A STUDY ON THE EARLY STREAMER EMISSION (ESE) …eprints.utm.my/id/eprint/5774/1/NguEngEngMFKE2004.pdfSistem penangkap kilat Early Streamer Emission (ESE) adalah merupakan teknik agak

A STUDY ON THE EARLY STREAMER EMISSION (ESE) LIGHTNING

PROTECTION SYSTEM

NGU ENG ENG

A thesis submitted in fulfilment of the

requirements for the award of the degree of

Master of Engineering (Electrical)

Faculty of Electrical Engineering

Universiti Teknologi Malaysia

OCTOBER 2004

iii

To my beloved father, mother and brothers

iv

ACKNOWLEDGEMENT

In carrying out this study, the author would like to acknowledge the

assistance, support and guidance given by individuals and organizations from both

inside and outside the university. First and the most importantly, I wish to express

my sincere gratitude to my project supervisor, Professor Dr. Ahmad Bin Darus, for

his encouragement, professional guidance, endless patience and assistance. Without

his continued support and constructive ideas, this thesis would not have come to the

fruition. I am also very thankful to Professor Dr. Tharek Abd. Rahman, the Director

of the Wireless Communication Centre (WCC), Faculty of Electrical Engineering,

Universiti Teknologi Malaysia (UTM), Skudai Johor for his assistance in allowing

the lightning protection system to be set-up at the centre. I am also indebted to UTM

for funding my Masters study for two years.

The cooperation given by Mun Hean (Msia) Sdn Bhd in giving a complete

unit of the Early Streamer Emission (ESE) Lightning Protection (LP) to be installed

in UTM is gratefully acknowledged. I would also like to express my appreciation to

TNB Research Sdn Bhd in Bangi for providing me very useful information on the

lightning activities in the area covered by this study. Overseas researchers also

deserve special thanks for their assistance in supplying the relevant literatures and

their findings.

Finally, I would like to gratefully acknowledge the helpful comments and

contributions of my fellow postgraduate students who had given me moral support.

My sincere appreciation also extends to staff of Institute of High Voltage and High

Current (IVAT), my family and who have provided assistance at various occasions.

Their views and tips are useful indeed. Unfortunately, it is not possible to list all of

them in this limited space.

v

ABSTRACT

Early Streamer Emission (ESE) Lightning Protection (LP) system is a

relatively new approach in solving the perennial problem of lightning damage, which

has been associated with the use of Franklin Rod (FR). Based on theoretical

consideration and some previous work by several researchers, the ESE is believed to

be providing more effective protection against lightning than would a FR system.

However, the scientific and technical basis to support the belief of this improved

system is still not concrete enough and this then inevitably leads to the efficacy of

these technologies still remain opened for further study and improvement. The new

system is equipped with a special device that is used to extend the effective range of

protection over that of the FR. In this work, results have been obtained from the

simulated testing carried out in the laboratory and also from field monitoring of real

FR and ESE system installed in the university campus. Visits to several sites, which

employ these systems, have enabled physical observation of the after effects of

lightning be recorded for analyses. The results show that slightly rounded air

terminal, which is typical of ESE system offer better interception ability than that of

sharp terminals, which is the typical FR design. It is also shown that ionizing the air

around the tip of the terminals can enhance its effectiveness. This conclusion is

substantiated by field observation obtained from the installed systems where the ESE

system has been found to intercept more lightning strikes than that by the FR.

vi

ABSTRAK

Sistem penangkap kilat Early Streamer Emission (ESE) adalah merupakan

teknik agak baru yang digunakan dalam menyelesaikan masalah kerosakan akibat

sambaran kilat yang berlaku dalam penggunaan sistem penangkap kilat Franklin Rod

(FR). Berdasarkan kepada kajian teoritikal dan juga hasil kerja beberapa penylidik

adalah dipercayai bahawa ESE berkemampuan memberi perlindungan kilat yang

lebih efektif daripada FR. Sistem ESE ini dilengkapi dengan satu peranti khusus

yang berfungsi untuk melebarkan jangkauan berkesan perlindungan berbanding

dengan yang diberikan oleh sistem FR. Dalam kajian ini, keputusan telah diperolehi

daripada kerja-kerja simulasi di makmal dan daripada pemantauan luar terhadap

sistem ESE dan FR yang dipasang pada bangunan dalam kampus. Lawatan ke

beberapa tempat dan bangunan di luar kampus yang menggunakan sistem-sistem

perlindungan kilat ini membolehkan cerapan fizikal kesan daripada masalah

sembaran kilat direkod untuk analisis. Daripada kajian-kajian ini, didapati bahawa

pangkal atau bahagian hujung penagkap kilat yang lebih berbentuk bulat (iaitu

bentuk yang digunakan dalam ESE) memberikan kemampuan memintas sambaran

kilat yang lebih baik berbanding dengan pangkal yang tajam. Juga didapati bahawa

kesan proses pengionan di sekitar pangkal penangkap kilat boleh meningkatkan lagi

keberkesanan system perlindungan kilat itu. Kesimpulan ini disokong oleh dapatan

daripada pemantuan luar yang mana menunjukkan bahawa system perlindungan ESE

memintas lebih banyak sambaran kilat daripada system FR di tempat kajian.

