://reader034.vdocuments.mx/reader034/viewer/2022050513/5f9d4b9528247c31ef1741c7/html5/thumbnails/38.jpg)
Study on residential house done at Camp Blanding
(Click on the photograph to start video)
![Page 39: Lightning Research at the University of Floridapes-spdc.org/sites/default/files/presentations/...The content of this presentation are for educational purpose. You are welcome to](https://reader034.vdocuments.mx/reader034/viewer/2022050513/5f9d4b9528247c31ef1741c7/html5/thumbnails/39.jpg)
Case Study
Triggered-Lightning Testing of Lightning Protective System
of a Residential Building
(Triggered-Lightning Testing of the Protective System of a Residential Building: 2004 and 2005 Results, B.A. DeCarlo, V.A. Rakov, J. Jerauld, G.H. Schnetzer, J. Schoene, M.A. Uman, K.J. Rambo, V. Kodali, D.M. Jordan, G. Maxwell, S. Humeniuk, and M. Morgan, ICLP 2006)
![Page 40: Lightning Research at the University of Floridapes-spdc.org/sites/default/files/presentations/...The content of this presentation are for educational purpose. You are welcome to](https://reader034.vdocuments.mx/reader034/viewer/2022050513/5f9d4b9528247c31ef1741c7/html5/thumbnails/40.jpg)
Test House
Lead
conductor
Test RunwayTest
3-Phase
Distribution
Line
IS1
600 V
Underground
Cable
Launch
Control
Tower
Launcher
Office
N
Experimental set-up
![Page 41: Lightning Research at the University of Floridapes-spdc.org/sites/default/files/presentations/...The content of this presentation are for educational purpose. You are welcome to](https://reader034.vdocuments.mx/reader034/viewer/2022050513/5f9d4b9528247c31ef1741c7/html5/thumbnails/41.jpg)
North Instrumentation boxNorth Instrumentation box
The test house at the ICLRT whose LPS was subjected to direct lightning strikes in 2004 and 2005. Approximate dimensions of the house are 10 x 7 x 6.5 m3. Photo from 2005.
![Page 42: Lightning Research at the University of Floridapes-spdc.org/sites/default/files/presentations/...The content of this presentation are for educational purpose. You are welcome to](https://reader034.vdocuments.mx/reader034/viewer/2022050513/5f9d4b9528247c31ef1741c7/html5/thumbnails/42.jpg)
Experimental set-up (2004)
Ground
Level
Lightning current
injection point
To electrical
circuit neutral
Air
terminal
N
B
A
D
C
3.8 m
9.9 m
4.6 m
3.4 m 3 m 6.1 m
Diagram of the LPS of the test house in 2004. All conductors below the plane labeled “Ground Level” are buried (in direct contact with earth). Note: Return stroke current only was injected in 2004.
![Page 43: Lightning Research at the University of Floridapes-spdc.org/sites/default/files/presentations/...The content of this presentation are for educational purpose. You are welcome to](https://reader034.vdocuments.mx/reader034/viewer/2022050513/5f9d4b9528247c31ef1741c7/html5/thumbnails/43.jpg)
Electrical diagram of test system configuration for 2004. Currents A, B, C, D, and K were measured at the test house, and current G was measured at IS1, 50-m away.
Experimental set-up (2004)
336 Ω 468 Ω 668 Ω 69 Ω
50 Ω50 Ω
600-V Cable
A B C
6 Ω
4 Ω
D
K
Buried
conductor
G
Watt-hour
meter
SPDs
![Page 44: Lightning Research at the University of Floridapes-spdc.org/sites/default/files/presentations/...The content of this presentation are for educational purpose. You are welcome to](https://reader034.vdocuments.mx/reader034/viewer/2022050513/5f9d4b9528247c31ef1741c7/html5/thumbnails/44.jpg)
Injected
Point A
Point B
(a)
Return-stroke currents for stroke 0401-3, displayed on a 10 µs time scale. (a) injected current and currents at points A, B, C, D, and K; (b) currents for flash 0401-7.
Current division results (2004)
Point C Point D
Point K
(b)
336 Ω 468 Ω 668 Ω 69 Ω
50 Ω50 Ω
600-V Cable
A B C
6 Ω
4 Ω
D
K
Buried
conductor
G
Watt-hour
meter
SPDs
![Page 45: Lightning Research at the University of Floridapes-spdc.org/sites/default/files/presentations/...The content of this presentation are for educational purpose. You are welcome to](https://reader034.vdocuments.mx/reader034/viewer/2022050513/5f9d4b9528247c31ef1741c7/html5/thumbnails/45.jpg)
Diagram of the LPS of the test house in 2005. All conductors below the plane labeled “Ground Level” are buried (in direct contact with earth). Note: Both initial-stage and return-stroke currents were injected in 2005.
