AUTOMATIC RESIDUAL CURRENT DEVICES AHMAD KHAIRUDDIN BONARI A project report ...

37 Pages·2015·0.77 MB·English

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AUTOMATIC RESIDUAL CURRENT DEVICES

AHMAD KHAIRUDDIN BONARI

A project report submitted in partial fulfillment of the
requirement for the award of the degree
Master of Electrical Engineering

Faculty of Electrical and Electronic Engineering
University Tun Hussein OnnMalaysia

JULY 2015
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ABSTRACT

Power system protection is the most important requirement in the industrial or
domestic electrical to prevent equipment from damage cause by leakage current. The
RCD is an important equipment to install at each of house, hospital, factory, or every
place that need the power supply. The device monitors input current from power line
by using current sensor and send the signals to the mechanical switch to trip the
circuit breaker. Industrial operation requires protection of their equipment from the
lightning short circuit and also over-current, thus the RCD will serve the purpose as
the protection of their system .This researchwill attempt to improve the exciting RCD
design using PIC microcontroller to automatically switch it back to normal when the
RCD tripped in home during instantaneous over current or short circuit. This system
provides a convenient way for house’s owner especially during absences in home. In
this research PIC 16F877A microcontroller is used to control overall flow operation
and operate the relay, thus replacing the current mechanical switch. The outcome of
this research after several testing process shown that the average sensitivity valuefor
RCD against leakage current is 76mA better 24% than 100mA set by manufacture.
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ABSTRAK

Perlindungan sistem kuasa adalah keperluan yang paling penting di dalam indusrtri
atau pun sambungan domestic elektrikal bagi mengelakan kerosakan peralatan
disebabkan oleh arus bocor. RCD adalah salah satu peralatan penting yang di pasang
di setiap rumah, hospital, kilang atau pun tempat yang memerlukan bekalan kuasa.
Peralatan ini bertindak sebagai pemerhati arus masukan dari talian kuasa oleh
pengesan arus dan kemudianya ia menghantar isyarat tersebut ke suis mekanikal
untuk terpelantikkan pemutus litar. Operasi industry memerlukan perlindungan
mesin mereka daripada kilat, litar pintas dan juga lebihan arus, maka RCD ini akan
di gunakan bagi perlindungan kepada sistem mereka. Projek ini adalah bertujuan
untuk menambahbaikan rekabentuk RCD yang sedia ada menggunakan PIC
pengawalmikro untuk menyambung kemba lilitar RCD yang telah terpelantik kepada
keadaan asal apabila berlakunya litar pintas dan lebihan arus. Sistem ini memberikan
manfaat kepada pemilik rumah apabila tiada di rumah. Didalam projek ini
PIC16F877A pengawal di gunakan untuk mengawal keseluruhan sistem
pengoperasian dan Geganti yang manatelah di tukarkan kepada suis mekanikal asal.
Hasil di akhir projek ini, setelah beberapa kali di uji didapati kepekaan RCD
terhadap arus bocor adalah 76mA di mana 24% lebih baik daripada 100mA telah
ditetapkan oleh pembuat.
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TABLE OF CONTENTS