vii

TABLE OF CONTENTS

CHAPTER TITLE PAGE

COVER PAGE i

DECLARATION ii

DEDICATION iii

ACKNOWLEDGEMENT iv

ABSTRACT v

ABSTRAK vi

TABLE OF CONTENTS vii

LIST OF TABLES xi

LIST OF FIGURES xiii

LIST OF ABBREVIATION xx

LIST OF SYMBOLS xxii

LIST OF APPENDIX xxv

1 INTRODUCTION 1

1.1 Overview on the Principle of Early Streamer Initiation

Mechanism 1

1.2 Review of Previous Works 4

1.2.1 Outcomes that Indicate the Relative

Superiority of the ESE Lightning Protection

System 5

1.2.2 Observations which Do Not Indicate

viii

Significant Advantage of the ESE Lightning

Protection System 8

viii

1.3 Objectives of the Study 10

1.4 Contributions of the Project 11

1.5 Scope of Study 12

1.6 Summary of Thesis Chapters 13 2 Literature Review 14

2.1 Lightning Phenomena 14

2.1.1 Lightning Discharge Mechanism 15

2.1.2 Types of Risk Related to Lightning Strike 17

2.1.3 Effects from Lightning Strike 20

2.2 Introduction to Lightning Protection Systems 23

2.2.1 Categories of Lightning Protection Systems 23

2.2.2 Classification of Lightning Protection

Technique 25

2.2.3 Types of Lightning Protection Systems:

Conventional and Non-Conventional 26

2.2.4 The Pulsar 29

2.2.4.1 Operating Principle of the Pulsar 31

2.2.5 The Prevectron 4 33

2.2.5.1 Operating Principle of the

Prevectron 4 34

2.3 Important Factors in Assessing the Air

Terminal Performance 35

2.3.1 Corona Effect 35

2.3.2 Electric Field 39

3 METHODOLOGY 43

3.1 Setting Up of a Lightning Detection System

at UTM 43

3.2 Laboratory Testing Using Simulated System 47

3.2.1 Experiment Apparatus 48

ix

3.2.2 General Test Set Up 52

3.2.3 General Test Procedures 53

3.2.3.1 Test to Study the Effect of Air

Terminal Profile 54

3.2.3.2 Study on the Effect of Terminal

Ionization Condition 58

3.2.3.3 Study on the Comparative

Performance of Conditioning and

Simple Rods 61

3.3 Visits to Installation where either One or Both of

the FR and ESE Systems are used 62

4 RESULTS AND DISCUSSIONS 64

4.1 Results Obtained from the Lightning Detection

System Installed in UTM 64

4.2 Results Obtained from the Experiment on Simulated

Test System 67

4.2.1 Effect of Air Terminal Geometry Test 68

4.2.2 Simulation of Terminal Ionization Condition 72

4.2.3 Comparative Performance of Conditioning

and Simple Rod 77

4.3 Observation Obtained from the Visit to Installation

with FR and ESE Systems 81

4.3.1 Johor Matriculation College (KMJ),

Tangkak, Johor 81

4.3.1.1 Result of Observation at KMJ 84

4.3.2 Golf Resort, Kota Tinggi, Johor 86

4.3.2.1 Result of Observation at the

Golf Resort 89

4.4 Discussions 90

4.4.1 Analyzing Laboratory and Filed Data 90

4.4.1.1 Propagation Speed of the Upward

x

Streamer, υ+ and Downward

Leader, υ- 90

4.4.1.2 Effect of Air Terminal Geometry 94

4.4.1.3 Local Field 96

4.4.2 Analysis of Data Obtained from the

Lightning Detection System and Field

Observation 99

5 CONCLUSIONS 101

6 SUGGESTIONS 104

REFERENCES 106 APPENDICES 113

xi

LIST OF TABLES

TABLE NO TITLE PAGE 2.1 Conditions for the ambient field (Eo) for stable

propagation of the upward streamer [30] 40 3.1 Description of electrodes used in the test 55 4.1 Summarized result of the parameters tested in the first

series of the test 68

4.2 Summarized result of the parameters tested in the second series of the test 68

4.3 Total percentage of discharge terminated at each rod for 152 voltage applications. 71

4.4 Data obtained from each sample of the test 72 4.5 Results obtained from the curve fitting technique 74 4.6 Simplified results of measured parameters 78 4.7 The relation between the conditioning duration and

the percentage of the number of discharge terminated at the conditioning rod 81

E.1 Radius of Protection for Pulsar 30, Pulsar 45 and Pulsar 60 125

F.1 Radius of reinforced protection (level 1) for Prevectron, INDELEC 126

F.2 Radius of intermediate protection (level 2) for Prevectron, INDELEC 126

F.3 Four different models of Prevectron 4 with their specifications 127

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I.2 First series of up-and-down test 134 I.3 Second series of up-and-down test 134 I.4 Third series of up-and-down test 135 L.4 Data obtained in the first series of the geometrical

effect test 142

L.8 Data obtained in the second series of the geometrical effect test (60 trials) 144

