AIZA BINTI ABDUL ADZISPemutus Litar Bocor ke Bumi terpelantik jika nilai voltan melebihi had tertentu. Voltan pusuan neutral ke bumi adalah sejenis voltan pusuan bervoltan rendah yang

SPD RESPONSE TO INTERNAL GENERATED NEUTRAL TO EARTH TRANSIENT IN LOW VOLTAGE SYSTEM

AIZA BINTI ABDUL ADZIS

UNIVERSITI TEKNOLOGI MALAYSIA

SPD RESPONSE TO INTERNAL GENERATED NEUTRAL TO EARTH TRANSIENT IN LOW VOLTAGE SYSTEM

AIZA BINTI ABDUL ADZIS

A project report submitted in partial fulfilment

of the requirements for the award of the degree of

Master of Engineering (Electrical Power)

Faculty of Electrical Engineering

Universiti Teknologi Malaysia

JANUARY 2018

iii

To my lovely parents Abdul Adzis & Zaliha and parents in law Mohd Saman & Jamaliah, who gave me endless love, trust, constant encouragement over the years, for prayers, and for taking care of our children Zihni and Irfan when we both couldn’t make it.

To my husband Khairul Anuar and children Khayrin Zihni & Harith Irfan, for being very understanding and supportive in keeping me going, enduring the ups and downs during the completion of this thesis.

To my siblings & family, for their support, love, prayers, and for taking care of Zihni and Irfan.

This thesis is dedicated to them.

iv

ACKNOWLEDGEMENT

I wish to express my most profound appreciation to all those who helped me,

in one way or another, to complete this thesis. First and foremost I thank Allah the

Almighty who provided me with strength, direction and showered me with blessings

throughout. My sincerest gratitude goes to my supervisor Dr. Noor Azlinda Binti

Ahmad for her continuous guidance and support. With her expert guidance and

immense knowledge, I was able to overcome all the obstacles that I encountered

during my journey in completing this project report. My heartfelt indebtedness goes

to the unsung heroes; my beloved family for their understanding, support, prayers

and love. Without their sacrifice, I would not be able to complete the whole Master

program here in JB. My genuine thankfulness goes to course mates, seniors and

friends for their sincere tips and kind assistance throughout the studies.

I would also like to thank Public Works Department and Government of

Malaysia for granting me the study leave. The appreciation also extended to

colleagues who shared the related reference for the research.

v

ABSTRACT

It is essential to have a steady and continuous power supply without halting due to the false triggers to ensure continuity in activities and convenience of users especially when they are dealing with sensitive equipment. It is also vital to protect the sensitive equipment from disturbance to ensure maximum lifespan. In this country, the awareness of protecting sensitive equipment from premature malfunction due to surge overvoltage is increasing with the use of widely implemented Surge Protective Device (SPD). In reality, besides atmospheric surge overvoltage, another surge namely neutral to earth transient is also threatening sensitive equipment and cause nuisance Residual Current Device (RCD) tripping if the magnitude of the overvoltage exceeds a specific figure. The neutral to earth transient is a low magnitude transient that can go up to 250 V. Factors known to contribute to the neutral to earth transient event is related to load switching activities and wiring problems. However, this kind of disturbance is less considered in low voltage distribution system although the frequency of the occurrence isliterally higher than atmospheric overvoltage. In this research, the characteristic of typical SPD circuit under the presence of neutral to earth transient is analysed to ascertain its capability in diverting the impulse voltage. Also, to understand the operation of the voltage-limiting device in the presence of surge. The analysis has been carried out by modelling and simulating the typical SPD circuit using Microcap software. The typical SPD circuit was simulated by applying 6 kV lightning impulse voltage of 1.2/50 μs, and neutral to earth impulse voltage of 1.2/20 ms from 250 V to 750 V. The 250 V input voltage represents the neutral to earth transient. The purpose of simulating the other two input voltage is to observe the behaviour of the protective clamping device in the presence of different surge level. The output voltage has been measured, and it is found that the SPD cannot clamp the 250 V neutral to earth transient. Therefore a hybrid surge protection circuit is proposed to limit the low amplitude neutral to earth transient. The proposed surge protection circuit can limit both normal mode (L_N) and common mode (L-E, N-E) transient.