TITLE i
DECLARATION ii
DEDICATION iii
ACKNOWLEDGEMENT iv
ABCTRACT v
ABSTRAK vi
TABLE OF CONTENT vii
LIST OF TABLES x
LIST OF FIGURES xi
LIST OF ABBREVIATIONS xii
LIST OF APPENDIXS xiv
CHAPTER 1 INTRODUCTION 1
1.1 Project background 1
1.2 Problem statement 3
1.3 Objective 4
1.4 Scopes of project 4
1.5 Report outline 4
CHAPTER 2 LITERATURE REVIEW 6
2.1 Introduction 6
2.2 Residual Current Devices (RCD) 6
2.3 RCD features 7
2.4 RCD design 9
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2.5 Operation of RCD trip situation 11
2.5.1 Permanent failure or permanent damage 11
2.5.2 Temporary failure or temporary damage 11
2.6 Electrical faults 12
2.6.1 Over-current fault 12
2.6.2 Short-circuit fault 12
2.6.3 Lightning fault 13
2.7 Literature review of previous report 14
2.7.1 Automated electrical protection system for
domestic application 14
2.7.2 Development of earth leakage circuit
breaker with an auto re-closer 15
2.7.3 Automatic earth leakage circuit
breaker with backup supply 16
2.7.4 Automatic RCD integrated with arduino 17
2.8 Conclusion for previous report 18
CHAPTER 3 METHODOLOGY 19
3.1 Introduction 19
3.1.1 Phase 1: Project planning 20
3.1.2 Phase 2: Circuit diagram 21
3.1.3 Phase 3: Software development 22
3.1.4 Phase 4: Hardware design 22
3.1.5 Phase 5: Testing 22
3.1.6 Phase 6: Maintenance 22
3.2 Prototype design 23
3.3 Overall system 24
3.4 Software development 25
3.5.1 Block diagram description 26
3.5 System operation 27
3.6 Circuit stage 29
3.6.1 Voltage regulator circuit 29
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3.6.2 LCD circuit 30
3.6.3 Relay driver circuit 31
3.6.4 Current sensor 31
3.7 Proteus software 32
3.8 MPLAB software 33
3.9 SketchUp software 34
3.10 Microcontroller (PIC 16F877A) 35
3.11 Current sensor 36
3.12 LCD display 37
3.13 Relay 37
CHAPTER 4 RESULT AND ANALYSIS 39
4.1 Result of automatic residual current devices 39
4.2 Result of programming for ARCD 41
4.3 Result Stability, durability and efficiency testing 43
4.4 Analysis 44
4.5 Analysis of time sequence 44
4.6 Analysis of current sensor detection 44
4.7 Analysis during normal and fault condition 45
4.8 Calculation percentage between theories
with the actual voltage 46
4.9 RCD test using relay test unit 48
CHAPTER 5 CONCLUSION AND RECOMMENDATION 51
5.1 Conclusion 51
5.2 Future recommendation 52
REFFERENCES 53
APPENDIXS 55
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LIST OF TABLES

4.1 ARCD Sequences 43
4.2 Stability, durability and efficiency testing 44
4.3 Time sequences 45
4.4 Measuring voltage and current using differences equipment 48
4.5 Result for RCD test 49
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LIST OF FIGURES

1.1 Short circuit 1
2.1 Home RCD/RCCB with Housing 8
2.2 The System inside RCD 8
2.3 Residual current devices 9
2.4 Residual current devices design schematic 10
2.5 Operation of the ZCT 11
2.6 Prototype of automatic electrical protection system
for domestic application 14
2.7 Prototype of ARCD with backup supply 16
2.8 Prototype of automatic RCD integrated with arduino 18
3.1 Project planning 20
3.2 Phase planning 21
3.3 Prototype sequence event 23
3.4 Internal Prototype 24
3.5 Flowchart of Overall System 25
3.6 System block diagram 26
3.7 Flowchart of system operation 28
3.8 Overall circuit of RCD 29
3.9 Voltage regulator circuit 30
3.10 PIC microcontroller and LCD circuit 30
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3.11 Relay Driver 31
3.12 Current sensor circuit 32
3.13 Proteus Interface 33
3.14 MP Lab interface 34
3.15 Main Application windows of SketchUp 34
3.16 Microcontroller overview 35
3.17 Current sensor 36
3.18 JHD 162A (16x2) structures 37
3.19 Relay 38
4.1 ARCD model 40
4.2 Control circuit 41
4.3 Program sequence 42
4.4 Current sensor sensitivity 44
4.5 Differences of voltage normal and fault without load 45
4.6 Measuring voltage and current using differences equipment 46
4.7 Test RCD at current 40mA (No trip) 48
4.8 Test RCD at current 77mA (ELCB trip) 48
4.9 Result for RCD test 51
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LIST OF ABBREVIATION

PIC Programmable Integrated Circuit
ELCB Earth Leakage Circuit Breaker
ARCD Automatic Residual Current devices
AEPSDA Automated Electrical Protection System for Domestic
Application
RCD Residential Current Device
GFCI Ground fault Circuit Interrupted
vRCD Voltage Residual Current devices
iRCD Current Residual Current devices
ZCT Zero Current Transformer
LED Light Emitting Diode