L.9 Tb/d for CLR obtained in the simulation of ionization condition test 145

L.13 Tb/d for NCLR obtained in the simulation of ionization condition test. 147

L.17 Comparative performance for CLR and NCLR by conditioning the gap for 5 minutes 149

L.24 Comparative performance for CLR and NCLR by conditioning the gap for 10 minutes 152

L.31 Comparative performance for CLR and NCLR by conditioning the gap for 15 minutes. 156

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LIST OF FIGURES

FIGURE NO TITLE PAGE 1.1 The advantage of initiation advance of the ESE as

claimed by its manufacturer. The unique efficiency of the Pulsar lightning conductor is based on a specific initiation advance, well before the natural formation of an upward leader [2] 2

1.2 Protected area of the ESE system [2] 3 2.1 Few examples of lightning activities 14 2.2 Timing diagram of a lightning stroke 16 2.3 Paul Mortimer shows off his lightning-struck shirt 18 2.4 A Willow Run apartment building was struck by

lightning and burned Sunday night 19

2.5 Lightning striking a tree 19 2.6 The most conventional lightning rod FR 25 2.7 Cone of protection for FR lightning protection system.

(Class I= 15°, Class II= 30°, Class III= 45°) 26

2.8(a) Prevectron, Sparking ESE [24] 27 2.8(b) Inceptor, Sparking ESE [24] 27 2.8(c) DAS 28 2.8(d) Dynasphere [24] 28 2.9 Ascending discharge on Pulsar during the test

procedure at Institute de recherche d'Hydro-Quebec (IREQ) in Canada [2] 29

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2.10 The Pulsar unit has been tested under the HV in the laboratory [2] 30

2.11 Three different models of Pulsar non-conventional air

terminal [2] 32

2.12 HV block construction of the electric device inside the metallic cylinder of the Pulsar [2] 33

2.13 Comparison of the space charge-free electric field decay in the first meter above a blunt and sharp lightning rod [28]. 37

2.14 Field distribution above a lightning rod with and without the influence of a space charge volume of average density 0.25µCm-3 [28]. 38

3.1 Front view of the air terminals location on the rooftop of P18 44

3.2 Schematic diagram for front view of the lightning detection system (Refer Appendix G for the definition of the symbols use) 45

3.3 FR with the installed LFC 46 3.4 ESE with the installed LFC 47 3.5 Continuous Pulsing Generator (CPG) used in the

laboratory test . 49

3.6 Operating Terminal (OT 270) 50 3.7 Digital Measuring Instrument (DMI 551) 50 3.8 Configuration of the MIG in the IVAT laboratory

test room 51

3.9 DIAS 733 52 3.10 16.4cm in diameter of HV Rogowski plan 53 3.11 Geometries profile of the electrodes (A, B and C)

used in the test 55

3.12 Geometries profile of the electrodes (D, E and F) used in the test 56

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3.13 Rods A, B and C; D, E and F are in same height of 70mm and 64mm respectively. Rod d1 and d2 show the equal distance between each rod, where d1=80mm, d2=65mm 56

3.14 Interchanging of location for each terminal. This procedure is repeated for the second set of the test using samples D, E & F. 57

3.15 Schematic diagrams of the experimental arrangements 57 3.16 Test set-up for the NCLR system, which represent ESE

air terminal 59

3.17 Schematic diagram of electrode arrangement for NCLR 59 3.18 Configuration of electrodes for CLR, which represent

the FR 60

3.19 Test set-up for NCLR system 60 3.20 Test set-up for CLR system 61 3.21 Configuration electrode in the comparative performance

test 62

4.1 Reading on the LFC of the FR 65 4.2 Reading on the LFC of the ESE system 65 4.3 Flash density mapping in Johor from 1995 to 2000 66 4.4 Comparative performance for A, B and C rods in the firs

series of the test 69

4.5 Comparative performance for D, E and F rods in the second series of the test 69

4.6 Performance of the rod with various angle of curvature of the rod tip 71

4.7 Tb/d is plotted over the Vb/d for CLR and NCLR 73 4.8 Initiation advance (∆T) of NCLR over CLR 75 4.9 Data of total 60 shots for both tested rod 76 4.10 Number of discharge terminating at the conditioning

rod used in the first series of the test is plotted against the conditioning duration 79

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4.11 Number of discharge terminated at non-conventional rod 80 4.12 ESE terminal on the top of a high-rise building at KMJ 83 4.13 Damaged MOV unit 84 4.14 FR on the rooftop of the M&E building 86 4.15 ESE terminal on the rooftop of a building at Marina Park 88 4.16 Measuring the ground resistance at apartment houses 89 4.17 Three possibilities of streamer-leader interception for

