- 學位論文
雷擊保護與雷擊感應電壓估算之研究
Study on Lightning Protection and Lightning Induced-Voltages Estimation
摘要
由於台灣地處亞熱帶，在雷雨季節裡，尤其在夏季，特別容易發生雷電，當閃電擊中輸電線路時會注入巨大的能量，而雷突波會藉由輸電線傳播使得過電壓保護電驛動作造成電力傳輸中斷，對於供電品質影響甚大。 雷電分作好幾種，而對地面上的建築物及人類造成威脅的主要是以雲對地間雷，雲對地間雷又可分成上行雷與下行雷，其中以下行雷的發生頻率較高。目前的雷擊保護元件以傳統的法蘭克林避雷針和現代的消雷針為主，本研究的重點之一即在比較傳統之避雷針與現代之消雷針的構造、原理、保護效果以及國內外使用規範。 另一研究課題為，非直擊雷害造成鄰近區域內架空線上的感應電壓的探討，雷擊閃絡可視為長距離的放電暫態現象，過程中會使得雷擊周遭的電、磁場劇烈變動，將會在鄰近的金屬物件上感應出電壓造成二次的傷害。本論文對此的研究步驟是先將回復閃擊現象量化成數值表示後，利用Maxwell方程式推導出空間中電磁場強度，配合Agrawal Model描述電磁場與架空線的耦合現象，以傳輸線方程式求解感應電壓，最後將結果寫成MATLAB程式，運用電腦快速分析能力可解析不同雷擊條件下的架空線上的感應電壓值，提供設計電力系統保護協調時參考之用。
並列摘要
For a country situated at the subtropical zone, such as Taiwan, lightning occurs very often, especially in summer, when there are thunderstorms. When the lightning hit the overhead-lines, it would inject the huge energy into overhead-lines. Outage by surge through overhead-lines would decrease power quality. Lightning can be divided into many types. The one most threatening to people and structure is the cloud to ground discharged. There are two kinds of cloud to ground discharged. One is upward, and the other is downward. The downward lightening happens more frequently. At present, Lightning rods and Lightning Eliminators are the more popular devices of lightning protection. My research focus on compared Structure, theory, protection effect of those devices, and collected standards, experiments from foreign as well as domestic. Another research topic is evaluated lightning induced voltages on nearby overhead-lines. Lightning is a transient, high-current discharge whose path length is measured in kilometers. During flash, neighbor electromagnetic field change violently, that would induce voltages on close-by metal. To find induce-voltages on overhead-lines must be transformed lightning phenomenon into numeric equation first. Apply Maxwell-equations to equal space electromagnetic, using Agrawal Model to describe coupling between overhead-lines and electromagnetic. Transmission equation can find the solution of induce-voltages by lightning. Finally, this thesis applied above solutions will offer a program by MATLAB. It can find solutions quickly and correctly in different conditions.