A Grid-Connection Power Supply Integrating Renewable Energy for Distribution Transformer Fault-Detection System

[[abstract]]本計畫「結合市電及再生能源供電之配電變壓器故障偵測系統」，旨在研製一密封型配電變壓器故障偵測及其電力供應系統。所提系統能有效地檢測出故障的變壓器，縮短電力搶修時間，迅速恢復供電。在檢測電路的電源供給上，由市電與太陽光電能同時供電，並可將多餘電力提供高亮度LED (Light Emitting Diode, LED)照明使用，或儲存於蓄電池中。因此，計畫中，提出嵌入返馳式之修正型SEPIC電力轉換器(Modified SEPIC Embedded Boost Converter, MSEBC)。在MSEBC系統中，融入柔性切換機制，藉以提升電能轉換效率。此外，全系統進行數位化，減少離散元件數量，縮減體積，提升系統可靠度。計畫全程期間原規畫為二年，將分年完成上述工作。第一年著重在配電系統的故障電流計算與分析，設計故障偵測電路，藉由故障接地電流來判讀變壓器的故障。第二年，完成 MSEFC系統，藉由主動功率開關元件的切換，控制市電、太陽光電能、蓄電池的電力流向，除供電給故障偵測電路與LED負載外，並兼具功因修正的功能。由於，計畫僅被核准一年，因此，將二年的工作規畫，結合並縮短為一年。藉由本計畫的執行，可以建立配電變壓器故障診斷的關鍵技術，整合電力系統、電力電子應用、與微處理控制等領域，提升應用技術層次，促進相關產品的開發。[[abstract]]The primary objective of this research is to design and implement a fault detection system for close-type distribution transformer and its power supply. The detection system can diagnose transformer fault effectively so as to find out a breakdown transformer and shorten the period of power failure. In the power supply system, a modified SEPIC embedded flyback converter (MSEFC) with soft-switching feature is proposed, which can process PV power, correct power factor, charge battery, drive light emitting diode (LED), supply power for the detection circuit and achieve high conversion efficiency.The controller of the overall system will be further implemented in a single chip to reduce the number of discrete components, lower the hardware volume, and improve reliability.The project will last for one year, and the aforementioned tasks will b finished,which includes：1) Fault current of distribution system is analyzed theoretically as well as a related fault detection system is designed, proposed, implemented, and tested. 2) The MSEBC and the novel MPPT are developed and demonstrated. By switching active switches, power flow is controlled and power factor correction is achieved. After accomplishing the tasks mentioned in the project, key techniques and technologies for transform fault detection can be established. Moreover, the application of the integrated field of power system, power electronics and micro-processor control is developed.[[note]]NSC99-2221-E327-04