ESE air terminal. Point N is the normal striking distance (ds) of the FR 91

4.18 Time difference between the times of initiation of current from two terminals 92

4.19 Distribution of electric field at the tip of a rod by altering the data obtained from Figure 2.14 provided

by DAlessandro in [28] 99

B.1 Lightning activities occur at power grid. 116 B.2 Ribbon lightning 116 B.3 Sand hit by lightning 117 B.4 Cacti hit by lightning 117 B.5 Image of ball lightning. 118 H.1 Lightning detection systems at WCC, Faculty of

Electrical Engineering, UTM. Picture view is taken from the Maxis telecommunication tower 129

H.2 Lightning detection system at WCC (front view). 130 H.3 View at the rooftop of the WCC building. 130 H.4 ESE on the rooftop of the WCC building. 131 H.5 FR on the rooftop of the WCC building. 132 H.6 FR is supported by stay wires 132 I.1 Switching impulse with 80.672kV of crest voltage 133

xvii

J.1 Electrode arrangement of air terminals (A, B and C). 136 J.2 J.1: Electrode arrangement of air terminals (D, E and F). 137 K.1 Reference map in Johor area 138 K.2 Individual lightning stroke data in Johor area 139 L.1 Breakdown characteristic of rod A 140 L.2 Breakdown characteristic of rod B 141 L.3 Breakdown characteristic of rod C 141 L.5 Breakdown characteristic of rod D 143 L.6 Breakdown characteristic of rod E 143 L.7 Breakdown characteristic of rod F 144 L.10 Breakdown characteristic of CLR (simulation of

Ionization condition) in sample A. 145 L.11 Breakdown characteristic of CLR(simulation of ionization

condition) in sample B 146 L.12 Breakdown characteristic of CLR (simulation of ionization

condition) in sample C 146 L.14 Breakdown characteristic of NCLR (simulation of

ionization condition) Sample A 147 L.15 Breakdown characteristic of NCLR (simulation of

ionization condition) Sample B 148 L.16 Breakdown characteristic of NCLR (simulation of

ionization condition) Sample C 148 L.18 Breakdown characteristic of CLR in the comparative

performance test with 5 minutes of conditioning duration Sample A 149

L.19 Breakdown characteristic of CLR in the comparative

performance test with 5 minutes of conditioning duration Sample B 150


performance test with 5 minutes of conditioning duration Sample C 150

xviii

L.21 Breakdown characteristic of NCLR in the comparative performance test with 5 minutes of conditioning duration Sample A 151

L.22 Breakdown characteristic of NCLR in the comparative






L.26 Breakdown characteristic of CLR in the comparative performance test with 10 minutes of conditioning duration Sample B 153











L.33 Breakdown characteristic of CLR and NCLR in the

comparative performance test with 15 minutes of conditioning duration Sample B 157



xix

L.35 Breakdown characteristic of NCLR in the comparative performance test with 15 minutes of conditioning duration Sample A 158

L.36 Breakdown characteristic of NCLR in the comparative performance test with 15 minutes of conditioning duration Sample C 158

xx

LIST OF ABBREVIATION AC - Alternating current

Ave - Average

BSI - British Standard Institute

CA - Cloud-to-Air

CC - Cloud to cloud

CEC - Corona emission current

CG - Cloud-to-Ground

CLR - Conventional lightning rod

CPG - Continuous Pulsing generator

CTS - Charge transfer system

DAS - Dissipation array system

DC - Direct Current

DIAS 733 - Digital Impulse Analyzing System

DMI 555 - Digital Measuring Instrument

e.g - For example

ESE - Early streamer emission

etc - Etcetera

Fig - Figure

FR - Franklin rod

HV - High voltage

IC - Intra cloud discharge

IEC - International Electrotechnical Commission

IREQ - Institute de Recherche d'Hydro-Quebec

KERI - Korea Electrotechnology Research Institute

KMJ - Johor Matriculation College

LCD - Liquid Crystal Display

LED - Light-emitting Diode

xxi

LFC - Lightning flash counter

LP - Lightning protection

LV - Low voltage

M&E - Maintenance and Engineering

MOV - Metal oxide variastor

NCF - National Fire Code

NCLR - Non-conventional lightning rod

NFPA - National Fire Protection Association

No. - Number

NPL - National Lightning Protection Corporation

OT 270 - Operating terminal

TV - Television

USA - United State America

UTM - Universiti Teknologi Malaysia

WCC - Wireless Communication Center

xxii

LIST OF SYMBOL

% - Percentage

/ - Per

< - Less than

= - Equal

> - Greater than

≥ - Greater or equal to

° - Degree

°K - Kelvin

A - Ampere

A - Area

C - Coulomb

cm - Centimeters

D - Distance

D - Charge density

ds - Normal striking distance

E - Electric field

EFC - Field that needed to start a corona discharge

(streamer) at the surface of a lightning rod

Ei - The leader onset field

Eion - The ionization electric field

EL - The leader propagation field

Es - Corona onset field

f - Discharge frequency

h - Height of the terminal tip above the element(s)

