地下電纜線路在檢測與維護上較架空線路難，發生故障還需花費大量的人力與成本來維修。預防故障成爲不斷强調的課題，其中地下電纜中最常發生事故的部分為電纜接頭，而局部放電漸漸成爲觀察電纜接頭之絕緣狀態的指標。針對電纜接頭之局部放電的監測設備越來越多，但礙於實際場域沒有電源，因此監測設備都會搭配電池以進行短期的量測。
地下電纜線路中的電纜接頭數量龐大，當監測設備需要經常更換電池，這無疑是巨大的人力與成本消耗。本文使用就地擷取能量的非接觸式電源，其使用開口式比流器以耦合方式感應電纜電流產生之磁場，將能量從一次側輸入至電源，電源中含有整流濾波器與具最大功率追蹤系統之直流-直流轉換器，在最大功率的形式下傳輸電能至超級電容中儲存。當超級電容充滿即放電，經穩壓器後再供應監測系統，待監測系統工作結束便重新充電，以此間歇供電的方式。因超級電容的極長循環壽命，讓監測系統能夠用上極長的時間。
本文針對超級電容能量特性分爲高電壓與低電壓兩種架構，進行充電與放電試驗，以超級電容之充電時間與最低可充電之電纜電流為試驗中兩大指標，分析與比較各架構之特性。最後提出不同電纜電流的背景下，可搭配三種擷取能量元件之比流器，讓使用者在裝設監測設備時能夠有更多的選擇組合。搭配最大功率追蹤的電源能應用於數安培至兩百安培的極廣電纜電流背景，其中間歇供電的等待時間能壓縮至半小時内，讓此電源在實際應用上是可行的。

The detection and maintenance in underground cable system are more difficult than the overhead cable system, and it costs much more money and manpower for repairing after fault. Prevention from faults is becoming a crucial topic, and the cable joint, the accessory of underground cable system, is the part where failure occurs the most. The main reason of failure is partial discharges, which has therefore become a standard to evaluate the state of insulation of the cable joint. A lot of measuring systems for partial discharge have been developed. However, the measuring system normally equips with a battery for a short-term measuring due to there are no installation of AC plug on the site.
A large number of cable joints in the underground cable system will cause a tremendous spending for regularly replacing the battery of measuring system. In this paper, a contactless power supply is developed for substituting the battery of measuring system. The power supply utilizes a split-core current transformer to convert the magnetic energy generated by cable current into electric energy in the secondary side. The energy in the secondary side will be stored in the supercapacitors in the form of maximum power after regulating by rectifier, filter and DC-to-DC converter with maximum power point tracking(MPPT). After fully charged, the supercapacitors will release and supply the measuring system through a voltage regulator. The supercapacitors will be charged again after the measuring is done, the repeated charging and releasing forms an intermittent supply for the measuring system.
In the experiments, the structures of power supply can be divided into high voltage and low voltage according to the energy characteristic. The both structures will be analyzed and compared based on the charging time and the lowest chargeable cable current in the experiments of charging and releasing. Beyond that, this paper also proposes using three elements of energy harvest for more collocations to be able to choose in a large range of cable current. Owing to MPPT, the waiting time of intermittent supply can be compressed into half an hour, making the proposed power supply to be applicable on site.

[1] A. Ghaderi, A. Mingotti, F. Lama, L. Peretto and R. Tinarelli, "Effects of Temperature on MV Cable Joints Tan Delta Measurements," in IEEE Transactions on Instrumentation and Measurement, vol. 68, no. 10, pp. 3892-3898, Oct. 2019.
[2] S. Das, R. Majumder and S. Singh, "Cable Joint Installation Time Optimization," in IEEE Transactions on Dielectrics and Electrical Insulation, vol. 24, no. 6, pp. 3959-3965, Dec. 2017.
[3] S. Kulkarni, S. Santoso and T. A. Short, "Incipient Fault Location Algorithm for Underground Cables," in IEEE Transactions on Smart Grid, vol. 5, no. 3, pp. 1165-1174, May 2014.
[4] X. Wang, C. C. Wang, K. Wu, D. M. Tu, S. Liu and J. K. Peng, "An Improved Optimal Design Scheme for High Voltage Cable Accessories," in IEEE Transactions on Dielectrics and Electrical Insulation, vol. 21, no. 1, pp. 5-15, February 2014.
[5] C. C. Yii, M. N. K. H. Rohani, M. Isa and S. I. S. Hassan, "Multi-end PD Location Algorithm Using Segmented Correlation and Trimmed Mean Data Filtering Techniques for MV Underground Cable," in IEEE Transactions on Dielectrics and Electrical Insulation, vol. 24, no. 1, pp. 92-98, Feb. 2017.
[6] O. Oñederra, F. J. Asensio, P. Eguia, E. Perea, A. Pujana and L. Martinez, "MV Cable Modeling for Application in the Digital Twin of a Windfarm," 2019 International Conference on Clean Electrical Power (ICCEP), 2019, pp. 617-622.