Experimental set-up (2005)
3.8 m
9.9 m
4.6 m
6.8 m
3 m
3.4 m
Ground
Level
Lightning current
injection point
To electrical
circuit neutral
Air
terminal
N
B
B1
A1
A
D
![Page 46: Lightning Research at the University of Floridapes-spdc.org/sites/default/files/presentations/...The content of this presentation are for educational purpose. You are welcome to](https://reader034.vdocuments.mx/reader034/viewer/2022050513/5f9d4b9528247c31ef1741c7/html5/thumbnails/46.jpg)
Experimental set-up (2005)
Electrical diagram of test system configuration for 2005. Currents A, A1, B, B1, and D were measured at the test house, and Current G was measured at IS1, 50 m away.
Buried loop conductor
442 Ω 488 Ω 518 Ω 524 Ω 636 Ω 69 Ω
50 Ω50 Ω
600-V Cable
A B1A1 B D G
Watt-hour
meter
![Page 47: Lightning Research at the University of Floridapes-spdc.org/sites/default/files/presentations/...The content of this presentation are for educational purpose. You are welcome to](https://reader034.vdocuments.mx/reader034/viewer/2022050513/5f9d4b9528247c31ef1741c7/html5/thumbnails/47.jpg)
(a) Return stroke currents in four downleads (A, A1, B, and B1) , (b) The sum of the four downlead currents (A, A1, B, and B1) vs. the injected current
waveform displayed on a 110 µs time scale for stroke 0521-1.
Current division results (2005)
0 20 40 60 80 100-3
-2
-1
0
Time, s
Cu
rren
t, k
A0521-1
Downlead A
Downlead A1
Downlead B
Downlead B1
0 20 40 60 80 100-8
-6
-4
-2
0
Time, s
Cu
rren
t, k
A
0521-1
Injected Current
Sum of 4 Downleads
(a)
(b)
![Page 48: Lightning Research at the University of Floridapes-spdc.org/sites/default/files/presentations/...The content of this presentation are for educational purpose. You are welcome to](https://reader034.vdocuments.mx/reader034/viewer/2022050513/5f9d4b9528247c31ef1741c7/html5/thumbnails/48.jpg)
(a) Injected current versus the difference between the sum of the four downlead currents and current D, labeled (Sum – D). The (Sum – D) waveform is scaled so that its peak is equal to that of the injected current and represents the current going to the grounding system (local) of the test house. (b) Current D versus current G.
Current division results (2005)
(a)
(b)
0 20 40 60 80 100-10
-5
0
Time, s
Cu
rren
t, k
A0521-1
Injected Current
(Sum - D), scaled
0 20 40 60 80 100-6
-4
-2
0
Time, s
Cu
rren
t, k
A
0521-1
Current D
Current G
![Page 49: Lightning Research at the University of Floridapes-spdc.org/sites/default/files/presentations/...The content of this presentation are for educational purpose. You are welcome to](https://reader034.vdocuments.mx/reader034/viewer/2022050513/5f9d4b9528247c31ef1741c7/html5/thumbnails/49.jpg)
Current division results, 2004 vs. 2005
Peak value of current D (current to electrical circuit neutral) vs. injected peak current for return strokes in flashes triggered in 2004 and 2005.
Over 80% of the injected peak current was observed to enter the electrical circuit neutral in similar 1997 tests at the ICLRT (Rakov et al., 2002).
Characteristics Injected current,
kA
Current D, kA Current D relative
to Injected current,
%
2004 2005 2004 2005 2004 2005
Minimum 3.6 6.8 0.8 4.4 16 51
Maximum 17.8 34.4 3.4 8.5 28 72
Arithmetic Mean 9.4 14.4 2.1 6.6 22 59
Standard
Deviation
4.1 8.8 0.9 1.8 3.6 8.5
Geometric Mean 4.7 12.7 1.9 6.1 22 58
Sample Size 11 8 11 7 11 7
![Page 50: Lightning Research at the University of Floridapes-spdc.org/sites/default/files/presentations/...The content of this presentation are for educational purpose. You are welcome to](https://reader034.vdocuments.mx/reader034/viewer/2022050513/5f9d4b9528247c31ef1741c7/html5/thumbnails/50.jpg)
Damage to the system
Damage to the insulation of the 600-V cable, (a) puncture of the insulation of one conductor of the 600-V cable, (b) damage to all three conductors of the cable.
y
4 mm Adjacent damage
(b) (a)
![Page 51: Lightning Research at the University of Floridapes-spdc.org/sites/default/files/presentations/...The content of this presentation are for educational purpose. You are welcome to](https://reader034.vdocuments.mx/reader034/viewer/2022050513/5f9d4b9528247c31ef1741c7/html5/thumbnails/51.jpg)
Bar charts of peak current of injected (Inj.) current, currents in ground rod A, ground rod A1 (2005), ground rod B, ground rod B1 (2005), ground rod C (2004), and current D for events LSA-0401-1 and LSA-0521-1.