vi

ABSTRAK

Kuasa elektrik yang stabil tanpa gangguan adalah satu keperluan untuk memastikan aktiviti penting dapat dilaksanakan bagi keselesaan pengguna terutamanya sewaktu sedang menggunakan peralatan yang sensititif. Perlindungan ke atas peralatan yang sensitif kepada gangguan juga adalah penting bagi memastikan jangka hayat yang maksima. Di negara ini, kesedaran untuk melindungi peralatan yang sensitif kepada gangguan arus/voltan pusuan semakin meningkat dengan memasang Alat Pelindung Arus Pusuan. Namun realitinya selain arus/voltan pusuan disebabkan keadaan semulajadi, terdapat satu lagi voltan pusuan dikenali sebagai voltan pusuan neutral ke bumi yang mengancam peralatan sensitif dan menyebabkan Pemutus Litar Bocor ke Bumi terpelantik jika nilai voltan melebihi had tertentu. Voltan pusuan neutral ke bumi adalah sejenis voltan pusuan bervoltan rendah yang mana nilainya sehingga 250 V. Faktor-faktor yang menyebabkan berlakunya voltan pusan neutral ke bumi adalah aktiviti pensuisan beban dan masalah pendawaian. Walaubagaimanapun, gangguan ini jarang mendapat perhatian dalam sistem kuasa voltan rendah walaupun kadar kekerapannya lebih tinggi dari arus/voltan pusuan yang disebabkan oleh keadaan semulajadi. Dalam kajian ini, sifat litar Alat Pelindung Arus Pusuan di analisa untuk memastikan keupayannya untuk menghadkan arus pusuan ini. Selain itu, kajian ini bertujuan untuk memerhati dan memahami operasi komponen pelindung sewaktu kehadiran voltan pusuan. Analisa telah dibuat dengan merekabentuk model litar dan membuat simulasi menggunakan perisian Microcap. Litar Alat Pelindung Arus Pusuan telah disimulasi dengan masukan 6 kV voltan pusuan 1.2/50 μs dan masukan neutral ke bumi voltan pusuan 1.2/20 ms dari 250 V ke 750 V. Masukan voltan pusuan 250 V mewakili pusuan neutral ke bumi. Tujuan membuat simulasi bagi dua kadaran lagi adalah untuk memerhatikan sifat komponen pelindung sewaktu kehadiran beberapa nilai voltan pusuan. Voltan keluaran diukur dan didapati Alat Pelindung Arus Pusuan tidak boleh mengapit voltan pusuan masukan 250 V neutral ke bumi. Oleh itu, satu litar Alat Pelindung Arus Pusuan baru telah dicadangkan untuk menghadkan voltan pusuan neutral ke bumi. Litar ini boleh menghadkan kedua-dua pusuan dari kilat dan juga dari neutral ke bumi.