to be protected

Hz - Hertz

I - One

xxiii

II - Two

III - Three

k - Kilo

k, K1, K2, K3, n, b - Constants

M - Mega

m - Meters

m/s - Meters per second

mins - Minutes

mm - Millimeters

ms - Millisecond nd - Second

Ng - Frequency of earth flash

Q - Charge

R - Ground resistance

r - Radius

R - Tip radius of curvature for a conductor rod

Rp - Radius of protection in a horizontal plane

located at a vertical distance h from the tip of

the non-conventional lightning rod

t - Duration of energization time

Tb/d - Time-delay-to-breakdown

V - Volts

Vb/d - Breakdown voltage

α - Ionization coefficient

β - Field intensification factor

∆L - The distance advantage or gain in lead distance

∆T - Initiation advance or gain in spark over time of

the upward leader measured in laboratory

conditions

ε - Permittivity

η - Attachment coefficient

θ - Angle

µs - Microsecond

xxiv

ν - Average speed of the downward tracer

ν - Propagation speed of the downward leader

ν+ - Propagation speed of the upward streamer

Ω - Ohm

xxv

LIST OF APPENDIX APPENDIX TITLE PAGE A Terminology 113

B Lightning Photo 116

C Lightning Protection as Refer to the NFPA 780 119

D Certificate of Test Witnessing by BSI 124

E Radius of Protection for Pulsar 125

F Prevectron 4 126

G Description of Symbols used in Figure 2.2 128

H Pictures of LP Systems at WCC, UTM 129

I 50% Breakdown Voltage, V50 and the

Switching Impulse 133

J Geometry Profile of the Rod Used In the

Laboratory Test 136

K Lightning Strike Data Provided By TNB Research 138

L Laboratory Results 140

M Publication 159

CHAPTER 1

INTRODUCTION

1.1 Overview on the Principle of Early Streamer Initiation Mechanism ESE LP system is a relatively new approach in solving the perennial problem

of lightning damage installation, which has been equipped with FR system. The new

system is believed to be providing more effective protection against lightning than

would a FR. However, the scientific and technical basic for this improved system has

yet to be justified by field result. This therefore inevitably lead to the situation, which

the efficacy of these technologies still remains, opened to questions.

And thus, the effectiveness of these systems has been hotly debated since

early 1980, where the ESE air terminals are claimed to be able to initiate the

connecting upward streamer earlier in time than would a simple air terminal in the

same position, and are therefore claimed to be able to attract the lightning discharge

from a larger distance than would a simple air terminal [1]. Therefore, theoretically

ESE LP system supposedly requires fewer air terminals and can be placed at a farther

distance apart than the traditional FR, yet still providing superior performance.

Since there have plausible theories supporting ESE technology, the number of

users of this system is continuously increasing. But a better understanding is needed

in order to make meaningful quantitative comparisons between both systems. It is

needed to do so as LP system has played a very important role in giving protection to

users to prevent any damages either loss of lives or properties.

2

When the lightning approaches the ground, a luminous ascending brush

discharge is initiated at the lightning conductor. In the case of the conventional

lightning rod or so-called FR, this ascending brush discharge propagates in the

direction of the descending leader after a long transition phase. The ESE type of

Non-Conventional Lightning Rod (NCLR) will act to reduce the required time for

the formation and continuous propagating of the ascending discharge and enabling a

higher efficiency for the lightning capture than a FR terminal. This is as illustrated in

Figure 1.1.

Figure 1.1 The advantage of initiation advance of the ESE as claimed by its

manufacturer. The unique efficiency of the Pulsar lightning conductor is based on a

specific initiation advance, well before the natural formation of an upward leader [2].

Nowadays, the usage of the ESE LP system is very wide especially in Asia.

Several types of ESE devices have been introduced in the market to date where each

type is claimed to have different protection radius as stated by the manufacturers.

The earliest and most frequently used of ESE device is the radioactive non-

conventional air terminal [3]. But most countries have banned it, as it is believed that

its radioactive source positioned near the top of the terminal is harmful to the health.

The most common use of non-radioactive ESE devices in Malaysia is the Pulsar

(developed by Hélita, France) and Dynasphere (developed by Erico, Australia).

3

The radius of protection, Rp of an ESE device as shown in Figure 1.2 is given

by French standard NF C 17-102 (July 1995) [2, 4]. It depends on the initiation

advance, ∆T of the ESE device.

Figure 1.2 : Protected area of the ESE system [2]. From [2, 4], the radius of protection, Rp is given by ( ) ( )L2DL2 ∆+∆+−= hDhRp ; (For h ≥5m) (1)

where

Rp : Radius of protection in a horizontal plane located at a vertical

distance h from the tip of the ESE type of NCLR.

h : Height of the terminal tip above the element(s) to be protected

D : 20m for level of protection I

45m for level of protection II

60m for level of protection III

∆L (m) : the distance advantage or gain in lead distance.

