표제지
목차
List of Terms and Abbreviations 8
Abstract 10
I. 서론 12
II. 연구배경 15
2-1. 지중 전력케이블의 열화현상 15
2-1-1. 수트리 (Water tree) 열화 16
2-1-2. 국부결함에 의한 열화 21
2-2. Weibull distribution function 23
III. 지중 전력케이블의 진단기법 29
3-1. 케이블 상태진단 기법 29
3-1-1. VLF (Very Low Frequency) tan δ 29
3-1-2. VLF tan δ 상태판정기준 이력 35
3-2. UCD(Used Cable Diagnosis) Matrix 39
IV. 결과 및 고찰 41
4-1. 길이보상의 필요성 41
4-2. 길이보상을 적용한 UCD 판정기준의 변화 57
4-3. R index 71
V. 결론 84
참고문헌 85
초록 90
임재성 연구 경력 목록 92
Table 2-1-1. The defects designation of cable insulation layer. 22
Table 3-1-1. Suggested criteria in IEEE/ICC fall meeting in 1996. 35
Table 3-2-1. UCD Matrix 16. 39
Table 3-2-2. Additional UCD Matrix. 40
Table 4-2-1. Reproducibility based on Group A over 300m. 64
Table 4-2-2. Reproducibility based on Group A-1 over 300m. 64
Table 4-2-3. Reproducibility based on Group A between 600m to 900m. 66
Table 4-2-4. Reproducibility based on Group A-1 between 600m to 900m. 66
Table 4-2-5. Reproducibility based on Group A over 900m. 68
Table 4-2-6. Reproducibility based on Group A-1 over 900m. 68
Table 4-3-1. Distribution of R index in length. 77
Fig. 2-1-1. The failure rate of power equipment (bath curve). 15
Fig. 2-1-2. The electrical tree and type of water tree. 19
Fig. 2-1-3. The vented tree density by AC breakdown Voltage. 19
Fig. 2-1-4. The vented tree progress by AC breakdown Voltage. 20
Fig. 2-1-5. Water tree progress by the breakdown Strength. 20
Fig. 2-1-6. The defects of XLPE cable insulation layer. 22
Fig. 2-2-1. The weibull distribution by scale parameter and shape parameter. 28
Fig. 3-1-1. The equivalent of power cable and concept of tanδ. 30
Fig. 3-1-2. The field measurement of VLF tanδ. 30
Fig. 3-1-3. The phase shift of voltage and current by water tree. 31
Fig. 3-1-4. The tanδ by frequency. 33
Fig. 3-1-5. The VLF tanδ at each grade according to test voltage. 33
Fig. 3-1-6. Vented tree density by the distribution of VLF tanδ. 34
Fig. 3-1-7. Water tree progress by the distribution of VLF tanδ. 34
Fig. 3-1-8. History of international and domestic of VLF tanδ standard. 38
Fig. 3-1-9. The diagnosis performance using the KEPCO criteria 2009 measured at 2011. 38
Fig. 4-1-1. Before compensation 1.5Uo VLF tanδ distribution by length at Group A. 42
Fig. 4-1-2. After compensation 1.5Uo VLF tanδ distribution by length at Group A. 42
Fig. 4-1-3. Compensation factor by length at 1.5Uo VLF tanδ. 43
Fig. 4-1-4. Before compensation 1.5Uo VLF tanδ distribution by length at Group A-1. 45
Fig. 4-1-5. After compensation 1.5Uo VLF tanδ distribution by length at Group A-1. 45
Fig. 4-1-6. Before compensation 1.5Uo VLF tanδ distribution by length at Group A-5. 49
Fig. 4-1-7. After compensation 1.5Uo VLF tanδ distribution by length at Group A-5. 49
Fig. 4-1-8. Before compensation 1.5Uo VLF tanδ distribution by three different lengths at each steps. 53
Fig. 4-1-9. After compensation 1.5Uo VLF tanδ distribution by three different lengths at each steps. 53
Fig. 4-1-10. Compensation factor by length at Group A-1 1.5Uo. 56
Fig. 4-2-1. Before compensation DTD distribution by three different lengths at step. 58
Fig. 4-2-2. After compensation DTD distribution by three different lengths at step. 58
Fig. 4-2-3. Before compensation 1.5Uo Skirt distribution by three different lengths at step. 60
Fig. 4-2-4. After compensation 1.5Uo Skirt distribution by three different lengths at step. 60
Fig. 4-3-1. Concept of R index. 71
Fig. 4-3-2. KEPCO replacement ratio in R index. 73
Fig. 4-3-3. History of management window. 75
Fig. 4-3-4. Distribution of R index in management window. 75
Fig. 4-3-5. Length of replacement cable and expansion cable. 81
Fig. 4-3-6. Over 30 years replacement ratio of CNCV cable and CNCV-W cable. 81