vii

TABLE OF CONTENTS

CHAPTER TITLE PAGE

DECLARATION ii

DEDICATION iii

ACKNOWLEDGEMENTS iv

ABSTRACT v

ABSTRAK vi

TABLE OF CONTENTS vii

LIST OF TABLES viii

LIST OF FIGURES ix

LIST OF ABBREVIATIONS x

LIST OF SYMBOLS xi

LIST OF APPENDICES xii

1 INTRODUCTION 1

1.1 Project Background 1

1.2 Problem Statement 3

1.3 Research Objectives 4

1.4 Scope of Work 5

1.5 Research Contribution 5

1.6 Project Report Organization 6

2 LITERATURE REVIEW 7

2.1 Introduction 7

2.2 Nuisance Tripping of Residual Current Device (RCD)

and Equipment Damage

8

2.2.1 Research Related to Neutral to Earth Transient 9

viii

2.2.2 CBEMA Curve 13

2.3 Neutral to Earth Transient 14

2.4 Surge Protective Device 16

2.5 Reference to Low Voltage SPD Design 21

2.6 Reference to SPD Class II Rating 22

2.7 Recommendation from IEEE 1100 and IEEE 1159 23

3 RESEARCH METHODOLOGY

3.1 Introduction 25

3.2 The Design of Surge Protection Circuit 27

3.2.1 Maximum Continuous Operating Voltage 27

3.2.2 Maximum Clamping Voltage 29

3.2.3 Typical SPD Circuit 30

3.2.4 The Operation of Typical SPD Circuit 32

3.2.5 Proposed Hybrid Surge Protection Circuit 32

3.2.6 The Operation of Hybrid Surge Protection

Circuit

35

3.3 Input Voltage for Simulation 36

3.3.1 Impulse Voltage of 1.2/50 μs 36

3.3.2 Impulse Voltage of 1.2/20 ms 38

3.3.3 AC Voltage (Sinusoidal Waveform) 38

3.3.4 Simulation Procedure 39

4 RESULTS AND DISCUSSION

4.1 Introduction 41

4.2 Typical SPD Circuit 41

4.2.1 Simulation Result When Injected With

Impulse Voltage of 1.2/50 μs

42


Impulse Voltage of 1.2/20 ms

44

4.3 Proposed Hybrid Surge Protection Circuit 51


Impulse Voltage of 1.2/20 ms

52

ix

4.3.2 Simulation Result When Injected With AC

Voltage

54

4.4 Summary of Results 57

4.5 Comparison with the Previous Design 59

5 CONCLUSION AND RECOMMENDATION

5.1 Conclusion 62

5.2 Recommendation 63

REFERENCES 64-67

Appendix A 68

x

LIST OF TABLES

TABLE NO TITLE PAGE

2.1 Source of switching surge 17

2.2 Effect of surge 17

2.3 Minimum MCOV requirement 20

2.4 SPD Class III rated value 23

3.1 MCOV rating 28

3.2 MOV rating specification based on model 29

3.3 MOV specification 31

3.4 Definition of waveform parameter 36

4.1 Waveform and impulse for typical SPD 42

4.2 Measured limiting voltage of the typical SPD

circuits when injected with 6 kV impulse voltage of

1.2/50 μs

44


circuits when injected with 250 V impulse voltage

of 1.2/20 ms

46



of 1.2/20ms

48



of 1.2/20ms

50

4.6 Waveform and input voltage for proposed hybrid

surge protection circuit

51

4.7 Measured limiting voltage of proposed hybrid surge

protection circuit when injected with 250 V impulse

voltage of 1.2/20 ms

53

xi

4.8 Measured fault voltage at three different nodes 55

4.9 Measured N-E voltage at node 4 57

4.10 Summary of the results 58

4.11 Comparison with the previous design 60

xii

LIST OF FIGURES

FIGURE NO TITLE PAGE

2.1 Line voltage L2 becomes zero at high neutral to earth voltage 9

2.2 RCCB tripping during neutral to earth transient event 10

2.3 Voltage, current and power 11

2.4 Neutral to earth transient 11

2.5 Neutral to earth transient, RCCB tripping of red phase and yellow phase 12

2.6 Summary of neutral to earth event 13

2.7 ITI (CBEMA) Curve Revised 2000 14

2.8 Neutral to earth transient due to addition of inductive load 15

2.9 TN-C-S supply system configuration 15

2.10 TT supply system configuration 16

2.11 SPD design and topology 18

2.12 Response of SPD 19

2.13 Line to neutral circuit 21

2.14 Line to earth circuit 21

2.15 Neutral to earth circuit 22

3.1 Research process flow 26

3.2 Basic surge protection for all mode 27

3.3 Typical SPD circuit with SK20K230 30


xiii


3.6 Proposed hybrid surge protection circuit 33

3.7 Hybrid surge protection circuit at neutral to earth 33

3.8 Combination wave open circuit voltage 36

3.9 Surge generator circuit 37

3.10 Impulse voltage of 1.2/50 μs waveform 37

3.11 Impulse voltage of 1.2/20 ms waveform 38

3.12 AC voltage waveform 39

3.13 Simulation procedure 40

4.1 Comparison of input and output voltage of S20K230 when injected with 6 kV impulse voltage of 1.2/50 μs 42



4.4 Comparison of input and output voltage of S20K230 when injected with 250 V impulse voltage of 1.2/20 ms 45





4.9 Comparison of input and output voltage of S20K275 when injected with 500 V impulse voltage of 48

xiv

1.2/20 ms




4.13 Circuit with nodes identification 51

4.14 Comparison of input and output voltage measured at node 2 52

4.15 Comparison of input and output voltage measured at node 3 52

4.16 Comparison of input and output voltage at node 4 53

4.17 Fault voltage at node 2, at compulsory MOV S20K275 54

4.18 Fault voltage at node 3, at secondary circuit of step-down transformer 54

4.19 Fault voltage at node 4, at additional MOV S20K25 55

4.20 N-E voltage at node 4 at 2 V input 56

4.21 N-E voltage at node 4 at 5 V input 56

4.22 Simulation result of proposed hybrid surge protection circuit when injected with 6 kV impulse voltage of 1.2/50 μs 59

