An On-Line WSN-based Monitoring System for Transmission Line Sag of Power Grid

近年來由於全球的輸電設備一旦遭逢意外事故包含天然環境災害、人為破壞等等都會對全國的供電造成很巨大的影響，因此，如何確保超高壓輸電線和電塔設備的安全問題為現今一個非常重要的議題。傳統的監測方式大多採用人力巡查的方式，此種方式較沒效率且無法即時的反應超高壓輸電線路與電塔之情況。 為了改善上述之情形，必須使用新的監測方式來確保超高壓輸電線即時的穩定性和安全性。本研究開發一自主式供電之無線感測系統應用於超高壓輸電線之安全監測上，同時結合遠距廣域傳輸技術，達到遠距離即時監測之目的。監測目標可分為輸電線路參數監測與電塔端安全參數監測兩大項目，輸電線路上的參數監測項目包含：輸電線導體溫度、環境溫濕度、環境照度、輸電線通過之電壓和電流、線路垂降程度及線路振動程度；而電塔則結合氣象模組用以監測當地氣候的變化，以溫溼度、風速、方向、雨量為主，同時為了預防電塔滑移或倒塌等事故，亦使用三軸加速度感測器監測電塔之振動與傾斜情形。 本研究另一主要目標為使用一角度-垂降之關係方程式來直接估算超高壓輸電線垂降程度並判斷輸電線之安全性，此方法之準確性藉由與不同長度與張力之輸電線實際測量資料比較可發現垂降誤差皆在10 cm以下。由於輸電線垂降程度與輸電線張力、輸電線熱容量、淨空高度有關，因此可藉由準確的垂降量測結果來評估輸電線機械狀態而不需要耗費額外的成本。此外，由於每個電塔建置的地形不盡相同，本研究提出一套垂降測距估算演算法(Sag-Clearance Estimated Algorithm)來計算每條輸電線實際上與地表障礙物最有可能發生接觸意外的位置。In recent years, the power transmission equipment around the world has suffered from severe accidents such as natural environmental disasters and vandalism, which cause a huge impact on the power supply of the whole country. Therefore, it is very important to ensure the safety of EHV (extra high voltage) transmission lines and electrical tower-related equipment. Traditional ways to monitor EHV transmission lines are to use human inspections, which are not efficient and cannot response to the events that occur on EHV transmission lines and electrical towers in real time. In order to improve the aforementioned problem, it is necessary to develop new monitoring technologies to ensure the stability and security of EHV transmission lines in real time. In this research an autonomous power wireless sensing system used to monitor EHV transmission lines is proposed. This system combines with the long-distance WAN transmission technology to achieve the purpose of remote real-time monitoring. The monitoring objectives can be divided into two parts: for the EHV transmission lines and for the towers. For transmission lines, the monitored parameters include the voltage and current of transmission lines, conductor temperature, ambient temperature and humidity, ambient illumination, vibration levels and sag. Each power tower is equipped with a meteorological module which measures temperature and humidity, wind speed and direction, and rainfall mainly to monitor local climate change. Additionally, in order to prevent electrical tower sliding or collapsing, a triaxial accelerometer is used to monitor the vibration tilt in the electrical tower. Another main objective of this study is to use an angle-sag relationship equation to directly estimate the sag of the EHV transmission lines. Different lengths and tension of transmission lines are tested to examine the accuracy of the proposed method. The research result shows that the sag errors are less than 10 cm. Because the degree of the sag of transmission lines is directly related to the tension of transmission lines, heat capacity, and head-room clearance, the sag can be evaluated without attaching extra costs. In addition, since the terrain where each electrical tower locates varies, this study proposes a sag-clearance estimated algorithm to calculate the relationship between each power line and ground obstructions to detect the critical location of the transmission line where the line is most likely to contact the obstacle.誌謝 i 摘要 iii Abstract iv 目錄 vi 圖目錄 viii 表目錄 x 第一章 前言 1 1.1 研究背景 1 1.2 研究動機及目的 3 1.3 論文架構 3 第二章 文獻探討 5 2.1 超高壓輸電網 6 2.1.1 超高壓輸電線之重要性和安全性 7 2.1.2 超高壓輸電線安全監測技術回顧 9 第三章 無線感測器網路架構 14 3.1無線感測器節點硬體設計 15 3.2無線感測器網路通訊協定種類 17 第四章 超高壓輸電網安全性監測系統 20 4.1超高壓輸電網監測系統架構 20 4.2系統組成單元介紹與運作流程 21 4.2.1元件介紹 21 4.2.2電力來源設計 31 4.2.3輸電線路監測系統 33 4.2.4閘道器端與其無線通訊設備 35 4.3垂降程度評估方法 39 第五章 實驗結果與討論 43 5.1 感測器校正 43 5.2 垂降程度分析 46 第六章 未來工作 50 參考文獻 5