CONCLUSION Insulator Surface Condition Monitoring System For Leakage Current Analysis.

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5. CONCLUSION

99 5.1 Summary of Research 99 5.2 Attainment of Research Objectives 101 5.3 Significance of Research Objectives 102 5.4 Suggestion for Future Work 102 REFERENCES 104 APPENDICES 110 vii LIST OF FIGURES FIGURE TITLE PAGE 1.1 General illustration of insulator 1 2.1 A criterion separating leakage current into components 19 2.2 Leakage current for silicon rubber a dry surface b dry band c surface discharge d partial arch e fully arch 21 2.3 Stationary Signals 23 2.4 Non-stationary signal 23 3.1 Research Framework 34 3.2 Experiment setup for incline plane tracking test a IPT setup b DAQ card c Monitoring devices 37 3.3 Installation of test specimen for incline plane tracking test 39 3.4 Non-ionic wetting agents Triton X100 39 3.5 Conductivity Testing Meter 40 3.6 Peristaltic pump 40 3.7 Measuring and Protection Circuit 42 3.8 Sample material dimension 44 3.9 Hot-press machine Gotech 44 3.10 Pellet filled into mould plate 45 3.11 Finished material 45 3.12 Typical variation of leakage current waveform 47 3.13 Capacitive leakage current signal 48 viii 3.14 Resistive leakage current signal 49 3.15 Symmetrical leakage current signal 49 3.16 Unsymmetrical leakage current signal 49 3.17 Time-frequency representation 53 3.18 Process flow of analysing leakage current parameters 54 3.19 Test setup to measure the leakage current of the insulator 58 3.20 NI DAQ 6009 USB b Device block diagram 59 3.21 Block diagram for leakage current measurement using LabVIEW 60 3.22 Configuration of leakage current signal analysis 63 3.23 Hardware design for software system 63 4.1 a Block diagram of incline plane tracking test b Developed hardware of the incline plane tracking test 68 4.2 Voltage Divider Probe and Power Resistor 69 4.3 Electrical circuit for start, stop button and indicator lamp 70 4.4 Sparking occurred during incline plane tracking test 71 4.5 Polypropylene material condition shows erosion 72 4.6 Leakage current signal for polypropylene material 73 4.7 Leakage current patterns for polypropylene material a capacitive b resistive c symmetrical discharge d unsymmetrical discharge 75 4.8 Capacitive type for polypropylene material 76 4.9 Capacitive type for polypropylene material: 77 4.10 Leakage current of polypropylene material 78 4.11 Discharge activities on polypropylene material: afrequency spectrum b Time-frequency representation cTotal harmonic distortion dTotal non-harmonic distortion eTotal waveform distortion 79 4.12 Capacitive type for polypropylene material; acapacitive signal bspectrogram cTotal waveform distortion 80 4.13 Resistive type for polypropylene material; aresistive signal bspectrogram cTotal waveform distortion 81 ix 4.14 Symmetrical type for polypropylene material; asymmetrical signal bspectrogram cTotal waveform distortion 82 4.15 Unsymmetrical type for polypropylene material; aunsymmetrical signal bspectrogram cTotal waveform distortion 83 4.16 Completed surface condition monitoring system 84 4.17 Time frequency representation 86 4.18 Unsymmetrical leakage current parameters 88 4.19 Recorded analysed leakage current signal data 89 4.20 Data of input leakage current signal 90 4.21 Recorder and input data loader 90 4.22 Comparison of analysis results between visual basic and MatLab for leakage current symmetrical pattern 96 B.0.1 Incline plane tracking schematic diagram 114 B.0.2 Incline plane tracking test setup 114 B.0.3 Incline plane tracking final test development 115 B.0.4 Step for material preparation 115 x LIST OF TABLES TABLE TITLE PAGE 1.1 Proposed system’s interests 7 2.1 Comparison between non polymeric and polymeric 12 2.2 Strengths and limitations of homo polypropylene 14 2.3 Comparison accelerating ageing test method 15 3.1 Components in the online monitoring system 62 4.1 Range value for power resistor 69 4.2 Comparison of analysis results between visual basic and MatLab for leakage current capacitive pattern 93 4.3 Comparison of analysis results between visual basic and MatLab for leakage current resistive pattern 95 4.4 Rules Base Leakage Current Surface Condition Classification 97 C.1 Polypropylene Performances 116 xi LIST OF ABBREVIATIONS HV - High Voltage PVC - Polyvinylchloride LC - Leakage Current FFT - Fast Fourier Transform TFD - Time Frequency Distribution IPT - Inclined Plane Tracking RMS - Root Mean Square THD - Total Harmonic Distortion TnHD - Total non-Harmonic Distortion TWD - Total Waveform Distortion TFR - Time Frequency Representation VB - Visual Basic GUI - Graphic User Interface TNB - Tenaga Nasional Berhad DC - Direct Current HVDC - High Voltage Direct Current EAP - Early Aging Period TP - Transition Period LAP - Late Aging Period FT - Fourier Transform DFT - Discrete Fourier Transform STFT - Short Time Fourier Transform Hz - Frequency unit, Hertz xii ADC - Analogue to Digital Converter NI-DAQ - National Instrument Data acquisition USB - Universal Serial Bus V - Volts PP - Polypropylene UTeM - Universiti Teknikal Malaysia Melaka DAQ - Data Acquisition P.U - Per-unit System xiii LIST OF SYMBOLS wt - Observation window f s - Sampling frequency f - Fundamental frequency h - Harmonic t s - Sampling period n - Integer I RMS t - Instantaneous Root Mean Square Current I 1RMS t - Instantaneous Root Mean Square Fundamental Current I THD t - Instantaneous Total Harmonic Distortion I TnHD t - Instantaneous Total non-Harmonic Distortion I TWD t - Instantaneous Total Waveform Distortion xiv LIST OF PUBLICATIONS

1. Publications