xv

LIST OF ABBREVIATIONS

AC - Alternating Current

CBMA - Computer and Business Equipment Manufacturers Association

DB - Distribution Board

ELR - Earth Leakage Relay

IEEE - Institute of Electrical and Electronic Engineers

IEC - International Electrotechnical Commission

ITIC - Information Technology Industry Council

L-N - Line to Neutral

L-E - Line to Earth

MCOV - Maximum Continuous Operating Voltage

MOV - Metal Oxide Varistor

MSB - Main Switchboard

N-E - Neutral to Earth

PRCD - Portable Residual Current Device

RCBO - Residual Current Circuit Breaker with Overcurrent Protection

RCCB - Residual Current Circuit Breaker

RCD - Residual Current Device

SLG - Single Line to Ground

SPD - Surge Protective Device

SRCD - Socket-outlet incorporating an RCD

TN-C - Terre Neutral Combined

TN-C-S - Terre Neutral Combined Separate

TN-S - Terre Neutral Separate

TT - Terre Terre

xvi

LIST OF SYMBOLS

V - Volt

kV - Kilovolt

μs - Microsecond

ms - Millisecond

xvii

LIST OF APPENDICES

APPENDIX TITLE PAGE

A Technical Data Sheet For Metal Oxide Varistor 68

CHAPTER 1

INTRODUCTION

Introduction 1.1

The quality of power in a commercial building is paramount to ensure

satisfying operation of equipment especially electronic (non-linear) equipment that

dominates most of the stuff in many parts of the world for decades ago. It is also

essential to have a steady and continuous power supply without halting due to the

false triggers to ensure continuity in activities and convenience of users.

Disturbances in the power supply that is not due to a real electrical fault can cause

inconvenience and significant loss. The most threatening disturbance that commonly

effects electronic equipment is transient due to lightning and switching effect. In the

recent years, those two troubles are the primary concern of the manufacturers and the

users of electronic equipment [1].

The lightning transient enters the service entrance through several ways

including inductive coupling and direct coupling. The capacitor bank energisation,

ferroresonance and transformer energisation (to name a few) produce switching

transient in the electrical system [2]. The lightning and switching transients are

usually of high amplitude and energy. The standard method utilised to protect

sensitive equipment from lightning and switching overvoltage in low voltage system

is surge protective device (SPD) [3]. Surge protective device is a power conditioner

between supply and load intended to suppress transient from entering power system

and the load. The primary purpose of SPD in low voltage system regardless of supply

system configuration (TT, TN-C, TN-C-S and TN-S) is to divert both normal mode

(L-N) and common mode (L-E, N-E) transient to the ground [4].

2

Not many are aware of the existence of another transient that occurs between

neutral to earth. The consequence of the transient is as harmful as the effect of the

lightning and high energy switching transient. The transient is generated internally

and a part of everyday operation. The transient leads to nuisance tripping of the

residual current device (RCD) and damage to electronic equipment. In 2008, Mohd.

Zaki Abdullah [5] observes that RCD nuisance tripping occurs when neutral to earth

transient higher than 160 V. In 2013, Mohd Zaki Abdullah et. al [6] conducted on-

site analysis and discovered that high leakage current from equipment plus high

neutral to earth voltage is the main reason for RCD nuisance tripping and equipment

damage. In 2014, Roldán-Porta et. al [7] reporting the event of RCD nuisance

tripping due to neutral to earth transient in a hospital in Spain that happened at day

one of operation. Escrivá-Escrivá et. al [8] continues to discuss this issue in another

journal published in 2016.