4

The distance advantage, ∆L is given by

∆L = ν∆T (2)

where

ν (m/µs): average speed of the downward tracer (2x104 m/s).

∆T (µs) : initiation advance or gain in spark over time of the

upward leader measured in laboratory conditions

(3) ESEFR TTT −=∆

For terminal height lower than 5m, the respective values of Rp can be

obtained from the table provided by the French Standard NF C.

So the excellent performance in LP comes from the ability to cause earlier

initiation of the upward continuous streamer than a FR under the same condition of

lightning stroke. It can be seen from the equation (2) that radically ∆T decides the

capability and effectiveness of the NCLR, so it is the parameter where most parties

are interested in. To have better understanding on the function of the ESE LP system,

the operating principle of two types non-conventional devices are chosen to be

discussed in the next chapter.

1.2 Review of Previous Works

According to Zipse [5], the ESE enhanced ionizing (non-conventional) air

terminal can be considered to be consisted of a FR with a radioactive radium and or

thorium source for the generation of ions and connected to a special down conductor

attached to an earthing system. The use of the radioactive type of ESE air terminal

has been banned by most of the countries in the world, as it is believed that the

spreading of radioactive sources over the building and cities can be harmful to

5

human. Therefore, the performance of this kind of air terminal will not be

investigated in this work.

But, radioactive sources which were used in comparative performances

between the ionizing and non-ionizing air terminals in the laboratory is acceptable as

it is one of the alternatives that has been used to obtain ionization of the air

surrounding the tip of the air terminals.

All researches and the outcomes of past works that have been done by other

researchers elsewhere are as follows. Some of these outcomes indicate that the

significant superiority of the ESE LP system. However, there are some outcomes that

do not show any advantages as compared to the FR system.

1.2.1 Outcomes that Indicate the Relative Superiority of the ESE Lightning

Protection System (i) Several outdoor tests have been carried out in the USA and Australia.

According to Zipse [5] the performance of the ionized air terminals are more

effective in attractive lightning strike than the non-ionized FR. Such field-testing are

continuously been carried out as the field tests are more indicative of the actual

condition than the controlled short distance between the terminals and the overhead

mesh used for the laboratory testing.

Based on the result obtained from these field studies, there has been a work

made by NFPA to adapt the performance of non-conventional LP as a reference

when determining LP for any installation. The reference procedure has been

developed into standard No 781 entitled LP System Using ESE Air Terminal.

(ii) Allen et al in [6] carried out a study on the performances passive FR

(grounded rod) and active FR (subsidiary 1/50µs under simulated lightning storm

6

conditions. They found that the active FR reduces the time to spark over by between

40µs and 70µs, compared with that for the passive FR.

(iii) Allen et al in [7] have adopted a methodical approach for examining, under

laboratory conditions, the discharge emanating from an air terminal can be

influenced by voltage application to the tip of the air terminal; since such voltage

application is one technique employed by ESE air terminals to expedite upward

leader inception relative to a FR. They observed that a reduction of 10µs for

energized lightning rod was achieved in the authors experiments when compared to

the case for the rod where no lightning impulse was applied. According to the

authors, result obtained in this work is only the preliminary observations. More

experiments need to be carried out before any conclusive results can be made.

(iv) Heary et al in [8] and [9] compared the performance of the ionizing and non-

ionizing air terminals under outdoor test condition. The test condition was prepared

so as to resemble the natural operating condition of the LP when used. Radioactive

sources were used to ionize the air surrounding the tip of the air terminal. Tests were

made during both rain or frog and fine weather with the natural bias produced by the

clouds above the testing is also under artificial bias.

Both air terminals had exactly same geometrical configuration in each test

conducted. The standard or non-radioactive air terminals chosen was the FR. The

objective of this experimental study was to study the influence of ionization at the tip

of the air terminals on the probability of flashover with a specific focus upon

comparison of the ionizing air terminal to an identical air terminal without a

radioactive source, under realistic condition.

Results obtained indicate a substantial superiority of the ionizing air terminal

when tested under realistic conditions. These results are in agreement with those

obtained in the field installation of various air terminals obtained by Allen et al [9],

where in a study period of 4 months, only the ionizing terminals has been struck by

natural lightning with total number of 4. These authors also discovered that sharp air

7

terminal is more effective in attracting flashover than blunt lightning rod. This

observation is however in contrast to the experimental result obtained by Moore et al

[10, 11, 12] in their finding over past 7 years, where more blunted rod has been

founded to be a better lightning receptor.

