- 學位論文
對地突波在低壓端過電壓之分析研究
Analysis of Overvoltage on Low-Voltage Side Caused by Ground Surge
摘要
突波可從輸電線路上或者接地路徑影響電力設備，其影響的程度和範圍依入侵路徑及能量大小而有不同，其中突波直接注入電力系統線路之傷害最大，瞬間巨大能量往往造成電力設備嚴重損害。雷擊為一大突波源，其中避雷針為主動引導能量釋放之裝置，由於雷電流會於接地電阻引起電壓升，將嚴重影響周邊之低壓用電設備。「隔離接地」為一直接有效之保護方式，本論文即研究電力系統接地和避雷針接地隔離與否之影響。此外雷突波電流峰值、雷擊突波電流波頭峻度及持續時間(波尾)對過電壓之影響亦為研究項目之一。 本論文分析雷突波經由接地路徑藉由傳導或感應，以直接或間接方式對低壓用電設備所造成的過電壓，論文以高壓設備進行實際量測，並同時用ATP程式進行模擬比較。主要研究項目為供電接地和避雷針接地之隔離與否及隔離距離效應，同時分析避雷針接地電阻大小之影響。論文最後提出隔離距離與過電壓數據，提供相關保護之參考。
並列摘要
Surge can influence the electric equipment through the transmission line of power or the earthed route. Its effecting level and range depend on both the invaded route and the energy size. The most serious damage will occur when the surge pours into the circuit of power system directly, since the serious harm of electric equipment can be caused by the enormous energy that circulates hither and thither in the circuit. Because the low-voltage facilities are the equipments that most close to the personnel, the endurance ability of surge striking influences the personal safety. So it is necessary to understand that striking energy of surge can be brought via various routes. The danger of low-voltage facilities caused by lightning surge will be increased string along the larger peak current of lightning surge, the higher high-degree of current wave-head of lightning surge, and the longer duration (wave tail) of lightning surge current. Therefore, we can not disdain the harm caused by the wave of lightning surge This thesis analyzes that the lightning surge can be conducted or inducted via the earthed route, and can cause the over voltage on low-voltage equipment from direct or indirect way. In the thesis, both ATP program simulation and actual measurement are used to prove that, the damage of low-voltage equipment can be reduced or avoided if the power supply earth is disconnected with the lightning rod earth. In addition, when the distance between power supply earth and lightning rod earth is far enough, or the earth resistance of lightning rod is small enough, not only the over voltage of low-voltage equipment caused by surge can be reduced but also the danger of personnel caused by inductive electricity can be decreased.