Problem Statement 1.2

Neutral to earth transient is a switching transient (internal load switching) that

produces an intermittence single line-to-ground fault (SLG) in the same electrical

distribution system. The amplitude of the neutral to earth transient can go up to 250

V for a duration of 20 ms [6]. The equipment that damaged due to neutral to earth

transient is typical non-linear office equipment such as computers, facsimile and

copying machine [6][7] even though the equipment is required to equip with internal

surge protection circuit according to [9]. The question that is lingering around as to

why the transient can passes through the SPD or internal surge protection circuit

without being clamped.

There are misconceptions about the capability of SPD in limiting surge

overvoltage. Prolong confusions could lead to unresolved issues. According to [10],

SPD is used to protect electrical system and equipment against various overvoltage

and impulse currents such as lightning and switching surge. In a typical design of

electrical distribution system, SPD is usually installed at least one at main

switchboard (MSB) to limit transient overvoltage and divert surge current coming

3

from outside facility to protect system and load. SPD can also be installed as close as

possible to the load to protect sensitive equipment. This type of SPD is known as

SPD Class III and it usually located at distribution board (DB). The capability of

SPD to limit transient overvoltage specifically for voltage-limiting type SPD is

dependent on the rating of maximum continuous operating voltage (MCOV).

According to [11], the minimum rating for MCOV at neutral to earth shall be equal

to or higher than 230 V. The specification of a varistor; the voltage-limiting

component assembled inside SPD with MCOV rating at 230 V (for a specific brand),

gives a clamping voltage of 595 V. Further studies of the varistor data sheet provide

the conclusion that higher rating of MCOV (more than 230 V) offers higher

clamping voltage, while a lower rating of MCOV (less than 230 V) gives lower

clamping voltage. In practice, the rating of MCOV for SPD Class III at neutral to

earth varies from 255 V to 280 V [12].

It is essential to observe the response of the typical SPD circuit in limiting

neutral to earth transient to establish an understanding on its operation and the

relationship between maximum continuous operating voltage and maximum

clamping voltage of the protective component (measured limiting voltage or let-

through voltage). The comprehension can be used to improve the surge protection

circuit so that a broad protection range can be proposed to prevent the neutral to earth

transient from disturbing power supply operation (from RCD nuisance tripping) and

to increase the susceptibility of equipment (from equipment damage).

4

Research Objective 1.3

The purpose of this research is to study and observe the response of typical

SPD circuit to the internal generated neutral to earth transient in low voltage system

regarding limiting voltage or let- through voltage. The specific objectives of this

project are as follow:

1. To simulate a typical SPD circuit by injecting high amplitude and low

amplitude input impulse voltage and measure its limiting voltage.

2. To propose a hybrid surge protection circuit designed for neutral to

earth protection mode to improve SPD response to switching transient.

3. To compare the limiting voltage of proposed hybrid surge protection

circuit with typical SPD circuit when injected with low amplitude input

voltage.

Scope of Work 1.4

The scopes and limitation of work in this project are:

1. Study the value of maximum continuous operating voltage (MCOV)

and voltage protection level of available commercial SPD Class III in

the market.

2. Design two surge protection circuits by using Microcap software based

on the typical value of MCOV and definition of SPD as defined by

IEEE, MS IEC, IEC and BS to observe their response regarding

limiting voltage. The SPD circuit is based on a single nonlinear

voltage-limiting device according to [3].

i) Typical SPD circuit

ii) Proposed hybrid surge protection circuit

5

3. The simulation for both circuits accomplished by using Microcap

software. The waveform parameter of the input voltage for high

amplitude is as defined by IEEE, MS IEC, IEC and BS (positive

waveform only) while waveform parameter for low magnitude is based

on captured data in previous research.

4. Both circuits are designed based on protection mode at neutral to earth

only.

5. The technology of the clamping device for both circuits is Metal Oxide

Varistor (MOV).

Research Contribution 1.5

This research is vital because it highlights the occurrence of low amplitude

neutral to earth transient in low voltage system that is less considered compared to

other transients. Although it is a low magnitude transient, it does affect the system

and load. The most apparent effects of the transient are RCD nuisance tripping and

equipment damage. This research is significant because it studies the response of

SPD concerning limiting voltage when simulated with neutral to earth transient. The

purpose is to ascertain the ability of SPD to give protection against this transient, as

it is the only protection device used to protect sensitive equipment from lightning and

switching transient. This research proposes a new method to limit the transient by

suggesting a hybrid surge protection circuit that can provide a broad protection range

for switching transient.

