高密度聚乙烯聚合礙子破損分析

HDPE Polymer Insulator Fracture Failure Analysis

台灣屬海島型氣候區，沿海電力設備瓷質絕緣礙子受海風、盬塵害及工業廢氣污染因子等嚴重影響，導致絕緣礙子表面閃絡，輸配電系統無預告的瞬間斷電，構成工商業重大損失，其中以半導體業、石化及鋼鐵工業危害最大。為了防止因礙子污損洩漏電流增加或產生閃絡等現象而造成電力系統損壞，分別使用不同材料及電壓等級之聚合礙子，以防止礙子表面水膜的生成，目前鹽塵害地區使用聚合礙子之趨勢日益增加，本文分別從11.4KV配電線路燒損跳脫的事故現場，收集事故及鄰近地區高密度聚乙烯聚合礙子。從電氣特性試驗、材質機械及化學性質，材質缺陷結構分析等分析結果進行探討絕緣老化破壞程度及電蝕性能測試。從外觀判斷事故樣品已高溫燒熔，其他樣品底部均有明顯電蝕現象，礙子表面污損物為現場環境之鹽塵害；事故樣品之傅立葉紅外線光譜（FTIR）及熱分析（TGA/DSC）分析結果，與新品比較明顯變質，而其他樣品表面之分析結果，與新品無明顯差異；從電氣模擬試驗之紫外光放電影像檢測，發現礙子底部螺栓部份明顯閃絡現象，判斷原因應是鹽塵害之堆積，造成局部電弧，致使材料遭電蝕及穿孔破壞，並產生高溫使樣品燒損，進而造成事故發生。

Taiwan islands locate in sub-tropic area. In this climate condition, the insulators on transmission and distribution lines along the seashore suffer from the impact of sea-wind, salt-fog and industrial pollutants respectively. Comparing to other climates, the severe weather parameters are significantly influence in insulator performance. Contamination flashovers have become the greatest concern to power lines during the past decades. A number of power failures are recorded on electric networks. To solve this problem, so far various efforts , gradually replacement of conventional insulators by polymer insulators for specific area have been made. In other words, polymer insulators serve as a countermeasure against contamination problems. This project is initiated in distribution lines aiming to investigate HDPE polymer insulators failure events and establish the fracture analysis techniques, in the consequence of improving power quality in distribution lines. The main results in this project are acquiring polymer insulators application information both in domestic and overseas, establishing analysis techniques both in materials (FTRI/TGA/DSC/SEM) and electricity (UV Corona Image Monitoring) and referring maintenance criteria on polymer insulators service. The failure occurred in the vicinity of the bottom of insulators with accumulated contaminants which caused tracking and erosion phenomena and induced high-temperature damage.