[7] L. Calcara et al., "Faults Evaluation of MV Underground Cable Joints," 2019 AEIT International Annual Conference (AEIT), 2019, pp. 1-6.
[8] 李卓翰，「地下電纜接頭局部放電之差動量測研究」，碩士論文，國立台灣科技大學，民國一零九年。
[9] 許冠華，「可攜式局部放電監測系統之研製」，碩士論文，國立台灣科技大學，民國一零八 年。
[10] 詹清貴，「地下電纜局部放電線上監控系統之非接觸式電源研製」，碩士論文，國立台灣科技大學，民國一零七年。
[11] 葉念祖，「具絕緣狀態評估機制的電力電纜接頭線上監測系統之研製」，碩士論文，國立台灣科技大學，民國一零六年。
[12] R. Ge, Z. Lin, N. Gong and J. Wang, "Design and Performance Analysis of Energy Harvesting Sensor Networks with Supercapacitor," 2017 IEEE 60th International Midwest Symposium on Circuits and Systems (MWSCAS), 2017, pp. 64-67.
[13] D. N. Nikolov, "A Comparative Study of Energy Storage Systems for Energy Harvesting Devices," 2020 XI National Conference with International Participation (ELECTRONICA), 2020, pp. 1-5.
[14] T. Hosseinimehr and A. Tabesh, "Magnetic Field Energy Harvesting from AC Lines for Powering Wireless Sensor Nodes in Smart Grids," in IEEE Transactions on Industrial Electronics, vol. 63, no. 8, pp. 4947-4954, Aug. 2016.
[15] C. M. Krishna, "Managing Battery and Supercapacitor Resources for Real-Time Sporadic Workloads," in IEEE Embedded Systems Letters, vol. 3, no. 1, pp. 32-36, March 2011.
[16] 張瑞村，「數位局部放電量測應用於高壓電纜終端接頭絕緣狀態之評估」，碩士論文，國立臺灣科技大學，民國九十四年。
[17] 張建國，「地下電纜接頭局部放電線上監控系統之研製」，碩士論文，國立臺灣科技大學，民國九十五年。
[18] P. Li, Y. Wen, Z. Zhang and S. Pan, "A High-Efficiency Management Circuit Using Multiwinding Upconversion Current Transformer for Power-Line Energy Harvesting," in IEEE Transactions on Industrial Electronics, vol. 62, no. 10, pp. 6327-6335, Oct. 2015.
[19] T. -C. Huang et al., "120% Harvesting Energy Improvement by Maximum Power Extracting Control for High Sustainability Magnetic Power Monitoring and Harvesting System," in IEEE Transactions on Power Electronics, vol. 30, no. 4, pp. 2262-2274, April 2015.
[20] Umans, Stephen D. (2014). Fitzgerald & Kingsley’s Electric Machinery (7th ed.) International Edition. Singapore: McGraw-Hill.
[21] 陳瓊興、陳竹正，「電子學實驗(上)(第六版) 」，全華圖書，民國一零四年。
[22] R. Chai and Y. Zhang, "A Practical Supercapacitor Model for Power Management in Wireless Sensor Nodes," in IEEE Transactions on Power Electronics, vol. 30, no. 12, pp. 6720-6730, Dec. 2015.
[23] W. Jiang, R. Hu and J. Zhang, "The PWM Phase-shifted Plus Feed-forward Control of The Boost Converter Applied in Supercapacitor Energy Storage System," 2011 International Conference on Electrical and Control Engineering, 2011, pp. 455-458.
[24] 江炫樟，「電力電子學」，全華圖書，民國九十二年。
[25] Nilsson, James W., & Riedel, Susan A. (2015). Electric Circuits (10th ed.) Global Edition. Kendallville, IN: Pearson.
[26] 馮垛生，「太陽能發電原理與應用」，五南圖書，民國九十八年。
[27] T. J. Silverman et al., "Reducing Operating Temperature in Photovoltaic Modules," in IEEE Journal of Photovoltaics, vol. 8, no. 2, pp. 532-540, March 2018, doi: 10.1109/JPHOTOV.2017.2779842.
[28] S. Stanzione, C. van Liempd, R. van Schaijk, Y. Naito, F. Yazicioglu and C. Van Hoof, "A High Voltage Self-Biased Integrated DC-DC Buck Converter With Fully Analog MPPT Algorithm for Electrostatic Energy Harvesters," in IEEE Journal of Solid-State Circuits, vol. 48, no. 12, pp. 3002-3010, Dec. 2013.
[29] G. Petrone, G. Spagnuolo and M. Vitelli, "An Analog Technique for Distributed MPPT PV Applications" in IEEE Transactions on Industrial Electronics, vol. 59, no. 12, pp. 4713-4722, Dec. 2012.