6

Project Report Organization 1.6

This thesis consists of five chapters. The description of each section is as follows:

Chapter 1: Provides overview and background of research, objectives, scope and

contribution of the research.

Chapter 2: Gives details on the literature review on the supply system configuration,

event of neutral to earth transient and the detailed topology of surge protection

device.

Chapter 3: Discusses the research methodology adopted in this project and details

procedure of project implementation.

Chapter 4: Discuss and analyse the results of the simulation.

Chapter 5: Concludes and summarise the findings and recommendation for future

work.

64

REFERENCES

[1] IEEE Standard, Recommended Practice for Powering and Grounding

Electronic Equipment. IEEE 1100-2005.

[2] IEEE Standard, Recommended Practice for Monitoring Electric Power

Quality. IEEE 1159-2009.

[3] IEC Standard, Low-voltage surge protective devices – Part 11: Surge

protective devices connected to low-voltage power systems-Requirements and

test methods. IEC 61643-11: 2011.

[4] Gomes, Chandima, and Vernon Cooray, 2010, "Surge protection of low

voltage systems and relevant standards”, 30th International Conference on

Lightning Protection-2010, Cagliari, Italy, pp 1-8.

[5] Mohd Zaki Abdullah, 2008, “Recent Advances in Electrical Earthing

System”, Journal of Engineering Science, vol 4, no. 3.

[6] Abdullah, M.Z., Ariffin, R., 2013, “Power Quality Analysis of Residual

Current Device (RCD) Nuisance Tripping At Commercial Buildings,”IEEE

Symposium on Industrial Electronics & Applications, pp. 122-125.

[7] Roldán-Porta, C., Escrivá-Escrivá, G., Cárcel-Carrasco, F.J, and Roldán-

Blay, C., 2014,“Nuisance tripping of residual current circuit breakers: A

practical case”, Electric Power Systems Research, vol 106, pp. 180-187.

[8] Escrivá-Escrivá, G., Porta, C.R., and de Jong, E.C.W.,2016, “Nuisance

tripping of residual current circuit breakers in circuits supplying electronic

loads”, Electric Power Systems Research, vol. 131, pp. 139-146.

[9] British Standard, Information technology equipment – Safety Part 1: General

Requirements. BS EN 60950-1:2006+A2:2013.

[10] British Standard, Low-voltage surge protective devices – Part 12: Surge

protective devices connected to low-voltage power distribution systems –

Selections and application principles. DD CLC/TS 61643-12: 2009.

[11] Malaysian Standard, Electrical Installations of Buildings-Part 5-53: Selection

and Erection of Electrical Equipment – Isolation, Switching and Control.

MS IEC 60364-5-53:2003.

65

[12] Electrical Material Approved List. Available from: <www.jkr.gov.my/jmal>

[1 October 2017].

[13] Dahari M. Siran, 2011, “Residual Current Devices in Electrical Installation”,

National Conference on Electrical Safety. Available from:

< https://www.st.gov.my/>.[11 December 2017].

[14] IEC Standard, Residual current operated circuit breakers without integral

overcurrent protection for household and similar uses (RCCBs) – Part 1:

General rules, IEC 61008-1:2013.

[15] Dalila Mat Said, Power Quality, lecture notes distributed in Power Quality

MKEP1563 at Universiti Teknologi Malaysia, on semester 2 2016/2017.

[16] Gomes, C., 2011, "On the selection and installation of surge protection

devices in a TT wiring system for equipment and human safety," Safety

Science, vol. 49, no. 6, pp. 861-870.

[17] IEEE Standard, Guide for The Application of Surge Protective Device For

Use on the Load Side of Service Equipment in Low Voltage (1000V or less,

50Hz or 60 Hz) AC Power Circuit.

[18] Amizah Mohd. Ariffen, 2011, Development of Class II and Class III Surge

Protective Device for Low Voltage Protection System. Master Thesis,

Universiti Putra Malaysia.

[19] Ariffen, A.M., Kadir, M. and Ahmad, W., 2011. The Development of Hybrid

Surge Protection Circuit with Effect of Adding a Filter. International journal

of engineering & technology, vol. 11, no. 2, pp.38-47.

[20] Technical Data Sheet, EPCOS Leaded Varistors. Available from:

<http://www.farnell.com/datasheets>. [1 September 2017].