(v) The study by British Standard Institute (BSI) [13] on the triggering advance

of the ESE lightning conductor from one manufacturer gives a figure of 54µs

compared with the simple rod lightning conductor (Refer to Appendix D). BSI has

witnessed testing of this item and the result of the test is as shown in the Report of

Test Witnessing. The full details of BSIs finding are given in the Report No

227/005069 dated 2nd November 1999.

(vi) Allen et al [14] investigated the performance of simulated ESE, which is one

of the non-conventional terminal developed and widely used. A positive auxiliary

voltage impulse, of profile 1/30µs of sufficient amplitude to produce corona has been

applied independently at the rod at controlled, variable times during the rise of the

slow-front field. The effects of this pulse on the corona produced at the rod by the

negative impulse at the plane, on the breakdown voltage of the gap, and on the times

to breakdown have been recorded. Assessment of the impulse corona behavior shows

that the auxiliary pulse had little measurable effect unless it aided the immediate

formation of a leader, or unless the slow-front impulse field had already formed a

leader.

(vii) Grzybowski et al [15] had conducted tests at Mississippi State University HV

Laboratory, USA to compare the performance of the ionizing and non-ionizing air

terminals in 1997. Two types of air terminals with different operation principle were

tested for their ionization capability under conditions simulating the quasi-static

electric fields expected below a thunderstorm. Type 1 terminal used a number of

outrigger electrodes to capture ions at their extremity, and transfer charge to produce

repetitive arcing near the central grounded electrode. Type 2 terminal were spherical

in nature and designed to inhibit discharge under high levels of electric field above

the sphere.

8

The primary difference between these terminals is that the type 1 is reactive

to static fields in the pre discharge phase, which will produce copious ions in the

vicinity of, and above the central electrode. On the other hand, the type 2 terminal is

passive under steady fields and only reacts to the approach of a down leader.

In the strokes to air terminals test, the screen charged with both positive and

negative polarities standard lightning impulse of 1.2/50µs was placed at 5m above

the ground. 2m long rod was used to simulate the downward leader. The tips of the

terminals were 1m above the ground and the separation between the terminals was

2m.

In the case of negative polarity at screen result shows that the long tip type 2

receives the strokes in the ratio of 22/40 and 18/40 in favor of type 1 but this

advantage was neutralized in the case of positive polarity at screen with each

terminal receiving an equal number of strokes.

In the short series of impulse Critical Flashover (CFO) test, the result showed

an expected lower strike voltage with the type 1 terminal. Lastly, the type 1

emissions started at low levels of electric field stress in the corona emission current

(CEC) measurement. The authors conclude their finding by proposing a plan to

progress their work to a series of tests in which various levels of permanent Direct

Current (DC) bias voltage are applied before and during the superimposition of

impulses.

1.2.2 Observations which Do Not Indicate Significant Advantage of the ESE

Lightning Protection System (i) Mackerras et al [1] made a conclusion that non-conventional (including ESE)

air terminals are not significantly different from the collection distances of simple air

terminals. They cannot have collection distances up to 50m greater than the

collection distances of simple air terminals.

9

(ii) Moore et al [10, 11 and 12] have carried out the outdoor field test under real

lightning condition in New Mexico for past seven summer thunderstorm seasons. In

an effort to compare the strike reception effectiveness of lightning rod with various

tip configurations, pairs of various sharp-tipped and blunt rods have been exposed

beneath thunderclouds to determine the better strike receptor. Result obtained after

seven years of tests shows that none of the sharp FR or ESE has collected any strike,

but 12 blunt rods with tip diameters ranging from 12.7mm to 25.4mm have taken

strike.

(iii) Lee et al [16] performed lightning impulse voltage test, flashover direction

test and CEC test on a comparative test of a particular type of ESE air terminals and

DAS with a simple rod had been carried out in the Korea Electrotechnology

Research Institute (KERI). The results obtained from this experiment in this paper

show that the characteristics of special air terminals are not superior to a simple rod

for lightning and switching impulse voltages. In the discharge time, the ESE is

averagely 2µs earlier to discharge than that of the simple rod.

Apart from this, there was no manifest evidence to verify the effects of ESE

air terminals through the comparative assessment test under the same electro-

geometrical condition where discharge number to the ESE air terminal was 61 and to

the simple rod was 55, and the rest did not has any discharge throughout experiments

of 120 times. They have concluded that if simple rod was installed on the building, it

is not a practical idea to replace it with ESE terminals as study shows that there is no

outstanding improvement for the ESE lightning rod.

(iv) According to Uman et al [17], various tests in the field and the laboratory

have shown that radioactive rod does not have or only has little significant different

from a similarly installed conventional rod of the same height (e.g. Muller-

Hillebrand 1962b; Baatz 1972). One of such observations is the failure of radioactive

LP systems in Singapore, where at the time of their study, over 100 such systems

were installed. Another observation is the failure of a radioactive lightning rod to

give the protection to the papal crest off Bernini Colonnade at the Vaticanin in 1976.

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Based on these surveys, NFPA conclude that there was no basis for issuing a

standard for ESE systems.