Current division results (2004 vs. 2005)
2005
0521-1
Inj. A A1 B B1 D
Peak C
urr
ent,
kA
0
2
4
6
8
Ground
Level
Lightning current
injection point
To
electrical
circuit
neutral
Air
terminal
N
B
B1
A1
A
D
2004
0401-1
Inj. A B C D
Pe
ak c
urr
en
t, k
A
0
2
4
6
8
10
12
14
16
Ground
Level
Lightning current
injection point
To electrical
circuit neutral
Air
terminal
N
B
A
D
C
![Page 52: Lightning Research at the University of Floridapes-spdc.org/sites/default/files/presentations/...The content of this presentation are for educational purpose. You are welcome to](https://reader034.vdocuments.mx/reader034/viewer/2022050513/5f9d4b9528247c31ef1741c7/html5/thumbnails/52.jpg)
Current division results (2004 vs. 2005)
Bar charts of half-peak width of injected (Inj.) current, currents in ground rod A, ground rod A1 (2005), ground rod B, ground rod B1 (2005), ground rod C (2004), and current D for events 0401-1 and 0521-1.
3
Inj. A B C D
HPW
, µs
0
10
20
30
40
50
60
70
80
2004
0401-1
Ground
Level
Lightning current
injection point
To electrical
circuit neutral
Air
terminal
N
B
A
D
C
0521-1
Inj. A A1 B B1 D
HPW
, µ
s
0
5
10
15
20
25
30
35
2005 Ground
Level
Lightning current
injection point
To
electrical
circuit
neutral
Air
terminal
N
B
B1
A1
A
D
![Page 53: Lightning Research at the University of Floridapes-spdc.org/sites/default/files/presentations/...The content of this presentation are for educational purpose. You are welcome to](https://reader034.vdocuments.mx/reader034/viewer/2022050513/5f9d4b9528247c31ef1741c7/html5/thumbnails/53.jpg)
• Current entering the electrical circuit neutral in percent of the
injected current:
1997 – >80%
2004 – 22%
2005 – 59% better grounding at the test house than in 1997
Summary • The primary objective was to examine current division between
local (at the test house) and remote grounding systems
• Overall, configuration tested in 2004 (RS only; SPDs installed)
performed better than the configuration tested in 2005 (IS + RS;
SPDs disconnected)
• In absence of SPDs in 2005, the watt-hour meter incurred damage,
similar to the no-SPD configuration tested in 1997 (Rakov et al.,
2002)
Roughly a factor of two to three larger current in 2005 than in 2004 was forced to search its way to remote ground
![Page 54: Lightning Research at the University of Floridapes-spdc.org/sites/default/files/presentations/...The content of this presentation are for educational purpose. You are welcome to](https://reader034.vdocuments.mx/reader034/viewer/2022050513/5f9d4b9528247c31ef1741c7/html5/thumbnails/54.jpg)
54
For information regarding UF Lightning Research Group, visit
http://www.lightning.ece.ufl.edu
QUESTIONS?
![Page 55: Lightning Research at the University of Floridapes-spdc.org/sites/default/files/presentations/...The content of this presentation are for educational purpose. You are welcome to](https://reader034.vdocuments.mx/reader034/viewer/2022050513/5f9d4b9528247c31ef1741c7/html5/thumbnails/55.jpg)
References • Lightning Physics and Effects, V. A. Rakov and M.
A. Uman, Cambridge University Press, 2003
• Lightning, M. A. Uman, Dover Publication, 1969
• Triggered-Lightning Testing of the Protective System of a Residential Building: 2004 and 2005 Results, B.A. DeCarlo, V.A. Rakov, J. Jerauld, G.H. Schnetzer, J. Schoene, M.A. Uman, K.J. Rambo, V. Kodali, D.M. Jordan, G. Maxwell, S. Humeniuk, and M. Morgan, ICLP 2006
55
![Page 56: Lightning Research at the University of Floridapes-spdc.org/sites/default/files/presentations/...The content of this presentation are for educational purpose. You are welcome to](https://reader034.vdocuments.mx/reader034/viewer/2022050513/5f9d4b9528247c31ef1741c7/html5/thumbnails/56.jpg)
Photograph by: Dustin Hill