[21] IEC Standard, Electromagnetic Compatibility Part 4-5: Testing and

Measurement Techniques – Surge immunity test. IEC 61000-4-5:2005.

[22] Simulating a surge pulse. Available from:

<https://www.electronicspoint.com/resources/simulating-waveforms.16>.

[28 September 2017].

[23] IEC Standard, Insulation coordination for equipment within low-voltage

systems – Part 1: Principles, requirements and test. IEC 60664:2007.

[24] Beutel, A. and Van Coller, J., 2005. The application of silicon avalanche

diodes on low-voltage power systems. IEEE transactions on industry

applications, vol. 41, no. 4, pp.1107-1112.

66

[25] Technical Data Sheet, ST 1.5KE. Available from: <http://www.st.com>.

[1 September 2017].

[26] Shafie, M. A., Singh, H., & Rahman, M. A., 2010, “Harmonic and neutral to

ground voltage reduction using isolation transformer”, Power and Energy

(PECon), 2010 IEEE International Conference, pp. 561-566.

[27] Czapp, S., Dobrzynski, K., Klucznik, J. and Lubosny, Z., 2017, June. Low-

frequency tripping characteristics of residual current devices. In Environment

and Electrical Engineering and 2017 IEEE Industrial and Commercial

Power Systems Europe (EEEIC/I&CPS Europe), 2017 IEEE International

Conference, pp. 1-4.

[28] Xiang, Y., Cuk, V. and Cobben, J.F.G., 2011, May. Impact of residual

harmonic current on operation of residual current devices. In Environment

and Electrical Engineering (EEEIC), 2011 10th International Conference on,

pp. 1-4.

[29] Khanmiri, D.T., Ball, R. and Lehman, B., 2017. Degradation Effects on

Energy Absorption Capability and Time to Failure of Low Voltage Metal

Oxide Varistors. IEEE Transactions on Power Delivery, Vol. 32, no.5,

pp.2272-2280.

[30] Paul, D., 2001. Low-voltage power system surge overvoltage

protection. IEEE Transactions on Industry Applications, Vol. 37, no.1,

pp.223-229.

[31] Cai, L., Wang, J., Cheng, S., Yang, S., Li, B. and Zhou, M., 2011, November.

SPD response characteristics in nature lightning. In Lightning (APL), 2011

7th Asia-Pacific International Conference, pp. 741-745.

[32] Li, H., Xu, N., Chen, W. and Brocke, R., 2014, October. Advanced

requirements on SPDs protecting sensitive equipment. In Lightning

Protection (ICLP), 2014 International Conference, pp. 1206-1211.

[33] Khanmiri, D.T., Ball, R., Mosesian, J. and Lehman, B., 2016, March.

Degradation of low voltage metal oxide varistors in power supplies.

In Applied Power Electronics Conference and Exposition (APEC), 2016

IEEE, pp. 2122-2126.

[34] Finis, G., Wetter, M. and Meyer, T., 2016, September. New spark-gap

technology with efficient line-follow current suppression for the protection of

67

powerful LV distribution systems. In Lightning Protection (ICLP), 2016 33rd

International Conference on, pp. 1-7.

[35] Nasiopoulou, C. and Pyrgioti, E., 2012, September. Performance of surge

arresters in a low voltage distribution system. In Lightning Protection (ICLP),

2012 International Conference on, pp. 1-6.

[36] Barbosa, C.F., Pomponi, R. and Tommasini, R., 2010, September. SPD

characteristics for equipment protection. In Lightning Protection (ICLP),

2010 30th International Conference pp. 1-8.

[37] Hotchkiss, R.W. and Mikesell, P.E., 2013, July. SPDs shown to improve the

reliability of medical equipment—A case study. In Power and Energy Society

General Meeting (PES), 2013 IEEE, pp. 1-5.

[38] Gomes, C. and Cooray, V., 2010, September. Transients that may affect low

voltage electrical systems. In Lightning Protection (ICLP), 2010 30th

International Conference, pp. 1-13.

Documents

AIZA BINTI ABDUL ADZISPemutus Litar Bocor ke Bumi terpelantik jika nilai voltan melebihi had tertentu. Voltan pusuan neutral ke bumi adalah sejenis voltan pusuan bervoltan rendah yang