(v) Hartono and Robiah in [18] have done long-term studies on the performance

of ESE air terminal in Malaysia. Two cities, Kuala Lumpur and Shah Alam where

the average annual thunderstorm day of about 250 has make it a very ideal location

for the field testing of lightning air terminals.

Their studies show that the ESE terminals do not provide the enhanced

protection as claimed by their proprietors as some of the buildings equipped with one

or more of the devices had been struck by lightning repeatedly over a period of time.

Besides, the lightning damaged locations had been found to be very near to and, in

many instances, at a lower height than the position of the ESE air terminal.

1.3 Objectives of the Study To date, there is still no concrete evidence showing that the ESE type of

NCLR does provide better protection although there is many researches finding

indicate the superiority of NCLR over the FR of CLR. Thus, the objectives of this

research are

• To investigate the relation of the early streamer emission device (pulsing

unit) to the ability to launch the upward streamer

• To determine the significance of conditioning the air above the rod tip, and

• To find out the effect of geometrical configuration on the interception ability

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1.4 Contributions of the Project

Through the limited publication on the ESE LP system, it is found that work

on studying the effect of conditioning the gap above the air terminal can be found

nowhere. Most of the overseas researchers conducted their tests by applying an

auxiliary pulse of impulse shape to the rod. Small impulse generator is used to

generate this impulse at a controlled delay time varied in steps of few tens

microsecond after the start of main switching impulse. While for my work, a

continuous or repetitive pulse is connected to the rod to create an ionization

condition at the tip of the rod. This can help to enhance the electric field strength

above the tip and thus increase the ability of sending up the streamer successfully.

Results obtained from my work provide very useful information for the manufacturer

to improve their current design.

From extensive experimental results and analysis, it is discovered that shape

of a rod tip does bring a significance effect on the lightning interception ability by

enhance or inhibit the streamer initiation. Furthermore, it is found that very little

works have been done on this issue. Although overseas researchers such as Moore et

al have conducted lots of tests studying the effect of the geometrical profiles on the

performance of a rod, they change the diameter of the rod instead of varying the

curvature and angle of the rod. Results obtained from the laboratory tests on the

geometrical profiles in this work provide another good idea for manufacturer in

designing a better lightning rod.

According to my study from literatures, lots of works have been done on the

comparative performance test in the laboratory instead of field tests. Nobody has

published detail work on the study that uses the actual ESE and FR with the complete

set of Lightning Flash Counter (LFC) unit under the real lightning condition in

elsewhere, especially in Malaysia and any countries in Asia. Apart from this, works

carried out by local researchers are more on the physical treatments that focus on the

damage of buildings. Thus, statistical data on this comparative performance test

between these two types of LP system is still lacking. And hence, the lightning

12

detection systems that have been set-up at black P18, UTM provide a life comparison

between both systems.

1.5 Scope of Study

The study focuses on the streamer initiation ability of an ESE LP system. A

non-conventional air terminal from a manufacturer, which has been installed in the

campus, is monitored for its ability to intercept lightning stroke. Factors, which

inhibit or enhance this phenomenon, are studied. Observations, which result from

these factors such as the time-delay-to-breakdown, are studied. The scope also covers

field and laboratory works on set-up to give observation, which allows the

intercepting ability of the ESE LP to be analyzed.

The scope excludes detail study on the earthing system of the building, which

has been fitted with both the FR and ESE air terminals. Apart from this, bias field

due to the cloud, detail study on design of the device, field and current emission,

material of the air terminal and ratio of the air terminal height to the curvature are not

included in this study due to certain limitations of equipment available at the IVAT

laboratory.

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1.6 Summary of Thesis Chapters

This thesis consists of six chapters, namely:

I. Chapter 1 describes briefly on the overview of the principles of early

streamer initiation mechanism, review of previous works or study on the

performance of the ESE LP system compared to the FR, objectives of this

project, scope of study and the contribution of the project in the improvement

of the LP system

II. Chapter 2 contains the brief introduction related to the lighting activity such

as lightning phenomena, lightning discharge mechanism, risks and effects

from lightning strike. This chapter also discuss in brief on the types of LP

system, their categories and classification of the LP technique. Differences in

between the conventional and non-conventional have been discussed too.

III. Chapter 3 thrash out three different approaches that had been adopted in this

work namely field testing site survey and experimental works. Set-up for

several number of tests conducted has been clarified in this chapter.

IV. Discussion and analysis on the results obtained from the above-mentioned

methods have been described in Chapter 4.

V. Conclusions on the works that have been done in this project are made in

Chapter 5.

VI. Some suggestions have been proposed in Chapter 6 with hopes that more

convincing and realistic results can be obtained in the future before any

conclusions are made.

Documents

A STUDY ON THE EARLY STREAMER EMISSION (ESE) …eprints.utm.my/id/eprint/5774/1/NguEngEngMFKE2004.pdfSistem penangkap kilat Early Streamer Emission (ESE) adalah merupakan teknik agak